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Volume 92-B, Issue SUPP_I March 2010

Denis Williams Bartosz Wojewnik Pietro Tonino David Mikolyzk John Callaci Ryan Himes Anthony Wei Brian Magovern Dustin Volkmer Frederick H. Wezeman Guido Marra

Purpose: To determine if administration of recombinant bFGF in an alginate gel would increase early healing mechanical parameters in acutely injured rat rotator cuff tendon at specific time points.

Method: Sprague Dawley rats were randomly divided into 2 groups and had surgically created 1mm (half tendon width) full thickness injuries at exactly 2mm from insertion site of Infraspinatus on the humerus. 200ng of bFGF or vehicle control was administered to randomly chosen rats. Tendons were harvested at 1 week, 2 weeks and 4 weeks. In both groups, the Infraspinatus tendon was dissected, and left attached to the humerus. At the time of testing, the intact portion of the injured tendon was divided sharply across tendon fibers at the level of the injury leaving only the healing tissue callus in continuity with the remaining proximal and distal portions of the tendon and loaded to failure.

Results: At 1 week the injury group’s average load to failure was 0.60N versus 0.61N in the bFGF injury group P = 1.000. At 2 weeks the injury group’s average load to failure increased to 1.03N versus 2.08N in the bFGF injury group P = 0.440 At 4 weeks the injury group’s average load to failure increased to 3.93N versus 5.56N in the bFGF injury group P = 0.008 representing a 41% increase in ultimate load. At 4 weeks, callus size of the injury group was 0.4mm2 versus 2.7mm2 in the bFGF injury group P < 0.001. Stiffness at 4 weeks for the injury tendons was 2.15 N/mm versus 3.54 N/mm in the bFGF group P = 0.008.

Conclusion: At 4 weeks healing tissue of acutely injured rotator cuff exposed to bFGF has an increase in ultimate load to failure (41% compared to control), increase in tendon callus size and stiffness. Our findings suggest a role of bFGF or similar growth factors in accelerating the healing of injured rotator cuff tendon.

Claire H. Li Ru Li James P. Waddell Emil H. Schemitsch

Purpose: Vascular Endothelial Growth Factor (VEGF) is vital for both angiogenesis and osteogenesis. The aim of this study was to investigate the effect of cell based VEGF gene delivery on the proliferation and mineralization of rabbit osteoblasts in vitro.

Method: Primary cultured rabbit osteoblasts were divided into four groups (each n=6). In Group I, osteoblasts were transfected with pcDNA3.1-VEGF; in Group II, osteoblasts were transfected with pcDNA-Efficiency Green Fluorescent Protein (EGFP); in Group III, osteoblasts were treated with the supernatant of fibroblasts that were transfected with VEGF genes; and in Group IV, osteoblasts were treated with the supernatant of fibroblasts that were transfected with EGFP. The cells were cultured in a-EME with 10% FBS, 2% penicillin/streptomycin with or without 10-^7 M dexamethasone and 50μg/ml L-ascorbic acid for 28 days. In the last 4 days, the cells were stimulated to initiate calcium mineralized nodule formation by adding 10 mM B-glycerophosphate. They were stained by the Von Kossa technique so that the number and the area of the nodules could be assessed by an imaging analysis system.

Results: The cells transfected by VEGF were indicated by the EGFP marked cells under a fluorescent microscope. There was a significant difference in the total nodule area (mean 18.38 mm2 SE 3.73 and 5.07 mm2 SE 0.55, p< 0.05) and count (mean 18.67 SE 3.22 and 2.17 SE 0.40, p< 0.001) between Group I and Group II (ANOVA, SPSS). More unmineralized and smaller nodules were found in Group III and Group IV. However, the nodules in Group III covered greater areas with dark brown staining in the cell culture dishes when compared with Group IV.

Conclusion: The observations indicate that cell based VEGF gene delivery has a positive effect on the proliferation and mineralization of osteoblasts. The greatest effect is seen with direct transfection of osteoblast cells. Cell-based VEGF gene therapy may be used to promote fracture healing.

Karina Galoian Nandor Garamszegi Susanna P. Garamszegi Sean Scully

Purpose: Chondrosarcoma is the second most common malignancy in bone and results from unregulated growth of mesenchymal cells.. Chondrosarcoma does not appear to respond either to chemotherapy or radiation. Currently chondrosarcoma has no effective treatment and a new approach to adjuvant therapy for this tumor is urgently needed. We have previously reported that Matrix metalloproteinase -1 (MMP-1)gene expression is an independent predictor of survival in chondrosarcoma.(Scully, 2000). We have reported also that the expression of the large TNC splice variant may correlate with malignancy and poor clinical outcome in human chondrosarcoma and be implicated in the process of basement membrane invasion. The aim of the current study was to confirm that Tenascin-C large splice variant(TNC320) stimulates matrix metalloproteinase-1(MMP-1)expression and invasive potential and to elucidate molecular mechanisms underlying this activation.

Method: The chondrosarcoma cell line was recultured in alginate beads. (Guo et al, 1989)The beads contained exogenous proteins according to design. Alginate beads were dissociated later by chelation and the cells were pelleted by centrifugation. Gel electrophoresis and Western blotting were performed to demonstrate the expression of MMP-1 protein in the cells cultured with treatments. MMP-1 protein was detected by mouse antiMMP-1 monoclonal antibody from Chemicon. QPCR and RT-PCR were used to detect MMP-1mRNA expression with different treatments Transactivation of MMP-1 luc construct was detected in transiently transfected JJ012 human chondrosarcoma cultured cells. Reporter gene, Collagenase, Cell invasion assays and MMP-ELISA were performed for this study.

Results: The analysis of gene expression in cultured cells grown under different condition indicated significant increases of MMP-1mRNA steady-state levels in the cells with TNC 320 treatment. Gel electrophoresis demonstrated augmented MMP-1 protein in cells cultured with TNC 320. The result was confirmed by examining MMP-1 promoter transactivation of 30fold in comparison with control and other treatments. Both invasion and collagenase assays demonstrated 3 fold difference in the cells treated with TNC 320. Experiments with constitutively active expression kinases indicated that MMP-1 expression induced by TN320 was associated with MAPK cascade activation.

Conclusion: Preliminary results presented demonstrate that Tenascin-C 320kda splice variant stimulates MMP-1 expression and involves MAPK pathway. We hypothesize that Tenascin-C stimulates invasive potential of human chondrosarcoma cells via upregulation of MMP-1 expression.

Tamer Anwar Esmail Ahmed Michael Halpenny Harold Atkins Antonio Giulivi Geoffrey Dervin May Griffith Max Hincke

Purpose: Articular cartilage is a physiologically hypoxic tissue with a gradient of oxygen tension ranging from about 10% oxygen at the cartilage surface to less than 1% in the deepest layers. The overall goal of the study was to determine whether an injectable allogeneic/autologous fibrin scaffolds in combination with mesenchymal stem cells (MSCs) is suitable for articular cartilage tissue engineering, and to determine the effect of hypoxic culture conditions on the stability of cell-fibrin scaffolds. The secondary goal was to enhance the accumulation of extracellular matrix (ECM) inside the fibrin scaffold under these conditions.

Method: Chondroprogenitor clonal cell line RCJ3.1C5.18 (C5.18) and human mesenchymal stem cells (hMSCs) were encapsulated in fibrin hydrogel and fibrin glue scaffolds. The stabilization of fibrin scaffolds and development of ECM components were evaluated using zymography, SDS-polyacrylamide electrophoresis (SDS-PAGE), immunochemistry, spectrophotometry, RT-PCR including real time and histology (Ahmed TA., et al. Tissue Engineering2007;13(7): 1469–77).

Results: After encapsulation of C5.18 and hMSCs, fibrin gels quickly degraded under normoxic conditions (21 % oxygen) due to upregulation of plasminogen and matrix metalloproteinases (MMPs) genes especially MMP-2, -3, and -9. Protease inhibitors such as aprotinin and galardin (GM6001), in combination or separately, prevented the fibrin-C5.18 hydrogels breakdown for up to 5 weeks. Only a combination of aprotinin and galardin resulted in accumulation of ECM components such as collagen II and aggrecan. In contrast, fibrin-hMSCs hydrogels were found to be stable under hypoxic conditions (5% O2) for up to 4 weeks in the absence of inhibitors, suggesting that hypoxic conditions may downregulate the expression of the enzymes responsible for fibrin-hydrogel breakdown.

Conclusion: These results suggest that in C5.18 and MSCs cell lines, expression of matrix metalloproteinases (MMPs) and plasmin is upregulated under normoxic conditions and is responsible for fibrin-hydrogel breakdown. Moreover, inhibition of both proteases is required to enhance the accumulation of ECM. However, fibrin hydrogel scaffolds were stabilized under low oxygen tension, which is more physiological than normoxia and therefore these constructs may be stable after implantation in the absence of protease inhibitors.

Steven Gitelis Thomas Turner Robert Urban

Purpose: To test a CaSO4/CaPO4-TCP composite bone graft substitute in a crtically sized bone defect.

Method: Twenty dogs had a contained medullary defect created in the proximal humerus. In ten dogs, the defect was treated with CaSO4/CaPO4-TCP composite graft (PRO-DENSE, Wright Medical) and studied for 13 weeks (N=5) and 26 weeks (N=5). In the other ten dogs, the defect was treated with autograft and followed for 13 weeks. An additional ten unoperated humeri were used to establish the properties of normal canine bone. The area fraction, ultimate compressive stress and modulus of elasticity of bone in the experimental and normal humeri were quantified using histomorphometric and mechanical methods and analyzed using the Mann-Whitney test.

Results: At 13 weeks, the area fraction, compressive stress and modulus of elasticity of new bone in the defects was several-fold greater (p ≤ 0.005) using CaSO4/CaPO4-TCP composite graft compared to defects treated with autograft. The area fraction and compressive stress of new bone using CaSO4/CaPO4-TCP composite graft were also several fold greater (p≤.009) compared to normal bone, but there was no difference in the modulus of elasticity. Although the compressive stress was still greater (p=0.047) at 26 weeks for defects treated with the composite graft compared to normal bone, the regenerated bone had remodeled to a normal cancellous architecture, incorporating minute fragments of residual graft.

Conclusion: CaSO4/CaPO4-TCP composite graft produced a several-fold greater amount and strength of bone than autogenous graft bone at 13 weeks. There was no modulus mismatch between the regenerated and native cancellous bone. The composite graft holds promise for non-load bearing applications where dense, strong bone formation at earlier time points would be advantageous, potentially resulting in quicker return to activity.

Rad Zdero Michael Olsen Salah Elfatori Tom Skrinskas Emil H. Schemitsch Cari Whyne Herbert P. Von Schroeder

Purpose: The mechanical behavior of human scapholunate ligaments is not described well in the literature regarding torsion. Presently, intact scapholunate specimens were mechanically tested in torsion to determine if any tensile forces were generated as a result.

Method: Scapholunate specimens (n=19) were harvested and inspected visually. Scaphoid and lunate bones were potted in square chambers using epoxy cement. The interposing ligaments remained exposed. Specimens were mounted in a specially designed test jig and remained at a fixed axial length during testing. Using angular displacement control, ligaments were subjected to a torsional motion regime that included cyclic preconditioning (25 cycles, 1 Hz, triangular wave, 5 deg max), ramp-up to 15 deg at 180 deg/min, stress relaxation for 120 sec duration, ramp-down to 0 angulation at 180 deg/min, rest period for 5–10 minutes, and torsion-to-failure at 180 deg/min. Torque and axial tension were monitored simultaneously.

Results: Tests showed a coupled linear relationship between applied torsion and the resultant tensile forces generated for the ligament during ramp-up (Torsion/Tension Ratio = 38.86 +/− 29.00 mm, Linearity Coefficient R-squared = 0.89 +/− 0.15, n=19), stress relaxation (Ratio = 23.43 +/− 15.84 mm, R-squared = 0.90 +/− 0.09, n=16), and failure tests (Ratio = 38.81 +/− 26.39 mm, R-squared = 0.77 +/− 0.20, n=16). No statistically significant differences were detected between the Torsion/Tension ratios (p=0.13) or between the linearity (R-squared) of the best-fit lines (p> 0.085).

Conclusion: A strong linear relationship between applied torsion and resulting tensile forces for the ligament was exhibited during all testing phases. This may suggest that there is interplay between torsion and tension in both the stabilization of the scapholunate ligament during normal physiological motion and during resistance to injury processes. This is the first report in the literature of the coupling of torsion with tension for the scapholunate ligament.

Richard Freiberg Charles J. Glueck

Purpose: We hypothesized that thrombophilia-hypofibrinolysis are risk factors for femoral head osteonecrosis. Separately, we hypothesized that when Enoxaparin is started at Ficat stages I or II in patients with idiopathic osteonecrosis and thrombophilia-hypofibrinolysis, progression of osteonecrosis can be stopped.

Method: We compared measures of thrombophilia and hypofibrinolysis in 71 adults with idiopathic osteonecrosis, in 62 with corticosteroid-associated secondary osteonecrosis, and in gender-race matched healthy controls. In a prospective Enoxaparin treatment study, 16 patients (25 hips)with one or more thrombophilic-hypofibrinolytic disorders and Ficat Stages I–II idiopathic ON of the hip(s). Enoxaparin (60 mg/day) was given for the first 12 weeks of the study. Yearly X-rays were taken for 5–7 years follow-up (average 6 years). Maintenance of Ficat Stages I-II versus progression to Stages III–IV or total hip replacement was the study outcome.

Results: Patients with idiopathic osteonecrosis were more likely than controls to have high (> 150%) levels of heritable thrombophilic Factor VIII (19/71 [27%] vs 3/66 [5%], p =.0004), and to have inherited high levels of hypofibrinolytic lipoprotein(a) (25/69 [36%] vs 12/67 [18%], p =.016). Patients with secondary osteonecrosis were more likely than controls to have high (> 150%) levels of Factor VIII (16/62 [26%] vs 5/60 [8%], p =.011), to be heterozygous for the Factor V Leiden mutation (6/61 [10%] vs 0/61 [0%], p =.028), and to have heritable thrombophilic resistance to activated protein C (8/51[16%] vs 2/59[3%], p =.042). After 3 months on Enoxaparin, based on intent to treat, 17 of 25 hips (68%) have remained Ficat Stages I–II at 6-year follow-up versus approximately 20% 2-year hip survival in untreated historical controls. This suggests that the original 12 week Enoxaparin thromboprophylaxis produced lasting benefit.

Conclusion: Inherited thrombophilia-hypofibrinolysis are risk factors for both idiopathic and secondary osteonecrosis of the head of the femur. The importance of the diagnosis of thrombophilia-hypofibrinolysis lies in the potential to stop the progression of osteonecrosis when Enoxaparin is started at Ficat stages I–II. Enoxaparin seemingly prevents progression of idiopathic hip ON, causing a decrease in the incidence of total hip replacement at 6 years follow-up.

Emma V. Dare Philippe Poitras Geoffrey Dervin Antonio Giulivi May Griffith Maxwell T. Hincke

Purpose: The objective of this project is to evaluate the human fibrin glue, CryoSeal®, as a scaffold for articular cartilage tissue engineering. An autologous system would eliminate risks associated with biocompatibility and virus transmission.

Method: Human articular chondrocytes were isolated from articular cartilage harvested from consenting patients undergoing total knee arthroplasty. The cells were encapsulated into CryoSeal® fibrin glue – which is derived from a single patient’s plasma using the Cryo-Seal® Fibrin Sealant System (Thermogenesis Corp.) – and cross-linked with genipin, which is a natural cross-linking agent with anti-inflammatory activity. The resulting gels were cultured in vitro for up to 7 weeks under either normal (21%) or low oxygen (5%) conditions and were evaluated for mechanical properties, extracellular matrix (ECM) production, viability, and biodegradation. Fibrin glue components were isolated from either fresh or frozen plasma.

Results: The dynamic compression modulus of the genipin cross-linked fresh plasma (FSP) CryoSeal® gels increased by ~4.4-fold over 5 weeks in culture. The glycosaminoglycan (GAG) content of the FSP gels increased by 4.7-fold over 5 weeks in low oxygen (LO) culture, which was 1.7-fold greater than in normal oxygen (NO) culture. The total collagen content of the FSP cultures increased by 6.0-fold over 5 weeks in LO culture, which was 2.2-fold greater than in NO culture. These changes in ECM were confirmed by histology (Alcian Blue) and immunostaining (to detect collagen II, collagen I, aggrecan, Sox9) of gel cryosections. After 5 weeks in LO culture the FSP CryoSeal®-encapsulated chondrocytes expressed a 6.4 ± 1.1 fold increase in collagen II gene expression, which was 5.8 ± 1.0 fold greater than in NO cultures. In addition, chondrocyte viability within the FSP and frozen plasma (FZP) CryoSeal® gels was ~90% at both 24 hours and 2 weeks after gelation. When fibrin hydrogels were implanted subcutaneously into rats it was found that inflammation was inhibited with increasing genipin and when the material origin was species-specific.

Conclusion: The CryoSeal® fibrin gel system demonstrates promise for autologous human articular cartilage tissue engineering. An in vivo orthopaedic implantation model must be developed for further testing.

Kevin Hildebrand Mei Zhang David Hart

Purpose: To determine if cells isolated from the rabbit joint capsule in post-traumatic joint contractures have altered responses to stimuli and inhibitors.

Method: The right knee of three rabbits had cortical windows removed from the femoral condyles followed by 4 weeks of immobilization, a recently developed model of post-traumatic contractures. The contralateral knee served as an unoperated control. Primary cells (2.5 × 105 cells/ml) isolated from the posterior capsule were mixed with neutralized bovine collagen solution and then cast into tissue culture plate wells. Gelation occurred overnight and then the cells were treated with 1% serum replacement (control), 10 ng/mL TGF-beta1, and the TGF-beta1 receptor kinase inhibitor SB431542 at 10 microM or 0.1 microM. Gel contraction was measured at 24 post release from the edges of the well using captured images of the gels and computer software.

Results: In all groups the contracture (injured) knees displayed significantly greater collagen gel contraction than control capsule cells. The addition of the TGF-beta1 increased, while SB431542 at the higher dose decreased, the extent of contraction by contracture and control cells. The TGF-beta1 contraction effect was neutralized by the addition of the inhibitor at the higher dose. In terms of sensitivity to the manipulations, the contracture capsule cells had greater responses to the stimulant and inhibitor.

Conclusion: This work is significant as this is the first description of joint capsule cell properties. In post-traumatic contractures, these cells have an intrinsically increased contraction ability at baseline conditions (serum replacement), and these cells also have heightened responses to TGF-beta1 and the TGF-beta1 receptor kinase inhibitor SB431542, a known pathway associated with fibrosis. These results support future work modifying this pathway directly, or by manipulating cells that liberate TGF-beta1. One such strategy would be to prevent mast cells from degranulating as they are a source of TGF-beta1 and other profibrotic growth factors, cytokines and enzymes.

Derek J. Rutherford Cheryl L. Hubley-Kozey William D. Stanish

Purpose: To test the null hypotheses that no significant differences in the net external knee adduction moment waveform captured during gait exist between neutral, toe in and toe out foot progression angle (FPA) modifications and between those with mild to moderate knee OA and asymptomatic control subjects.

Method: Ten patients with mild to moderate knee OA (age 45±7 years) and 16 asymptomatic control subjects (age 54±8 years) participated. Informed consent was obtained for all participants. Three-dimensional (3D) motion and ground reaction force data were recorded during gait. Five trials of each condition,

Self-selected walking (Neutral),

Toe out walking (10o> self-selected, velocity +/− 0.1 m/s of self-selected) and

Toe in walking (10o

Results: There was a significant condition effect for FPA (Neutral=7o, Toe out=24o and Toe in=−9o) and a significant group effect for walking velocity (Asymptomatic=1.46m/s, Knee OA=1.27m/s). In both groups, a toe out FPA produced

a reduction in the overall knee adduction moment (captured by PC1),

a reduction in the late stance magnitude of the knee adduction moment magnitude (captured by PC2 and PC3) and

an increase in the early stance knee adduction moment magnitude (captured by PC2) (p< 0.05).

Conclusion: The knee adduction moment is considered an indicator of medial tibio-femoral compressive loading. In this study, a toe out FPA modification during gait altered the characteristics of the knee adduction moment. A reduction in the overall magnitude, more specifically during late stance was found with the toe out gait modification. An increased initial stance peak magnitude was also found during toe out gait. This finding is novel, indicating that a greater peak medial compartment load is produced

Billy K. Parsley D. Gordon Allan Brad Dyrstad Joseph C. Milbrandt

Purpose: Metal-on-metal (MOM) bearing surfaces release ions locally and into the systemic circulation. This elevation raises concern about the long term effects of elevated metal ions. The goal of the present study was to monitor serum cobalt (Co) and chromium (Cr) levels in patients after MOM resurfacing hip arthroplasty with the Cormet 2000 prosthesis. We present here pilot data on Co and Cr levels in patients with bilateral versus unilateral hip resurfacing devices.

Method: We prospectively collected patient characteristics, outcome, and serum samples from device implanted subjects at 6 months, 1, 2, and 3 years following surgery. Unilateral patients had one implant during the entire course of follow-up and bilateral patients were included after the second implant surgery was performed. Serum Co/Cr levels were determined using high-resolution inductively coupled plasma mass spectrometry. Students t-test was used to compare ion levels in two groups based on the number of resurfacing implants (bilateral versus unilateral).

Results: 41 unilateral and 9 bilateral subjects were enrolled and followed for serum Co and Cr levels. In general, Co/Cr levels were increased at all time points when compared to control levels in both groups. Bilateral subjects had average serum levels concentrations significantly higher than those observed for unilateral cases (Co: 5.99 vs 2.56 μg/L (p=0.0001); Cr: 6.66 vs 3.60 (p=0.0009).

Conclusion: Elevated serum Co/Cr levels were observed at all time points following implantation in both groups and serum levels were nearly 2 times higher in the bilateral group. Based on these preliminary findings, patients undergoing bilateral total hip resurfacing arthroplasty may need to be monitored more closely than those patients receiving unilateral devices. In addition, these bilateral cases may be at a greater risk of ion level toxicities than the unilateral population.

Kevin Debiparshad John Antoniou Olga L. Huk Fackson Mwale David J. Zukor Alain Petit

Purpose: Metal-on-metal articulations in total hip arthroplasty (THA) have been recently re-introduced for the treatment of osteoarthritis. There have been excellent short-term clinical outcomes reported. The long-term clinical results of these implants are still unknown. In this study, we examined the four to ten -year results of metal-on-metal total hip arthroplasty at our institution.

Method: All patients receiving a metal-on-metal prosthesis were prospectively registered in a computerized database. The period July 1997 – May 2003 was selected for analysis. This group contained 251 cases (207 patients) and had an average follow-up of 6.8 years. Of the 251 implants the femoral head components were either Metasul (203) or Ultamet (48) and the acetubular component Fitek (12), Interop (191) or Pinnacle (48). All patients were assessed with the Harris hip and UCLA activity scores at routinely scheduled follow-up visits. The mean age of patients at surgery was 52 years (18 to 70 years old). The average follow-up was of 6.8 years (4.2–10 years). No patients were lost to follow-up.

Results: The mean UCLA and Harris hip score pre-operatively were 3.6 (1–8) and 42 (15–81), respectively. Values of the UCLA and the Harris hip scores on the most recent follow-up visit were 7.0 (60% of patients had a score equal to or greater than 7) and 85 (70% of patients had a score equal to or greater than 85), respectively. Thirteen hips (5.1%) were revised in total: 1 (0.4%) for early deep infection, 1 (0.4%) for revision of undersized stem and 11 (4.3%) for acetabular revisions due to manufacturing defects. Radiological results showed no osteolysis and 9 non-progressive radiolucency.

Conclusion: At four to ten year follow-up, metal-on-metal total hip replacement provides consistently good clinical and radiographic results with a low revision rate. They provide longstanding pain alleviation and improved function and activity levels in patients suffering from osteoarthritis.

Pascal-A. Vendittoli Martin Lavigne Alain G. Roy Daniel Lusignan

Purpose: Surface replacement arthroplasty is being increasingly offered as the treatment of choice to young and active patients with hip arthritis with proposed advantages including bone conservation and better functional outcome. Excellent outcome has been reported in the few recent short-term clinical series of surface replacement arthroplasty. However they have an inbuilt patient selection bias. There are no direct prospective randomized studies comparing the newer generation of surface replacement arthroplasty with conventional total hip arthroplasty. Our study addresses this issue.

Method: 210 hips in 194 patients were randomized to receive either an uncemented total hip arthroplasty or a hybrid metal-on-metal surface replacement arthroplasty. Complications, functional outcomes, along with patient satisfaction and radiographic evaluation were compared at a minimum of two years follow up.

Results: Patients in both groups demonstrated a very high satisfaction rate and achieved similar functional scores. Four dislocations occurred in the THA group (one needing acetabular cup revision) and none in the SRA group. There were no femoral neck fractures in the surface replacement arthroplasty group. However, two surface replacement arthroplasty cases underwent revision for late head collapse and one needed a femoral neck osteoplasty for persisting femoro-acetabular impingement. Better biomechanical restoration was attained with surface replacement arthroplasty. All the components were considered to be stable after an average follow up of 45 months.

Conclusion: Although surface replacement arthroplasty of the hip offer similar patient satisfaction, functional outcome and complication rate as an uncemented total hip arthroplasty in a young and active group of patients, different complications were associated to each procedure. Better patient selection could avoid some of the complications in the surface replacement arthroplasty group. One main advantage that remains for the surface arthroplasty technique it is the proximal femoral bone stock preservation. However, long term survival analysis is necessary to determine the true advantage of these implants over total hip arthroplasty.

Giles Nicholas Heilpern Nirav Shah Michael J. F. Fordyce

Purpose: We report a series of 117 consecutive metal-on-metal Birmingham Hip Resurfacings in 105 patients with a minimum of 5 year follow up.

Method: Patients were followed up both clinically and radiographically for a minimum of 5 years following implantation. Revision of either the femoral or acetabular component during the study period is defined as failure.

Results: We followed up 114 of 117 hips (97%). We had 4 failures giving us survivorship at 5 years of 97% (95% confidence interval (CI) 94–100). The mean follow up was 72 months and the mean age at implantation 54.5 years old. The mean Oxford Hip Score fell from 41.6 preoperatively to 15.3 postoperatively (p< 0.0001). The mean Harris Hip Score at 5 year follow up was 96.4. The UCLA Activity Scale rose from 3.93 preoperatively to 7.54 postoperatively (p< 0.001). Radiographic analysis revealed neck thinning in 12 patients (10%) and we define a method of measuring this. The average stem shaft angle in our cohort was 130 degrees and the average cup angle was 36 degrees. Heterotropic ossification was present in 17 hips (15%).

Conclusion: This study confirms that metal-on-metal resurfacing produces an excellent clinical and functional outcome in the younger patient who requires surgical intervention for hip disease. The results compare favourably with those from the originating centre and confirm that resurfacing is well suited for younger higher demand patients. It is the first study with a minimum 5 year follow up outside the originating centre.

Dick van der Jagt Anton Schepers Kingsley Nwokeyi Lipalo Mokete

Purpose: Whole blood metal ion levels remain a concern in those patients undergoing total hip replacement with metal bearing surfaces. The determination of baseline reference levels are essential if useful information can be gleaned from in vivo studies of functioning implants. We set out to prospectively determine chromium and cobalt metal ion concentrations in patients undergoing total hip replacement to determine reference levels of these metal ions.

Method: 100 patients with normal renal function, no occupational or environmental exposure to cobalt and chromium, and an absence of implanted metals were recruited into the study. Metal ion levels were determined using two different assay methods. Both ICP-MS (Inductively Coupled Plasma Mass Spectroscopy) and GFAAS (Graphite Furnace Atomic Adsorption Spectroscopy) are well recognized analytical techniques for the quantification of trace elements. Levels were correlated with gender, age and place of residence.

Results: There was considerable variability in whole blood metal ion levels, with the ICP-MS being more sensitive and consistent than the GFAAS method. Direct comparison of concentration levels determined by the two methods revealed no significant correlation. There was no correlation with age, gender and place of residence.

Conclusion: Our findings would favour the use of the ICP-MS to determine reference levels and as a baseline for metal ion surveillance pre-operatively in patients undergoing metal-on-metal total hip replacements. We also determined that changes in whole blood metal ion levels are more significant than actual levels in patients who have undergone total hip replacement.

Nelson V. Greidanus Alexander Siegmeth Wael Rahman Donald Garbuz Bas A. Masri Clive P. Duncan

Purpose: The purpose of this study was to prospectively evaluate a consecutive series of patients receiving metal on metal hip resurfacing arthroplasty with regards to outcomes and complications at minimum of 2 years follow-up.

Method: A prospective evaluation of all patients receiving hip resurfacing was performed including baseline evaluation (demographics, WOMAC, SF12, Oxford Hip Score) and minimum 2 year follow-up assessment (WOMAC, SF12, Oxford Hip Score, UCLA activity score, Patient Satisfaction, Complications). No patients were lost to follow-up.

Results: 143 hips in 127 patients received metal-on-metal hip resurfacing arthroplasty. The mean age was 52 years and the primary diagnosis was osteoarthritis or avascular necrosis, Significant improvements were noticed across all baseline quality of life instruments (p< .05) with final mean WOMAC and Oxford Scores 95 (normalized 0–100). Final post-op satisfaction was mean 95 out of 100. Two patient sustained post-operative femoral neck fractures and required revision. An additional two patients required revision for ongoing hip pain. One patient sustained a sciatic nerve palsty and one additional patient required acetabular component repositioning on the same day as the index procedure. Revision procedures involved conversion of resurfacing femoral component to cementless total hip stem with large diameter metal head and preservation of acetabular component. Acetabular component survivorship is 99% and femoral component survivorship is 97% at 2 year follow-up.

Conclusion: Our short to midterm data, from an independant center, suggests excellent improvement in quality of life with high levels of patient satisfaction and postop acitivity level. Our comprehensive post-operative quality of life assessment demonstrates restoration of the hip to rival that of the normal non-arthritic hip joint. Complications unique to resurfacing arthroplasty occur and were not predictable based on pre-operative or intra-operative patient-specific features.

Mohit Bhandari

Purpose: Surgeons agree on the benefits of intramedullary nailing of tibial shaft fractures. The SPRINT primary objective aimed to assess the impact of reamed versus unreamed intramedullary nailing on rates of re-operation in patients with tibial shaft fractures.

Method: The Study to Prospectively Evaluate Reamed Intramedullary Nails in Tibial Fractures (SPRINT) was a multi-centre, randomized trial including 29 clinical sites. SPRINT enrolled 1319 patients with open or closed tibial shaft fractures. Patients, outcome assessors, and data analysts were blinded to treatment allocation. Peri-operative care was standardized, and re-operations before 6 months were not permitted unless there was critical bone loss. Patients received a statically locked intramedullary nail with either reamed or unreamed insertion. The primary outcome was re-operation to promote healing, treat infection, or preserve the limb. We planned a priori to conduct a subgroup analysis of outcomes in patients with open and closed fractures. Our sample size calculations required 1200 patients followed for 1 year.

Results: Of 1319 enrolled patients, 1226 patients were followed to 1 year. Across treatment groups, patients did not differ in age, gender and closed and open fracture types (I-IIIB). The overall event rate was 17.8% (13.7% closed, 26.5%, open fractures). A significant subgroup interaction effect in patients with open versus closed fractures (p=0.01) mandated a separate analysis for each subgroup. In 826 patients with closed fractures, patients with a reamed nail had a relative risk reduction of 33% (95%CI: 4–53%, P=0.03). This treatment effect was largely driven by differential autodynamization rates (rel. risk: 0.42, p=0.01). Among 400 patients with open fractures, there was a trend towards an increased risk of an event (rel. risk=1.27, p=0.16) for those who received a reamed nail.

Conclusion: Our overall incidence of revision surgery was lower than reported in previous studies. Possible reasons for the overall lower event rates in SPRINT are:

standardization of surgical and post-surgical care resulted in superior care among the SPRINT centres and surgeons and

proscription of surgery until after 6 months. Optimizing peri-operative care and avoiding premature re-operation may substantially decrease the need for re-operation in tibial fracture patients.

Pascal-A. Vendittoli Martin Lavigne Muthu Ganapathi Klaus-Peter Gunther

Purpose: The aim of our study was to compare the precision and effectiveness of a CT-free computer navigation system against conventional technique (using a standard mechanical jig) in a cohort of unselected consecutive series of hip resurfacings.

Method: 139 consecutive Durom hip resurfacing procedures (51 navigated and 88 non-navigated) performed in 125 patients were analysed. All the procedures were done through a posterior approach by two surgeons and the study cohort include the hip resurfacings done during the transition phase of the surgeons’ adoption of navigation.

Results: There were no significant differences in the patients caracteristics, native neck-shaft angles, component sizes and blood loss between the two groups. There was a significant difference in the operative time between the two groups (111 minutes for the navigated group versus 105 minutes for the non-navigated group; p=0.048). There were 4 cases of notching in the non-navigated group. There was no other intra-operative technical problem in either of the groups nor were there any femoral neck fractures. No significant difference was found between the mean post-operative stem-shaft angles (138.5° for the navigated group versus 139.0° for the non navigated group, p=0.740). However there was a significant difference in the difference between the planned stem-shaft angle versus the post-operative stem-shaft angle (0.4° for the navigated group versus 2.1° for the non-navigated group; p=0.005). While, none of the cases in the navigated group had a post-operative stem-shaft angle with more than 5° deviation from the planned neck-shaft angle when compared to 33 cases (38%) in the non-navigated group (p≤0.001). For a given patient with a target angle set, it is estimated that positioning precision using the navigation is 1.3° +/− 0.9°, compared to 4.4° +/− 3.6° without navigation (p< 0.0001).

Conclusion: Hip resurfacing is a technically demanding procedure with a steep learning curve. Varus placement of the femoral component and notching have been recognised as important factors associated with early failures following hip resurfacing. While conventional instruments allowed reasonable alignment of the femoral component, our study has shown that use of computer navigation allows more accurate placement of the femoral component even when the surgeons had a significant experience with conventional technique.

Michael J. Dunbar Richard Kjar Allan Hennigar

Purpose: Resurfacing arthroplasty (RA) is becoming popular as an alternative to total hip arthroplasty (THA). Direct to consumer advertising reports good to excellent outcomes and patients sometimes seek RA on the assumption that it provides increased survivorship over THA. We report the 5 year survivorship of 25 RA procedures done at one institution.

Method: 25 patients were prospectively followed after receiving a Conserve Plus RA through a direct lateral approach between 2002 and 2005. There were 22 males and 3 females with an mean age at surgery of 42 years. The average length of follow-up was 40 months. Failure was defined as revision of the components or a pending revision.

Results: At a mean of 2 years follow-up, 3 patients had been revised and 2 more were scheduled for revision surgery for a failure rate of 20%. Reasons for revision included 1 neck fracture and 2 aseptically loose acetabular components. The 2 patients waiting for revision also had aseptically loose acetabular components. Patients receiving or requiring revision were operated on throughout the series and were not necessarily part of the surgical learning curve.

Conclusion: RA of the hip done through a direct lateral approach in this series had an unacceptably high failure rate for aseptic loosening of the acetabular component.

Brad Petrisor Mohit Bhandari Emil H. Schemitsch Sheila Sprague David Sanders Kyle Jeray Beate Hanson

Purpose: The choice of irrigating fluid and delivery pressure remains controversial. Identifying surgeons’ preferences in techniques and the rationale for their choices may aid in focusing educational activities to the orthopaedic community as well as planning future clinical trials. Our objective was to clarify current opinion with regard to the irrigation of open fracture wounds.

Method: We mailed and delivered a cross-sectional survey using a sample-to-redundancy strategy to members of the Canadian Orthopaedic Association and attendees of an international fracture course (AO, Davos, Switzerland) to examine surgeons’ preferences in the initial management of open fracture wounds.

Results: Of the 1,764 surgeons who received the questionnaire, 984 (55.8%) responded. In the management of open wounds, most surgeons surveyed, 676 (70.5%), favoured normal saline alone, however 16.8% used Bacitracin. Many surgeons, 695 (71%) used low pressures when delivering the irrigating solution to the wound, however variation exists in what constituted high versus low pressure lavage. Surgeons supported the need for a clinical trial evaluating outcomes following both the use of different irrigating solutions as well as irrigating pressures [803 (84.8%) and 730 (77.6%) respectively].

Conclusion: The majority of surgeons favour both normal saline and low pressure lavage for the initial management of open fracture wounds.

Kelly Ann Lefaivre Darin Davidson Henry M. Broekhuyse

Purpose: We aimed to determine the effect of delay to surgery in hip fracture patients, including in hospital mortality, major complications, minor complications and length of hospital stay.

Method: We identified 615 eligible patients from the VGH Orthopaedic Trauma database between 1998 and 2002. A thorough chart review was performed. Age, gender, time from admission to surgery, pre-existing medical comorbidity, length of acute care hospital stay, major medical complications, minor medical complications and in hospital death were recorded and categorized. Patients were categorized into three risk groups for pre-existing comorbidity, and three groups for delay to surgery (48 hours). Chi-squared tests were performed to determine the association of delay to surgery to death, major complications, minor complications and length of stay, as a categorical variable. Multivariate logistic regression analysis was used to evaluate these associations, while adjusting for age, gender, and pre-existing medical comorbidity. Anvoa test was used to evaluate the association between length of stay, as a continuous variable, and delay to surgery.

Results There were 471 female patients, and 141 male patients. We identified 52 deaths (8.5%), 72 major complications (11.7%) and 238 minor complications (38.7%). The delay to surgery was < 24 hours in 346 patients (56.3%), 24–48 hours in 216 (35.1%), and > 48 hours in 50 (8.1%). The mean length of hospital stay was 23.4 days. Chi squared test showed no statistically significant association between delay to surgery and in hospital death (p= 0.787), despite a trend to increasing death (< 24 hours 8.1%, 24–48 hours 8.3%, > 48 hours 12.2%). There was no statistically significant association between delay and minor complications. Statistically significant associations between delay to OR and length of hospital stay (p= 0.0026), and the occurrence of a major complication (p=0.0085) were found. Regression analysis of major complications revealed an odds ratio of 1.47 for the > 48 hour group compared to the < 24 hour group, with a confidence interval of 1.15–1.87. Regression analysis did not show a statistically significant odds ratio for either death or minor complications.

Conclusion: There is a trend to increasing mortality and minor complications with a delay to surgery in hip fractures. A statistically significant increase in major medical complications and length of hospital stay with delay to surgery was found in our group. Regression analysis including age, gender and pre-existing medical comorbidity supported the significance of the increased risk of major medical complications with delay, adjusted for age, gender, and pre-existing medical comorbidity.

Michael Zlowodzki Ole Brink Julie Switzer Scott Wingerter James James David R Bruinsma Brad A. Petrisor Philip J. Kregor Mohit Bhandari

Purpose: Femoral neck fracture collapse and shortening has been a desired effect of parallel screw fixation to promote healing. While some degree of compression might be beneficial, it remains unknown whether the effects of uncontrolled femoral neck shortening leads to detectable functional impairment. We aimed to evaluate the effect of shortening and varus collapse after cancellous screw fixation of femoral neck fractures on patient functional status and quality of life.

Method: The databases of four University Hospitals were screened to identify patients with a healed isolated femoral neck fracture. Patients were contacted by telephone to complete Short-form 36(SF36) and Euroquol-5D(EQ5D) questionnaires (Primary outcome: SF36 physical functioning score[PF]). Femoral neck shortening and varus collapse were assessed by three independent reviewers blinded to functional outcome results based on the latest follow-up radiographs and categorized into three grades: None/Mild (within 5mm/5°), Moderate (5–10mm/5–10°), and Severe (> 10mm/> 10°). The minimal clinically important difference for SF36 PF score equals 12 points (1/2 of Standard deviation).

Results: Out of 660 patients screened at all four sites 70 met the inclusion criteria and were available for follow-up. The average follow-up was 20 months and an the average age was 71 years. Overall, there were 24/70 patients with none/mild femoral neck shortening, 25/70 with moderate shortening and 21/70 with severe shortening. Patients with severe shortening of their hip had significantly lower SF36 physical functioning scores (No/Mild vs. Severe shortening: 74 vs. 42 points, p=0.01). Similar important effects occurred with moderate shortening suggesting a gradient effect (No/Mild vs. Moderate shortening: 74 vs. 53 points). Some degree of varus collapse occurred in 39% of the patients and correlated moderately with the occurrence of shortening (r=0.66, p< 0.001).

Conclusion: A large proportion of displaced and undisplaced femoral neck fractures fixed with cancellous screws heal in a shortened position (66%) and varus (39%). The differences in function we observed represent patient important declines and suggest that uncontrolled sliding with cancellous screw fixation has limitations.

Sohail Bajammal Michael Zlowodzki

Purpose: The optimal treatment for displaced femoral neck fractures in patients aged 60–80 years is controversial. Orthopaedists that advocate for arthroplasty cite strong evidence that there is an increased revision rate with internal fixation. We aimed to explore patient preferences for the treatment of a displaced femoral neck fracture using a novel decision board approach.

Method: We developed a decision board presenting descriptions, expected outcomes, and potential complications of hemiarthroplasty and internal fixation for the treatment of displaced femoral neck fractures. 108 healthy volunteers were confronted with the scenario of sustaining a displaced femoral neck fracture and presented the decision board, then asked to state their preference for operative procedure, and describe the reasons for their choice.

Results: After application of the decision board with all outcomes presented for each alternative (internal fixation versus arthroplasty), 61/108 (56%) participants chose internal fixation over arthroplasty as their operative procedure of choice. Factors that contributed to this choice included: less blood loss (61%), shorter operation time (31%), less mortality (20%), and less invasive (18%). Participants who preferred arthroplasty (44%) did so primarily due to the lower re-operation rate (94%), better mobility (9%) and shorter hospital stay (4%).

Conclusion: Despite common surgeon preferences for arthroplasty, over half of participants preferred internal fixation due to less blood loss, shorter operative times, lower mortality, and less invasiveness. Surgeons should not assume that patients would prefer arthroplasty over internal fixation; the decision board can be an effective aid to incorporate patients’ preferences into the decision-making process.

Emil H. Schemitsch

Purpose: Tibial shaft fractures are a common injury. Tibial nailing is the current standard of care for these injuries, yet there is little information regarding patient based outcomes after nailing. We sought to determine the 1 year patient based outcomes and return to activities for patients with tibia fractures in a randomized trial of reamed and unreamed nail insertion.

Method: Over a 5 year period 1226 patients with 842 closed and 406 open tibial shaft fractures were enrolled in a randomized trial comparing reamed with unreamed tibial nail insertion in 29 trauma centers and had one year follow-up. The average age was 39±16 years and 74% were male. Patient based outcomes were determined using the validated Short Form-36 (SF-36) Physical Component Summary, the Short Musculoskeletal Functional Assessment (SMFA) Dysfunction Index, and a published return to activity questionnaire. Questionnaires were administered during the initial hospitalization to obtain pre-injury status, and then the same outcome instruments were used at the 2 week, 3 month, 6 month, and one year follow-up. Statistical analysis was performed comparing the groups with p < 0.05 designated as significant.

Results: There was no difference in any outcome parameter for any time frame between the reamed and unreamed groups. The 1 year SF-36 PCS (a 100 point scale with a mean of 50 in the general population, higher better) was 42.9±11 for the reamed group and 43.5±11 for unreamed group as compared with 52.5±9 for the reamed group and 53.1±9 for the unreamed group pre-injury. The SMFA Dysfunction Index (100 point scale, higher is worse) at 1 year was 18.2±17 for the reamed group and 17.5±17 for the unreamed group as compared with 7.9±13 for the reamed group and 7.7±13 unreamed group pre-injury.

Conclusion: In patients with tibial shaft fractures treated with intramedullary nails, patient based outcomes are not related to reamed or unreamed insertion. Patients sustaining tibial shaft injuries do not return to their pre-injury status based on validated outcomes assessments or return to activity by one year after injury.

Rita Selby William H. Geerts Hans J. Kreder Mark A. Crowther Lisa Kaus Faith Sealey Richard Jay Alex Kiss

Purpose: Among patients with isolated below-knee fractures, venography studies detect deep vein thrombosis (DVT) in 20 – 40%. The clinical relevance of these thrombi is unknown. We conducted the first randomized, double-blind, multicentre study designed to assess the effectiveness and safety of low molecular weight heparin compared to placebo in preventing CIVTE in patients with isolated fractures of the distal leg.

Method: Consecutive patients with fractures of the tibia, fibula or ankle requiring surgery were randomized to dalteparin 5000 U or placebo once daily SC within 72 hours of fracture for 14 + 2 days. Patients were screened using proximal duplex ultrasound at day 14, and followed up at 6 wks and 3 mos. Clinically suspected VTE was investigated using standardized algorithms with central, blinded adjudication.

Results: From August 2002 to October 2006, 134 patients were randomized to dalteparin and 131 to placebo. 98% of patients completed 3 mo follow-up. Overall, 5 patients had CIVTE (2 asymptomatic DVT, 2 symptomatic DVT, 1 nonfatal PE); 2 (1.5%) in the dalteparin arm and 3 (2.3%) on placebo (p=0.68). There were no major bleeds.

Conclusion: The overall incidence of CIVTE after surgically-repaired, isolated tibia, fibula and ankle fractures was so low (1.9%; 95% CI 0.7 to 4.7%), with no observed differences between dalteparin and placebo either for CIVTE or safety, that recruitment was stopped early. This study also demonstrates the large discrepancy between trials that utilize venographic and CIVTE outcomes.

Samuel Koo Jason Koh Todd Moen Gordon Nuber

Purpose: Recent advances in arthroscopic shoulder surgery has expanded the options available to surgeons repairing rotator cuff tears. There are now a variety of suture techniques that arthroscopists can use to fix tears but limited data on which might work best, particularly for double row techniques. The objective of this study was to compare the initial cyclic loading and load to failure properties of two arthroscopic double row fixation with that of the open double row technique.

Method: Thirty sheep shoulders were harvested and the infraspinatus tendons dissected free from all surrounding muscles and osseous attachments. Three double row stitch configurations (arthroscopic standard, arthroscopic mason-allen, open mason-allen) were performed and tested. The shoulders were then secured in a material testings machine and cyclically loaded between 5 and 100 N at 0.20 Hz for 10 cycles and then loaded to failure under displacement control at 1 mm/sec. Stiffness and ultimate load were measured and compared. The failure type, either through suture or anchor pull out, was also recorded.

Results: None of the specimens failed under cyclic loading. The ultimate load to failure was significantly higher for the open double row and the arthroscopic mason-allen compared to the standard double row technique. No significant differences in stiffness were found among the stitches. All failures occurred at the suture-tendon junction.

Conclusion: In this in vitro cadaver sheep study, the arthroscopic mason-allen and open mason-allen techniques had a significantly higher ultimate load to failure than the standard double row technique. Stitching methods that strengthen the tendon-suture interface can improve the strength of double row rotator cuff repairs.

Mohit Bhandari Paul J. Karanicolas Stephen D. Walter Diane Heels-Ansdell Gordon H. Guyatt

Purpose: Although blinding of outcome assessors is crucial to minimize bias in clinical trials, the majority of surgical trials do not blind these individuals in part due to practical difficulties inherent in surgical interventions. We devised and tested techniques to blind outcome assessors in trials of femoral neck fracture fixation.

Method: We developed three techniques to mask radiographs of femoral neck fractures fixated with cancellous screws or dynamic hip screws: Blackout, Subtraction, and Overlay. 50 orthopaedic trauma surgeons assessed 32 radiographs blinded with each of these techniques. We considered:

The ability to mask the surgeons (the proportion of radiographs in which the surgeons were able to correctly identify the implant and the Bang Blinding Index);

Surgeons’ ability to accurately rate the quality of reduction in blinded images;

Surgeons’ perceptions of difficulties rating the blinded images.

Results: All three techniques achieved low proportions of correct identification of cancellous or dynamic screws (14.9% for Blackout, 26.9% for Subtraction, 22.1% for Overlay) and high proportions of “don’t know” responses (72.3%, 48.4%, 52.8% respectively). The Bang Blinding Indices were close to 0 (perfect blinding) for all three techniques (−0.024 to 0.008). The interrater reliability of quality of reduction in the blinded images (ICC = 0.55 – 0.57) was similar to the reliability of the unblinded radiographs (ICC = 0.60). Surgeons perceived the Overlay images as much more difficult to rate in 6.9% of radiographs, compared with 9.7% of Subtraction images (p=0.25) and 28.0% of Blackout images (p< 0.001).

Conclusion: Three techniques of blinding radiographs of femoral neck fractures successfully mask surgeons to the type of implant fixated, do not compromise reliability of reduction ratings, and do not make the rating process substantially more difficult. Trialists should explore creative approaches such as these to blind as many individuals as possible when designing trials, and should incorporate rigorous approaches to testing the success of blinding.

Rita Selby William H. Geerts Hans J. Kreder Mark A. Crowther Maurice Bent Emil H. Schemitsch Peter Weiler Lisa Kaus Faith Sealey Richard Jay

Purpose: We conducted the first, multicentre, prospective cohort study to define the incidence of symptomatic venous thromboembolism (VTE) in patients with tibia and ankle fractures treated conservatively and relatively minor lower leg fractures. The reported incidence of deep vein thrombosis (DVT) using routine venography in patients with lower leg injury requiring cast immobilization is approximately 20–40%, which has lead to the routine use of anticoagulant prophylaxis for several weeks in many such patients. However the vast majority of venographically-detected DVTs are asymptomatic, distal thrombi whose clinical relevance is uncertain. Therefore venography is not the best outcome measure to assess the burden of clinically important VTE.

Method: Consecutive patients with tibia and fibula fractures (treated non-operatively) and patella and foot fractures, (treated operatively or conservatively) were assessed for eligibility at 5 Ontario hospitals. Patients were enrolled after informed consent within 96 hours of injury and were followed prospectively, by telephone, at 2, 6 and 12 weeks. Those with major trauma, active cancer, and previous VTE were excluded. Thromboprophylaxis was not allowed. Education regarding symptoms of VTE was provided at study entry and patients were asked about VTE symptoms at follow up. Suspected VTE was investigated in a standardized manner.

Results: From August 2002 to June 2005, 1200 patients were enrolled from 2446 consecutively screened patients. 98% of patients completed 3-month follow-up. The mean age was 45 years (16 to 93) and 60% were female. The most common fractures were fibular (39%) and most injuries were caused by falls (75%). 99 % of these fractures were unilateral. Most fractures did not require surgical repair (93%), and 82% of patients were immobilized by cast or splint for an average of 42 ±32 days. Overall, 7 patients had symptomatic, objectively confirmed VTE (2 proximal DVT, 3 calf DVT, 2 PE) with no fatal PE – an incidence of 0.6 % (95% CI 0.2 to 1.2).

Conclusion: Symptomatic VTE is an infrequent complication after these fractures without thromboprophylaxis. Therefore routine thromboprophylaxis is neither warranted, nor likely to be cost-effective in these patients. This study also highlights the significant discrepancy between clinical endpoint studies and studies using venography.

Robert G. McCormack Mauri L. Zomar Kostas P. Panagiotopoulos Richard E. Buckley Murray John Penner Bertrand H. Perey Graham C. Pate Thomas J. Goetz Michael S. Piper

Purpose: To compare failure rates, and patient functional outcomes, using the Dynamic Hip Screw (DHS) and Medoff Sliding Plate (MSP) for unstable intertrochanteric hip fractures.

Method: One hundred and sixty three consecutive patients with unstable intertrochanteric hip fractures, from three hospitals, were prospectively randomized to DHS or MSP. Inclusion and exclusion criteria were designed to focus on isolated unstable intertrochanteric hip fractures in ambulatory patients over age 60, without previous hip fractures or significant subtrochanteric extension. Patients were stratified by mental status and treating hospital. Randomization was performed intra operatively, after placement of a 135 degree guide wire. Follow up assessments were performed at regular intervals for a minimum of six months. The primary outcome was re-operation rate. The secondary outcome was patient function, using a validated outcome measure, the Hip Fracture Functional Recovery Score. Tertiary outcomes included: mortality, hospital stay, quality of reduction and mal union rate.

Results: 86 patients were randomized to DHS and 76 to MSP. The groups had similar patient demographics and pre fracture status (medical and functional). The patients had similar hospital course except there were more transfusions in the MSP group (2 vs. 1 unit). The quality of reduction was the same for each group but the operative time was longer in the MSP group (61 vs. 50 min). The rate of re-operation was low (3/86 in DHS and 2/76 in MSP) with no statistically significant difference. The indication for re-operation differed for the two groups as all three failures in the DHS group were related to screw cut out and both failures in the MSP arm were because of non union. The functional outcomes were the same for both groups with functional recovery scores at six months of 51% in the DHS arm and 49% in the MSP arm.

Conclusion: The two techniques produced similar results for the clinically important outcomes of the need for further surgery and functional status of the patients. For this challenging sub group of hip fractures, based on the equivalent results in this study either implant is a reasonable choice.

John N. Trantalis Richard S. Boorman Kristie D. Pletsch Tom Woods

Purpose: Arthroscopic repair of type II SLAP lesions can lead to improved clinical outcomes. However, the structural integrity of arthroscopically repaired type II SLAP lesions is unknown. The purpose of this study was to evaluate the clinical outcome of arthroscopically repaired type II SLAP lesions, and to evaluate the appearance of the repair on MRI arthrogram performed at least 1 year post-operatively.

Method: Between March 2003 and June 2006, the senior author performed isolated repairs of 25 type II SLAP lesions in 25 patients (18 male, 7 female) with a mean age of 40 +/− 12 years. The mean duration of symptoms was 32 months. None of the patients had undergone previous surgery on the affected shoulder. All tears were repaired using standard arthroscopic suture anchor repair to bone. All patients were reviewed using a standardized clinical examination by a blinded, independent observer, and using the ASES shoulder index and the simple shoulder test (SST). Paired and unpaired t-tests were used to determine significant differences between pre-operative and post-operative scores and re-torn and intact SLAP repairs, respectively. A p< 0.05 was considered statistically significant. In addition, 20 of the 25 patients were evaluated by MRI arthrography at least 1 year post-operatively which was interpreted by a musculoskeletal trained radiologist who was blinded to the patient’s clinical outcome.

Results: Follow-up was an average of 24.9 months. The mean ASES scores improved from 51.7 pre-operatively to 86.3 Follow-up was an average of 24.9 months. The mean ASES scores improved from 51.7 pre-operatively to 86.3 post-operatively (p< 0.0001) and the SST scores from 7.76 to 10.76 (p< 0.001). Twenty-two out of the 25 patients stated that they would have surgery again and there was a mean patient satistifaction of 8.7+/− 1.4 out of 10. Of the 20 patients who had post-operative MRI arthrograms, no patient had an obvious recurrent type II SLAP lesion, 8 patients had equivocal MRI arthrograms with a small amount of Gadolium insinuiating between labum and bone, and 12 patient had a completely intact superior labrum. There was no significant difference in ASES, SST and patient satisfication scores between patients with equivocal or competely intact repairs (ASES= 87.7 versus 85.4; p = 0.71; SST = 10.8 versus 10.8; p = 0.97; Pt satistifaction = 8.2 versus 8.8; p = 0.40). However, of the three patients who were not satisfied with the procedure (i.e. would not have the surgery again) two had postoperative MRI arthograms and both had equivocal SLAP repairs.

Conclusion: Clinical outcomes following arthroscopic repair of type II SLAP lesions showed statistically significant improvement in shoulder scores from pre to post-operative. MRI arthrogram results do not necessarily correlate with clinical outcome.

Ilya Voloshin A. David Davis Kenneth Morse Elizabeth Krall-Kaye Anthony Schepsis

Purpose: Controversy remains regarding the results of all arthroscopic rotator cuff repairs compared to the mini-open approach. The purpose of this study was to perform a comprehensive literature search and meta-analysis of clinical trials comparing the results of all arthroscopic rotator cuff repairs and mini-open rotator cuff repairs with two years of follow-up data.

Method: A computerized search of articles published between 1966 and July 2006 was performed using Medline and PubMed. Additionally, a search of abstracts from four major annual meetings each held between 2000 and 2005, was performed to identify Level I to III studies comparing the results of arthroscopic rotator cuff repair and mini-open repair. Studies that included follow-up of at least two years and included the use of one of four validated functional outcome scores used to study shoulder pathology were included in the present meta-analysis. All outcome scores were normalized to a 100-point scale to allow outcome comparison.

Results: Five studies that met the inclusion criteria were identified. There was no difference in functional outcome scores between the arthroscopic and mini-open repair groups. There was a trend toward fewer complications in the arthroscopic repair group, however, this did not meet statistical significance.

Conclusion: In studies with at least two years of follow-up data, there was no significant difference in functional outcome scores between the arthroscopic and mini-open rotator cuff repair techniques. The arthroscopic repair technique is a useful and successful alternative to the mini-open repair technique.

Peter B. MacDonald Sheila McRae Jeff Leiter Chris Walmsley

Purpose: Few studies have investigated the relationship between patients requiring rotator cuff surgery and their body mass index (BMI). The objective of this retrospective study was to evaluate the association between BMI and pre-operative pain and function in patients awaiting rotator cuff repair surgery as measured by the American Shoulder and Elbow Surgery (ASES) form and Simple Shoulder Score (SST). A second objective was to evaluate the role of several other factors in predicting patient pre-operative scores.

Method: Patients selected for this study were those who underwent arthroscopic rotator cuff repair performed by the same surgeon between 2002 and 2007. Their medical record included documentation of age, height, weight, smoking status, worker’s compensation status (WCB), and pre-operative ASES and SST scores. Correlation between BMI and ASES and SST scores was performed to determine the association between these variables. In addition, multiple stepwise regression was performed to assess the predictive value of other demographic and lifestyle factors.

Results: Fifty-four patients were included in the study (39 men, 15 women). No significant correlation was found between BMI and either ASES or SST scores. Based on multiple regression analysis, only WCB status was identified as a significant predictor of pre-operative ASES score (p=0.003) while sex, age, BMI, and smoking status were not. Patients with WCB claims had lower ASES scores than those without. Sex was found to have the strongest association with SST scores (r2 = 0.502) with men having greater SST scores than women. The model with the most significant value in predicting SST scores included sex, WCB and smoking status (r2 -= 0.640). Patients that did not fall under a WCB claim and were non-smokers had better SST scores pre-operatively.

Conclusion: BMI did not have a significant relationship to ASES and SST scores in patients awaiting rotator cuff repair surgery. A prospective study including pre- and post-surgical follow-up and a detailed analysis of the role between BMI and other demographic and lifestyle factors would be beneficial. Such a risk factor analysis may shed light on the indications for rotator cuff surgery or non-operative management, depending on the patient population.

Ryan T. Bicknell Cedric Pelegri Christopher Chuinard Lionel Neyton Pascal Boileau

Purpose: Partial rotator cuff tears are a frequent source of shoulder pain. At times, diagnosis is difficult and treatment unsuccessful. Historical treatment has involved open debridement when conservative treatment has failed. The purpose of this study was to evaluate the results of arthroscopic treatment of deep partial thickness tears of the supraspinatus tendon in patients over 40 years and to assess the healing radiographically.

Method: Forty-nine patients (mean age: 55 years) underwent treatment of a deep partial thickness tear of the supraspinatus tendon. Exclusion criteria: age < 40 years, associated instability, posterosuperior impingement or previous shoulder surgery. Patients were re-examined with a mean 32 months follow-up. For lesions involving less than 50% of the tendon thickness, an acromioplasty and either a debridement (n=39) or a side-to-side repair (n=3) was performed. For lesions involving greater than 50% of the tendon thickness (n=7), an acromioplasty and a trans-osseous repair was performed after completion of the tear. Twenty patients (41%) had an assessment of tendon healing by CT arthrogram, MRI or MR arthrogram, at a minimum 12 months post-operatively.

Results: Results were good or excellent in 90% of patients, and 94% were satisfied. The Constant score improved from 56 to 82 points (p< 0.0001) and the UCLA score improved from 15 to 30 points (p< 0.0001). Of the 31 patients employed preoperatively, three did not return to work; an occupational injury was predictive of a lower Constant score (p=0.02). Four out of 13 (31%) cases involving less than 50% of the tendon thickness healed and all cases (n=7) involving greater than 50% had healed.

Conclusion: Patients over 40 years with an isolated deep partial thickness tear of the supraspinatus tendon benefited both subjectively and objectively from arthroscopic intervention. For deep tears involving < 50% of the tendon thickness, resolution of pain and return to work is possible after acromioplasty and debridement. For deeper tears, completion of the tendon and reattachment to the greater tuberosity enables tendon healing.

Amr W. ElMaraghy

Purpose: Complete distal biceps tendon ruptures (DBTRs) require prompt surgical management for optimal functional and aesthetic outcome. Waiting for confirmatory diagnostic imaging can often delay timely surgical referral of these injuries. The need exists for a valid and reliable diagnostic tool to expedite appropriate referrals for surgery.

Method: Based on the hypothesis that complete distal biceps tendon rupture leads to an objectively measurable increase in the “biceps crease interval” (BCI) due to proximal retraction of the musculotendinous complex, three independent examiners established “normal” biceps crease intervals (N-BCI) for 80 males (average age = 43 years) with no history of biceps injury. Given acceptable inter-rater reliability (ICC > 0.70), a mean N-BCI value was established and a normal biceps crease ratio (N-BCR) between right and left arms was calculated. Correlations with arm dominance, biceps circumference, and age were determined. Diagnostic N-BCI and N-BCR thresholds were applied to 23 consecutive patients presenting with a possible complete DBTR to determine the diagnostic value of the BCI Test. A definitive diagnosis was confirmed at surgery and/or by radiographic imaging.

Results: The BCI Test had acceptable inter-rater reliability (ICC= 0.794, p = < 0.001). The mean N-BCI for both dominant and non-dominant arms was 4.8 +/− 0.6 cm. The mean N-BCR was 1.0 +/− 0.1. Applied to an injured population, using a diagnostic threshold of two standard deviations above “normal” values (BCI > 6.0 cm, BCR > 1.2), the BCI Test had a sensitivity of 92% and a diagnostic accuracy of 93%.

Conclusion: The BCI Test is an objective, valid and reliable test that can be used by clinicians to facilitate rapid diagnosis and surgical referral of suspected complete DBTRs.

Mohan Krishna Pullagura Joseph Pooley Aysha Rajeev Mainudden Bhavikatti

Purpose: The purpose of this study is to evaluate the arthroscopic findings in patients who presented with persistent lateral elbow pain despite conventional conservative measures, with special regard to diagnosis specific results. The controversy regarding the etiopathogenesis, whether intraarticular, extraarticular or both continues to exist.

Method: This is a retrospective review of 280 arthroscopies of elbow in 262 patients over a period of 6 years with a minimum follow-up of 6 months. All of them are therapeutic procedures involving ECRB release, excision of plica, synovectomy or debridement of the joint. The functional outcome was assessed and recorded independently by two experienced upper limb physiotherapists using the Mayo elbow performance score.

Results: Dominant hand was involved in 68% of the cases. The average age was 54 years. Isolated pathology such as common extensor inflammation was identified in 138 (49%), synovial plica in 24 (8%) and degenerative changes confined to lateral compartment with normal appearance of articular cartilage of medial compartment is noted in 31 (11%). In the rest mixed pathology with various combinations were identified.

Conclusion: Good to excellent results were seen in those with isolated common extensor inflammation and poor outcomes were noted in 20 (7%) of patients and the common intraoperative finding seen was degenerative changes of radiocapitellar joint. This was found to be statistically significant.

Robert W. Wysocki Mark S. Cohen

Purpose: The purpose is to evaluate the clinical outcome of patients who underwent excision of motion-limiting radioulnar heterotopic ossification (HO) as a complication of a distal biceps tendon repair. The hypothesis is that there are no measurable clinical losses that persist after excision.

Method: Between 1996 and 2005, eight consecutive patients were identified. All were treated with heterotopic ossification excision using a standard surgical technique, a single dose of postoperative radiation, four weeks of indomethacin, and a standard rehabilitation protocol. These individuals were studied and compared to a matched cohort of eight patients who underwent a distal biceps tendon repair with a similar surgical technique that was uncomplicated. At minimum follow-up of one year, all patients in both groups completed the Disabilities of the Arm, Shoulder and Hand (DASH) outcomes questionnaire, were tested for range of motion in elbow flexion/extension and forearm supination/pronation, and underwent biceps isokinetic dynamometry strength testing including elbow flexion and forearm supination. Both peak strength as well as muscle fatigue were quantified. Range of motion and strength comparisons were made both between groups and side-to-side within each group.

Results: There were no patients lost to follow-up. At mean follow-up of 56 months, there were no cases of nerve palsy, recurrence, or other complications. All patients in the HO group returned to their original occupation without restrictions. Mean arc of forearm rotation in this group increased from 19 to 151 degrees (p=0.01), but pronation (65 degrees) was less than the unaffected arm (p=0.01). There were no side-to-side differences in motion within the control group, or differences in peak strength or fatigue within either group. When comparing the two groups, there was a trend towards worse functional outcomes on DASH in the HO group than the controls (p=0.09). No differences were identified between the HO and control groups with respect to isokinetic torque, endurance strength or range of motion.

Conclusion: When patients develop motion-limiting heterotopic ossification after distal biceps tendon repair, surgical resection can safely lead to a functional recovery of elbow and forearm strength and motion. Level III Evidence, Case-control

Sean Comstock John C. Hyndman J. Lorne Leahy Ron El-Hawary P. Chris Cook

Purpose: To describe the Halifax anterior-posterior kyphectomy, and report on a series consecutive patients.

Method: Twenty-two patients received a Halifax kyphectomy over a 23 year period. Patient charts were examined, and radiographs measured pre- immediately post- and at final follow up. Cobb’s method was used to determine kyphosis angle. The procedure itself involves an apical kyphectomy, and cord transection if necessary, followed by the insertion of two rods distally and anteriorly in the vertebral bodies. This is followed by sublaminar wires superiorly and reduction of the kyphosis. Data was analysed to attempt to find a correlation between age, deformity, OR time, length of stay and maintainence of correction.

Results: Mean age was 7.59 years (2–17); mean pre-op kyphosis was 123.19 degrees (79–163); post-op 40.43 degrees (13–92); mean correction of 82.29 (39–153). Mean follow-up was 6.38 years (0–14); mean kyphosis at follow-up was 60.24 degrees (14–126), mean final correction of 63.43 degrees (−37–162); mean loss of correction 19.33 degrees (−9–76). The average OR time was 247.86 minutes (180–345); EBL 765cc (140–2100) and length of stay 13.68 days (1–57). Eight patients required hardware removal, and two of these required revision surgery. The other six patients maintained correction without hardware, and did not require re-operation. One patient had a rod fracture, but did not require revision or removal. Twelve patients had no complications. There was one intra-operative mortality.

Conclusion: The Halifax kyphectomy is a safe, effective treatment for kyphosis in myelomeningocele patients. Outcomes in this series are comparable to the available literature.

Daniel J. Sucato David A. Podeszwa

Purpose: Unstable slipped capital femoral epiphysis (SCFE) can result in a high incidence of avascular necrosis (AVN) and residual deformity leading to femoral acetabular impingement (FAI). Surgical hip dislocation with open reduction and internal fixation (ORIF) has been proposed as a surgical method to avoid or limit these complications.

Method: A prospective consecutive series of patients who presented with an unstable SCFE and underwent a surgical hip dislocation/ORIF were reviewed. The procedure entails urgent arrival to the operating room, a surgical dislocation procedure to gain full access to the proximal femur, removal of the posterior and medial callus with necessary shortening of the femoral neck to anatomically reduce the femoral head without tension on the vasculature.

Results: There are 15 patients in this series with a minimum of 1 year follow-up. Average age was 12.5 years at the time of presentation, 10 males and 5 females. Surgical dislocation was performed at a mean of 29.1 hours from the traumatic event. The surgical procedure averaged 135.5 minutes, with an average blood loss of 220ccs. Fourteen patients have no evidence of AVN while one patient with AVN was due to a surgical step not performed in the remaining hips. Normal anatomic position of the epiphysis was achieved in 11 of 15 patients while the remaining 4 had mild posterior angulation averaging 6.2 degrees. Average hip flexion was 114°, internal rotation 22°, external rotation 35°. Two patients required reoperation for broken screws (both 4.5mm cannulated screws).

Conclusion: Surgical dislocation with removal of medial and posterior callus and shortening of the femoral neck can reduce the femoral head to a near anatomic position to avoid FAI and appears to result in a very low incidence of avascular necrosis. A single patient with AVN was the result of technical issue which can be avoided.

Paul John Moroz Stephen P. Kingwell

Purpose: A single level spine fracture can be dangerous, however a second spine fracture at a different level can add complexity to patient management, and if missed, can result in a significant adverse outcome. Higher rates of multiple noncontiguous spinal injury (MNCSI) have been reported in patients who die from injuries, and with more unstable spinal injuries. The reported incidence in adults is 1.6–34%, but to our knowledge there are no studies examining multiple spine injuries in a pediatric population.

Method: A retrospective review of charts at an academic pediatric level 1 trauma center over a 15 year period identified a population with MNCSI.

Results: Twenty five (11.8%) out of 211 patients were identified with MNCSI and complete charts and radiographs. The mean age was 10.7 years old. MVC (motor vehicle collision) was the most common mechanism of injury for ages 0–9, while a fall was most common for ages 10–17 years. The mean number of vertebral levels injured was 3.2 and the most common region was the thoracic spine. Patients had a mean of 5.4 (range 1 to 22) intact vertebral levels between injuries. Twenty-four percent of patients with MNCSI had a neurologic deficit compared to 9.7% in patients with single level or contiguous injuries. This was statistically significant; risk ratio was 2.48 [1.09, 5.65]. Seven (78%) of 9 patients aged 0–9 suffered an associated injury; most commonly a visceral injury. The mortality rate was 8.0% in patients with MNCSI compared to 2.7% in patients with a single level injury.

Conclusion: We report a 12 % incidence of MNCSI in a pediatric trauma population. Children with NCSI were more likely to suffer neurologic injury than with a single level injury. Younger patients with MNCSI’s had a high rate of associated injuries. A higher mortality rate was seen in patients with MNCSI (not statistically significant). MNCSI’s can occur in conjunction with SCIWORA’s in the flexible pediatric spine. Clinicians must be aware of the incidence of NCSI’s in children, as well as their associations.

Alison Rozansky Mark Adamcyzk William Schrader Patrick Riley Dennnis S. Weiner Halley Wasserman Melanie Morscher Kerwyn Jones

Purpose: Waterproof casts have been shown to be a safe and effective means of immobilization in children with minimally displaced fractures. The purpose of this study was to determine if waterproof Gore-Tex-lined casts are as effective as traditional cotton-lined casts in the immediate postoperative period after closed reduction of displaced distal radius fractures in children.

Method: We performed a retrospective review of distal radius fractures that underwent closed reduction and application of a long-arm cast between June 2004 and December 2006. A total of 124 cases were included (55 Gore-Tex; 69 traditional cotton-lined). The primary outcome measure was redisplacement in the cast. The cast index was also used to assess the quality of cast molding. Data was analyzed using repeated measures ANOVA. Power analyses were also conducted.

Results: There were no significant differences between the two groups with regards to translation of the radius or angulation of the radius on anterior-posterior (AP) and lateral radiographs at the time of injury, postreduction, or cast removal. Redisplacement as measured by the change in translation of the radius and angulation of the radius on AP and lateral radiographs from the time of reduction to cast removal was also not significantly different between the two groups. The mean cast index for the Gore-Tex and traditional cotton-lined groups was 0.882 and 0.873 respectively, which was not a significant difference.

Conclusion: A waterproof Gore-Tex-lined cast will maintain fracture reduction as well as a cotton-lined cast for closed reductions of distal radius fractures in children in the immediate postreduction period. Waterproof casts also provide extensive benefits to the patient with regards to bathing, hygiene, and participation in aquatic activities

Panagiotis Peter Glavas Jean-Marc Mac-Thiong Stefan Parent Jacques A. de Guise Hubert Labelle

Purpose: To determine the reliability of six measurement techniques for lumbosacral kyphosis.

Method: Using custom computer software, four raters evaluated 60 standing lateral radiographs of the lumbosacral spine during two sessions at a one week interval. The sample size consisted of 20 normal, 20 low and 20 high grade spondylolisthetic subjects. Six parameters were included for analysis: Boxall’s slip angle; Dubousset’s lumbosacral angle (LSA); the Spinal Deformity Study Group’s (SDSG) LSA; dysplastic SDSG LSA; sagittal rotation (SR); kyphotic Cobb angle (k-Cobb). Intra- and inter- rater reliability for all parameters was assessed using intra-class correlation coefficients (ICC). Correlations between parameters and slip percentage were evaluated with Pearson coefficients.

Results: The intra-rater ICC’s for all the parameters ranged between 0.81 and 0.97 and the inter-rater ICC’s were between 0.74 and 0.98. All parameters except sagittal rotation showed a medium to large correlation with slip percentage. Dubousset’s LSA and the kyphotic Cobb angle showed the largest correlations (r=−0.78 and r=−0.50, respectively). Sagittal rotation was associated with the weakest correlation (r=−0.10). All other parameters had medium correlations with percent slip (r=0.31 to 0.43).

Conclusion: All measurement techniques provided substantial to almost perfect inter- and intra- rater reliability. Dubousset’s LSA showed the strongest correlation with slip grade. However, this parameter does not reflect the local dysplastic changes that occur in lower L5 and upper S1 endplates. A longitudinal study evaluating the best suited parameter for predicting the risk of progression and response to surgical treatment is warranted.

Thomas Scharschmidt Dennis Weiner Robin Jacquet Elizabeth Lowder Tyson Schrickel William Landis

Purpose: Slipped capital femoral epiphysis (SCFE) is a poorly understood condition impacting adolescents. Its consequences can be severe, even where there is early recognition and treatment is implemented. Prior studies have suggested that the etiology may be related to abnormal collagen comprising the growth plate cartilage, but no investigations have analyzed collagen or other structural proteins on a molecular level in the affected tissue. This study evaluates expression of mRNA for key structural proteins obtained from growth plate chondrocytes of patients suffering SCFE.

Method: The work utilizes laser capture microdissection (LCM) techniques followed by reverse transcription polymerase chain reaction (RT-PCR) to determine if a change or abnormality in type II collagen and/or aggrecan gene expression may be involved in weakening the physis, a characteristic of the pathology. With these techniques, correlation of chondrocyte spatial location and gene expression can be made to provide greater insight into this pathology and a more complete understanding of growth plate biology in general.

Results: Downregulation of both type II collagen and aggrecan was found in the growth plates of SCFE subjects when compared to age-matched controls. Expression levels for type II collagen mRNA of SCFE patients were less than 14% of their counterpart controls. SCFE aggrecan levels averaged only 26% of control expression.

Conclusion: The significant decreases in type II collagen and aggrecan expression would drastically affect the quantity, distribution, and organization of both components in SCFE growth plates. Such abnormal changes may contribute to the cause of a slip although possibly they may be the result of a slip. This is the first study using novel LCM and RT-PCR to determine specific gene expression levels for two principal structural proteins comprising the growth plates of human subjects suffering SCFE.

Christine Marie Alvarez Mary Devera Vince Lau

Purpose: The purpose of this study is to report on the outcomes of children with ITW who received Botulinum A Toxin (BTX-A) as an adjunct treatment to manipulations/casting and maintenance protocol.

Method: ITW severity was classified using gait analysis and defined by the absence of 1st ankle rocker, early 3rd rocker and an early and increased first ankle moment1. Subjects who met the three severity criteria received a single BTX-A injection into both gastrocsoleus and placed immediately in below-knee casts. Casts were changed two weeks later for a total casting period of four weeks. Subjects then entered a maintenance protocol involving use of night splints or articulated ankle-foot-orthotics. Outcome measures collected at all follow-up visits were ankle dorsiflexion with knee in 90° flexion (DFF) and extension (DFE).

Results: Thirteen subjects with severe bilateral ITW participated. Subjects were followed for an average of 48 weeks (range 7 – 168 weeks) post BTX-A injection. Given the variability in subject outcomes, analyses and reporting were stratified according to subjects’ right and left feet. At day of BTX-A, right foot DFF/DFE were 1.7° ± 14.4 and −1.5° ± 13.0 and mean left DFF/DFE were −1.5° ± 12.8 and −6.5° ± 12.1. Immediate improvement following BTX-A (2 weeks) were seen as right foot DFF/DFE were 14.1° ± 10.0 and 6.3° ± 7.7 and left DFF/DFE were 9.6° ± 14.1 and 3.9° ± 10.6. At 4 weeks, right DFF/DFE were 16.6° ± 9.5 and 11.7° ± 9.1 and left DFF/DFE were 13.1° ± 8.6 and 7.3° ± 8.3. At the half-life of BTX-A (12 weeks), right DFF/DFE were 15.2° ± 12.2 and 10.8° ± 10.5 and left DFF/DFE were 15.8° ± 12.4 and 13.0° ± 11.6. At follow-up visits, correction was maintained as right DFF/DFE were 15.6° ± 9.1 and 10.4° ± 10.3 and left DFF/DFE were 16.9° ± 11.2 and 9.8° ± 10.7.

Conclusion: This is the first study to show early outcomes (improved DFF/DFE) following BTX-A injections in ITW and provides evidence for obtaining and maintaining the correction from a single BTX-A injection over a short-term follow-up period.

Hiroko Matsumoto Michael G. Vitale Jaime A. Gomez Joshua E. Hyman Brian E. Kaufman David P. Roye

Purpose: The current literature lacks a truly comprehensive examination of the use of a valgus osteotomy to treat osteonecrosis of the femoral head and Perthes disease in the pediatric and adolescent population. Owing to the severity of the pathology, a retrospective examination of the success of valgus osteotomies in treating avascular necrosis and Perthes disease in children and adolescents is warranted.

Method: Twenty-four patients with diagnosis of osteo-necrosis of the femoral head or Perthes disease treated between 1995 and 2007 with a proximal femoral valgus osteotomy were identified. The causes of avascular necrosis were Perthes (N=14, 60.9%), slipped capital femoral epiphyses, (N=4, 17.4%), femoral neck fracture (N=2, 8.7%), hip septic arthritis (N=2, 8.7%) and developmental delays and idiopathic osteonecrosis (N=1, 4.3%). The average age of receiving a femoral valgus osteotomy was 10± 3.6 years. The average age at follow-up was 12.2± 4 years, mean time of follow-up from the initial valgus osteotomy to last assessment was 23± 15.3 months.

Results: Postoperative pain improved significantly compared to preoperative pain (p=.002). Seventy five percent of patients (n=9) who had limitations in their daily activities preoperatively reported that they no longer experienced them after the treatment. External rotation (p=.005) and abduction (p=.003) improved significantly at follow up. Postoperative Ficat & Arlet classification was significantly better when compared to the classification before valgus osteotomy (p=0.007). Univariate analysis showed that sixty percent of patients (n=6) who had Perthes had improved in their Ficat & Arlet stage whereas one (14.3%) patient with a different diagnosis improved (p=.082). Complications from the surgery were reported in 5 of the 23 (21.7%) cases.

Conclusion: The results of this study suggest that proximal femoral valgus osteotomy is a safe and effective treatment method for osteonecrosis of the femoral head in the pediatric population. Perthes patients improved their femoral head shape more than all other etiologies; there was a trend toward statistical significance in this change. Proximal femoral valgus osteotomy may improve pain and activity limitations in children with osteonecrosis of the femoral head. It is also effective at improving range of motion and femoral head x-ray appearance of the femoral head for these children.

Christine Marie Alvarez Mary Devera Harpreet Chhina Alec Black

Purpose: The purpose of this study is to describe the pedobarographic (plantar pressure) profiles of normal children across all ages, with specific focus on young children (< 6 years) and explore age-related changes in foot pressure patterns.

Method: The Tekscan HR Mat system and Research Foot Module were used in a protocol involving a dynamic test of 146 normal children (age range 1.6–14.9 yrs). Using previously described methods1, relative force and timing data were obtained across five foot segments (heel, lateral midfoot, medial midfoot, lateral forefoot, and medial forefoot). An exploratory approach using analysis of variance (ANOVA) techniques followed by Scheffe post-hoc tests were conducted to determine if there were any age-related differences in foot pressure profiles in children across a priori pedobarograph variables: % of stance at initiation at the heel; % of stance at initiation at the medial midfoot; maximum % force at the heel; and maximum % force at the medial midfoot.

Results: Differences in foot force and timing profiles were distinguished across three age groups: 1) Group 1: 5 years. Data shows that with increasing age, force at the heel increases (Group 1: 61.4, Group 2: 66.9, Group 3: 71.9; p-value=0.019). Data also shows that force at the medial midfoot decreases with increasing age (Group 1: 17.7, Group 2: 8.8, Group 3: 4.7; p-value=0.0). Younger children also demonstrate early initiation of force at the medial midfoot compared to older children (Group 1: 5.9, Group 2: 33.5, Group 3: 44.8; p-value=0.0). In children > 5 years, there are no changes in foot forces or timing of forces.

Conclusion: This is the first study to provide a comprehensive description of the pedobarographic profiles of a large sample of normal children across all ages, with specific focus on the young child. Quantifying foot pressure of children will have relevance to clinical decision making.

Thomas P. Sculco Stavros G. Memtsoudis Alejandro González Della Valle Melanie C. Besculides Licia Gaber

Purpose: To determine mortality and morbidity for bilateral total knee replacment compared to unilateral knee replacement and revision total knee replacement using the National National Hospital Discharge Survey to include large numbers of patients and look at outcomes.

Method: We analyzed nationally representative data to elucidate the demographics, comorbidities, hospital stay, in-hospital complications and mortality of patients undergoing BTKA and compared them with those of patients undergoing UTKA and revision TKA (RTKA). Data in the National Hospital Discharge Survey on hospital discharges with procedure codes for BTKA, UTKA and RTKA between 1990 and 2004 was analyzed. The demographics, comorbidities, in-hospital stay, complications and mortality were studied. We identified 4,169,489 discharges (153,259 BTKAs; 3,677,161 UTKAs; and 339,069 RTKAs).

Results: Patients undergoing BTKA were younger (1.5 years) and had a lower prevalence of comorbidities for hypertension (vs. UTKA), diabetes, lung disease, and coronary artery disease (vs. UTKA and RTKA). The length of hospitalization was 5.8 days for BTKA, 5.28 for UTKA, and 5.41 for RTKA. Despite similar length of hospitalization, the prevalence of procedure related complications was higher for BTKA (14.17%+/−0.76 (SE)) than for UTKA (9.01%+/−0.17) and RTKA (9.84%+/−0.57). In hospital mortality was highest for BTKA patients (BTKA: 0.47%+/−0.15%; UTKA: 0.30%+/−0.03; RTKA: 0.27%+/−0.09).

Conclusion: Despite younger age and lower comorbidity burden, patients undergoing BTKA had an approximately 1.6 times higher rate of procedure related complications and mortality compared to those undergoing UTKA. Outcomes for RTKA patients for most variables were similar to those for UTKA. In a multivariate analysis, BTKA, advanced age and male gender were independent risk factors for complications and mortality following TKA surgery.

David P. Roye Jaime Gomez Michael G. Vitale Joshua E. Hyman Hiroko Matsumoto David Feldman Salih Marangoz Harold P. vanBosse Debra A. Sala Matthew Stein

Purpose: To describe the clinical outcomes of adolescent patients, treated with hip distraction arthroplasty for avascular necrosis (AVN) of the femoral head. Outcomes were examined in order to better understand the usefulness and indications of performing hip arthrodia-stasis in this patient population.

Method: Retrospective review was performed on thirty-one hips with femoral head AVN treated with hip distraction arthroplasty. Mean age at treatment was 14.2 years. Preoperative and follow-up pain, and physical limitations, as well as follow-up range of motion (ROM) were assessed.

Results: Follow up assessment was obtained at 18.3 years of age. Time of follow up was 55.3 months after distraction. The etiologies of AVN were: 11 Slipped Capital Femoral Epyphysis (SCFE); 5 Idiopathic AVN; 3 with hip dysplasia; and 12 others. There was a significant difference in pain preoperatively and postoperatively (p< .001), the majority of patients (79.5%, n=23) had less pain after the treatment. Multivariate regression model demonstrated that patients with SCFE were likely to have less improvement in pain than patients with other etiologies (odds ratio: 24.8; p=.035). All patients had activity limitations before the treatment; at the postoperative assessment more than half of our patients (n=15) reported no limitations in their activities. Nine patients had minor complications with the fixator. At follow up, 5 (16.1 %) patients converted to total hip replacement or arthrodesis.

Conclusion: Hip distraction arthroplasty in adolescent patients with symptomatic AVN reduces the amount of pain and limitation in daily activities, at a follow up of 4.6 years. Arthrodiastasis is not the final solution to AVN, with longer follow up patient’s symptomatology increases. Patients with AVN secondary to SCFE do not beneficiate of this procedure as much as other patients do. Hip distraction is a safe and appropriate procedure to perform in these patients. The procedure might be able to delay definitive surgical procedures at an early age, restoring function and improving the patient s quality of life.

Cheryl Hubley-Kozey Michael J. Dunbar Nick Hill Kevin J. Deluzio

Purpose: To test for a decrease in knee musculature co-activation at one- and two-year post total knee replacement (TKR) compared to pre-TKR values.

Method Thirty men and 35 women with knee osteoarthritis (OA), after providing informed consent, participated in this study. Surface electromyograms (EMG) recorded the activation of seven muscle sites (rectus femoris, vastus lateralis and medialis, lateral and medial hamstrings, lateral and medial gastrocnemius) while subjects ambulated, at a self-selected velocity, along a six-meter walkway; one week prior to TKR surgery, and one- and two-years post-TKR. Linear enveloped EMG waveforms, amplitude normalized to 100%MVIC and time normalized to 100% of the gait cycle, were entered into a principal component analysis model [1]. A two-factor (pre-post, muscle) repeated measures ANOVA was applied to test statistically significant main effects (pre-post, muscle) and interactions (alpha = 0.05).

Results: The mean age, mass and height pre-TKR were 63.4 years, 91.4 kg and 1.69 m, respectively. Forty seven and 25 subjects completed the one- and two-year follow up, respectively. Walking velocity increased from 0.9 m/s pre-TKR to 1.1 m/s for both one- and two-year post TKR. Four principal components explained 89% of the variance in the waveform data. PC1 (60% of the variance), associated with co-activation throughout the entire stance phase, was found to be statistically significant (p< 0.05). The post hoc analysis revealed no significant differences between one- and two-year post-TKR PC1 scores, but the two vasti muscles and lateral hamstring had significantly lower PC1 scores post-TKR compared to pre-TKR values. There were significant differences among muscles with the two vasti muscles higher pre-TKR compared to all other muscles, and lateral hamstring higher pre-TKR than the remaining four muscles.

Conclusion: PC1 captured a co-activation pattern illustrating muscle activation during the majority of the stance phase of gait for the vasti and lateral hamstring muscles. This pattern, previously shown in severe OA gait [1], is considered an adapted response to the pain and joint instability associated with latter stages of OA progression. These findings support that the neuromuscular control strategies are altered within one year with no additional change for the two year post-TKR measures. These results support a more efficient neuromuscular control strategy post-TKR and perhaps an associated decrease in metabolic cost and an improvement in function.

Kathy Gooch Tracy Wasylak Leslie Dort Doug Smith Hoa Khong Julie Hibbert Lu Liu Cyril B. Frank D. William C. Johnston Timothy J. Pearce Ronald F. Zernicke

Purpose: Total hip and knee replacements are recognized as effective surgical interventions for severe arthritis. Increasing demand for these services has led to increasing waits for both consultation and surgery. The Alberta Orthopaedic Society, with the Alberta Bone and Joint Health Institute, the Calgary Health Region, the Capital Health Region, the David Thompson Health Region and Alberta Health and Wellness carried out an analysis and an evidence based redesign of the care continuum for hip and knee replacement surgery in an effort to reduce wait times and improve the quality of service for patients.

Method: The study design was a randomized, controlled trial. Consenting subjects were randomized to receive care through either the new care continuum or the existing “current conventional approach”.

Results: During the 12 month study, 1570 patients received surgery. The mean wait for an orthopaedic consultation for intervention patients was 106 days compared to 200 days for the control patients. The mean wait for hip or knee surgery for intervention patients was 157 days compared to 408 for the control patients. Further analysis of the data using a generalized linear model utilizing negative binomial regression indicated that several patient characteristics were associated with a shorter/longer wait times. The less the severity of the disease pre-surgery was associated with a longer wait for a consult (IRR=1.01, p=< 0.001). Longer waits for surgery were statistically associated with less disease severity (IRR=1.004, P=0.019), documented delay (due to non-arthritic medical concerns or patient request for delay, IRR=1.61, p=< 0.001), increased comorbidity (IRR=1.03, p=0.015), and smoking (IRR=1.30, p=0.020).

Conclusion: The results of this study confirm that a redesigned joint replacement new care continuum with a standardized primary care referral process to centralized, specialized joint replacement clinics without established backlogs can help reduce wait times in Canada.

David Wilson Michael J. Dunbar Allan Hennigar

Purpose: To investigate the effect that gender may have on the RSA defined migration pattern of cemented and uncemented tibial components in total knee arthroplasty (TKA).

Method: 70 patients with primary osteoarthritis of the knee were randomized to receive a Nexgen uncemented Trabecular Metal (TM) monoblock tibial component (n=37; 20 female; mean age=66 years; mean BMI=32) or cemented cobalt chrome modular tibial cmponent (n=33; 19 female; mean age=65 years; mean BMI=33). The same design of posterior stabilized tibial component was used in all cases. Four experienced knee surgeons followed a standardized surgical technique (PCL resection, patella resurfacing, RSA bead placement in poly-ethylene and tibia) and post-operative protocol (CPM as tolerated, no drains, WBAT). Within 4 days of surgery and at 6, 12 and 24 months post-operatively patients underwent bi-planar x-rays. RSA analysis was performed with MB-RSA (MEDIS, Leiden). Results were reported as maximum total point motion, and 6 degrees of freedom translations and rotations. A repeated measure ANOVA was used to test for differences and all statistical analysis was performed using Minitab V.14 (Minitab Inc, State College, PA, USA).

Results: Highly significant differences were seen in the migration patterns in females between the TM and cemented tibial components. Females with the TM implant tended to rotate internally (0.29° vs. −0.16°, p< 0.0001), tilt posteriorly (−0.49° vs. 0.01°, p< 0.0001) and subside (−0.357mm vs. 0.00mm, p< 0.0001) compared with the female subjects with the cemented implant. In the male group, only subsidence was different between the TM and cemented groups (−0.344mm vs. −0.01mm, p< 0.0001).

Conclusion: Uncemented TM implants in females tended to tilt posteriorly, rotate internally and subside. Uncemented implants in males tended only to subside. The increased tilting and rotation detected in females could be due to lower BMD or to mismatching between the shape of the female proximal tibial and the tibial component. These results may have implications for the current use of uncemented implants in females and for future design of uncemented implants for the female population.

Alison Klika Wael K Barsoum Bishoy Gad Joe Styron Karen Green Boris Bershadsky Matthew Pifer

Purpose: The current health care climate encourages an early discharge directly home. Efforts to increase efficiency and decrease length of stay require accurate pre-planning of patient discharge following total joint arthroplasty (TJA). The purpose of this study was to develop and evaluate an easily administered form to preoperatively predict patient discharge disposition following TJA.

Method: A form was generated by a multidisciplinary group of clinicians which identified a set of preoperative factors relevant to patient discharge including age, gender, body mass index, comorbidities, preoperative ambulatory status, projected postoperative weight bearing, home environment and location, and caregiver assistance. Data were collected from a retrospective review of 516 medical charts for patients that had undergone primary total knee arthroplasty (TKA) (n=103), revision TKA (n=104), bilateral TKA (n=102), primary total hip arthroplasty (THA) (n=106), and revision THA (n=101). A stepwise multinomial logistic regression model was used to identify predictors of discharge to a skilled nursing facility (SNF), rehabilitation facility, or home, using SPSS version 11.5 statistical software (SPSS Inc., Chicago, IL).

Results: Patients were more likely to be discharged to either a SNF or rehabilitation facility if they underwent bilateral TKA (p< 0.001); were female (p< 0.001), have their heart disease monitored (p=0.003); or are older (p< 0.001). Patients are more likely to be discharged home if preoperatively they are capable of independent ambulation in the community (p=0.014). Patients discharged to either a SNF or rehabilitation facility were not significantly different except patients undergoing bilateral TKA were more likely to be discharged to a rehabilitation facility (p< 0.001).

Conclusion: We identified factors associated with discharge to a SNF, rehabilitation facility, or home following elective joint replacement surgery. With further validation, this model may be a useful tool for preoperatively predicting a patient’s discharge disposition, which is valuable to the hospital, clinicians, patients, and families in efficiently preparing for postoperative care.

Michael J. Dunbar Allan Hennigar David Wilson J. David Amirault Gerald Reardon Michael Gross

Purpose: Porous metal technology may have significant impacts on implant fixation and long-term survival due to their high co-efficient of friction and similarity to trabecular bone in morphology and mechanical behaviour. While promising, the in vivo mechanical behaviour and micromotion at the interface has not previously been reported on. We report on the 2-year results of an RCT using radiosterometric analysis (RSA) to asses a porous metal (PM) monoblock tibial component.

Method: Patients undergoing TKA were randomized to receive a either the PM (n=34) or the cemented tibial component (n=33). A standardized protocol was used for intra and post-operative factors. RSA exams were obtained postoperatively within 4 days of surgery and at 6, 12 and 24 months. One patient was excluded due to an intraoperative complication, and four others were lost to follow-up due to poor bead visibility or morbidity. Standard subjective outcome measures were applied.

Results: There were no revisions in either group. The PM group exhibited two distinct migration patterns. One group stabilized immediately with similar migration to the cemented cases (0.38 vs. 0.46 p=0.4). A subset of 6 PM cases demonstrated significantly higher initial migration (mean=2.01mm, p< 0.01) but appeared stable at 2 years. In addition, 3 of the 6 high migration cases manifested independent bead subsidence. This was determined to be due to PM plate deformation. Two cemented cases were considered at risk for early failure due to aseptic loosening because of RSA migration pattern. There were no differences between groups in the subjective health outcome measures.

Conclusion: A subset of PM components demonstrated high early migration followed by stabilization. It appears that some of these PM components deformed under load, most often in the posteromedial corner, perhaps as a result of malalignment or ligament imbalance. The implications of this finding are yet to be determined.

Richard W. McCalden Juliana T. Marr Robert B. Bourne Steven J. MacDonald

Purpose: The purpose of this study is to compare the clinical results of a standard polyethylene tibial insert versus the high flex polyethylene tibial insert component designs of a posterior cruciate substituting total knee replacement.

Method: One-hundred patients were entered into a prospective, randomized clinical trial comparing standard polyethylene tibial inserts versus the high flex polyethylene tibial insert component designs of posterior cruciate substituting total knee replacement(Genesis II, Smith & Nephew, Memphis, TN). Patients were evaluated pre-operatively, at 3, 12 months and annually thereafter. Patient demographics, radiographs, and multiple outcome measures (WOMAC, SF-12 and the Knee Society Clinical Rating System) were evaluated.

Results: No patients were lost to follow-up. One patient died prior to the two year follow up. Ninety- nine patients were reviewed at an average follow-up of 2.7 years (range 2.3 – 3.1 years). There were no significant differences in any outcome measures or radiographic findings. There were no differences in KSCRS at two years (Standard − 170, High Flex −171). There were no differences in knee flexion at 2 years (Standard− 125°, High Flex − 126°).

Conclusion: In this prospective randomized clinical trial, no differences could be seen between standard polyethylene and a “Hi- Flex” polyethylene design at a minimum of 2 years follow-up. In particular, no improvement in knee flexion was observed. Long-term evaluation will be required to comment on differences in polyethylene wear and implant longevity.

Amanda Herzog Matthew Christian Niesen Elizabeth Bishop Gausden Avery L. Buchholz Herman F. Stampfli Matthew G. Wisniewski Christine DuFour David R. Verbunker Alejandro Munoz-del-Rio Lee Kaplan

Purpose: Osteoarthritis (OA) is the most common form of arthritis in the United States and according to the National Institutes of Health, affects over 21 million people. This degenerative joint disease has repeatedly been linked to obesity. It is hypothesized that obesity, defined as a body mass index (BMI) over 30 kg/m2, increases the incidence of OA through increased joint pressure and disruption of normal metabolism. The actual changes in metabolism resulting from obesity and possibly preceding OA have not been thoroughly investigated. The purpose of this study was to identify the relationship between chondrocyte metabolism and BMI in osteoarthritic tissue.

Method: Grade 0 or 1 cartilage was removed from the medial and/or lateral femoral condyles after total knee arthroplasty. Isolated chondrocytes were then resus-pended in alginate beads at 2×106 cells/mL. The beads were equilibrated in media containing 10% fetal bovine serum for 7 days (37°C) and then separated into wells (8 beads/well) with 1 mL media. Media was replaced every 48 hours. At day 5, 9, and 13 days, glycosamino-glycan (GAG) content was measured in the cell pellet, alginate, and saved media using the dimethylmethylene blue (DMMB) assay. The DMMB results were normalized to DNA content. All procedures were approved by the University of Wisconsin – Madison, Institutional Review Board.

Results: At day 5, the average normalized GAGs from the obese group (BMI > 30 kg/m2) was > 4-fold higher than the average normalized GAGs in the non-obese group (BMI < 30 kg/m2). The 4-fold difference in normalized GAGs continued at day 9 with significance (p=0.0087) and widened at day 13, without significance. Some osteoarthritic knees had less tissue quality, therefore GAG testing was limited to earlier study days resulting in variable sample numbers for each study day.

Conclusion: The study results reveal a significant relationship between normalized GAGs and BMI in this population of osteoarthritic patients, supporting the connection between osteoarthritis and obesity previously reported. Higher patient BMI (> 30 kg/m2) may be similar to dynamic compression injuries that cause increased GAG synthesis in response to cartilage damage. In conclusion, elevated normalized GAGs in obese patients’ chondrocytes suggests increased cartilage damage.

Janie L. Astephen Michael J. Dunbar David Wilson Kevin J. Deluzio

Purpose: To investigate the association between pre-operative gait patterns and the RSA defined migration migration pattern of cemented and uncemented tibial components post total knee arthroplasty (TKA).

Method: 43 patients with primary osteoarthritis of the knee underwent Optotrack gait analysis in the week before TKA surgery. Three-dimensional net external knee joint moments and angles were calculated with inverse dynamics. The variability in subject gait patterns was captured with a set of discrete scores that represented weightings on objectively-extracted features of the gait waveform data using principal component analysis. The subjects were randomized to receive the uncemented Nexgen Trabecular metal Monoblock tibial component (n=22; mean age=66 years; mean BMI=32) or the modular cemented cobalt chrome tibial component (n=21; mean age=65 years; mean BMI=33). Both groups were posterior-stabilized and used the same design femoral component. Four experienced surgeons followed a standardized surgical technique and postoperative protocol. Within 4 days of surgery and at 6 months post-operatively, patients had bi-planar knee x-rays taken. RSA analysis was performed with MB-RSA (MEDIS, Leiden). RSA results were reported as maximum total point motion, translations and rotations at 6 months. Spearman’s rank correlations were used to examine the relationship between the first three principle component (PC) scores for each gait variable and the RSA metrics (P< 0.05).

Results: There was a highly significant correlation between MTPM and the first principal component (PC) of the knee adduction moment, which represented the overall magnitude of moment during the stance phase of the gait cycle (r=0.459, P=0.005). Higher preoperative knee adduction moment magnitudes were associated with greater MTPM postoperatively. Internal rotation of the components was correlated with the second PC of internal/external rotation moment at the knee, which represented the magnitude of the moment at load acceptance (r=0.341, P=0.042). Greater knee internal rotation moments at load acceptance preoperatively were associated with higher internal rotation postoperatively.

Conclusion: The amount of postoperative migration of the tibial component in TKA was found to be correlated with preoperative gait patterns, particularly to the magnitude of the knee adduction moment.. These results suggest that surgical success and prosthesis survivorship may be dependent on the preoperative mechanical environment of the knee joint (i.e., gait).

Mary I. O’Connor Mark P. Brodersen Laura Bancroft Julia Crook

Purpose: To determine if use of CAS in TKA improves postoperative mechanical axis alignment and component position as compared to use of standard surgical instrumentation.

Method: 200 patients were prospectively randomized to TKA utilizing CAS navigation vs. standard surgical technique. Two surgeons performed all procedures utilizing a subvastus approach, the BrainLab navigation system and posterior cruciate substituting implants. Postoperative mechanical axis alignment was measured on full length standing radiographs and component placement on CT (Perth protocol). Two independent raters measured radiographic angles. The variation in mechanical axis measures were compared between the two treatment groups using a two-sided permutation test.

Results: Surgery has been completed on all 200 patients with patient demographics similar among the two treatment groups. Median tourniquet time was increased in the navigation group (82 mins versus 57 mins, p < 0.001). Radiographic analysis of the first 100 patients showed the standard deviation of the post-operative mechanical axis measurements to be 22% lower in the navigation group than the standard surgical instrumentation group (2.4 vs. 3.0), marginally significant (p = 0.055). Optimal mechanical axis alignment (to within 3 degrees or less) was achieved in 75% of patients with navigation and in 68% of patients with standard surgical instrumentation. Analysis of all 200 pts will be completed shortly as well as results of component placement based on postoperative CT.

Conclusion: Based on analysis of the first 100 patients, use of CAS in TKA marginally statistically improved mechanical axis alignment precision compared to standard surgical technique.

Michael Tanzer Dennis Bobyn Jacintha Roberts Jan Krygier Dorota Karabasz

Purpose: The bisphosphonate Zoledronic acid (ZA) is effective for increasing net bone formation within and around implants when directly eluted from implants. The extent to which this occurs or whether ZA is more widely distributed through diffusion into the circulation is unknown. The purpose of this study was to utilize 14C-labeled ZA to quantify the localization and skeletal distribution of ZA in a canine intramedullary implant model.

Method: A solution of 100μg 14C-labeled ZA was evenly distributed onto each implant surface of three hydroxyapatite coated porous tantalum (Trabecular Metal, Zimmer Inc) implants measuring 5 mm in diameter and 50 mm in length. The implants were inserted within the left femoral intramedullary canal of an adult mongrel dog and left in situ for 6 weeks. The 3 femora with implants and all the other long bones were harvested, dried, pulverized into a fine powder and disolved in HCl. This solution was then placed in a scintillation cocktail (Ultima Gold AB, Perkin Elmer USA) and analyzed with a Packard Tri-Carb 2100TR liquid scintillator spectrometer. Data were analyzed with student’s t tests and nested analyses of variance with p=0.05.

Results: Very high amounts of ZA were present within the bone samples immediately adjacent to the implants – range 243 – 1487 ng ZA/g of bone, mean of 800 ng ZA/g. By 1 cm proximal or distal to the implant, the values diminished by up to an order of magnitude. All other bone samples contained very low amounts of 14C, (range, 0.8 – 22.6 ng ZA/g; mean 6.5 ng ZA/g), indicating diffusion of ZA into the circulation and a level of systemic distribution. This is about 11-fold less in magnitude (p< 0.0001).

Conclusion: Local elution of ZA directly from an implant results in half of the ZA being distributed locally in the femur with the rest being distributed throughout the skeleton, at levels that are much less than the therapeutic dose required to appreciably affect bone remodeling or cause complications. postoperative time periods.

James R. Brownhill Brendon J. Beaton Louis M. Ferreira James A. Johnson Graham J. W. King

Purpose: Aseptic loosening is one of the leading causes of failure in total elbow arthroplasty. It is logical to postulate that incorrect implant positioning and alignment may lead to excessive loading and wear which can induce the loosening cascade. However, the effect of implant malalignment on wear inducing loads in the elbow is not yet known. This in-vitro study determined the effect of anterior malpositioning, and varus-valgus (VV) and internal-external (IE) malrotations on humeral stem loading in total elbow arthroplasty.

Method: The humeral, ulnar, and radial components of a linked total elbow arthroplasty were optimally positioned using computer navigation in eight cadaveric elbows, mounted in a load/motion control elbow simulator (age 75yrs, range 42–93; 5 male). A modular, humeral component was employed to generate implant malpositioning errors of ±6° VV, ±8° IE, and 5mm anterior. The implant was instrumented with strain gauges to quantify VV and IE bending loads during elbow flexion with the forearm in supination. Load output was combined using a sum-of-squares technique. Passive flexion was performed with the arm in the varus and valgus orientations; passive and active flexion were performed with the arm in the vertical orientation.

Results: With the arm (humerus) in the vertical orientation, bending loads increased between 418Nmm and 1618Nmm for all malaligned implant positions (p< 0.05). Passive flexion (1354±859Nmm) produced higher resultant loads for the optimally positioned implant than active (819±891Nmm) flexion (p< 0.05). Although it varied during flexion, loading with the arm in varus (2928±1273Nmm) or valgus (2494±743Nmm) orientations resulted in up to a three-fold increase in loading when compared to the vertical orientation (p< 0.01).

Conclusion: These data demonstrate that humeral component malpositioning increases loading in the implant, however further studies are required to determine the long term effect on polyethylene wear and component loosening. Prosthesis designs that replicate the native flexion-extension axis and make use of sophisticated instrumentation or computer assistance to achieve precise positioning during implantation should lead to improved arthroplasty durability. Also, loading was higher with the arm in varus or valgus orientations, suggesting that patients should avoid activities post-operatively that require their elbow to be positioned in this way.

James R. Brownhill J. Whitcomb Pollock Louis Miguel Ferreira James A. Johnson Graham J. W. King

Purpose: Ligaments and osseous constraints are the only static stabilizers in a healthy elbow. Following arthroplasty, the use of semi-constrained, or linked, implants provides a potential third static stabilizer. However, this constraint may increase loading on the prosthesis, and hence accelerate polyethylene wear. The presence of competent collateral ligaments and the radial head would be expected to improve elbow stability and decrease loading on the ulnohumeral articulation. This in vitro study determined the effects of the collateral ligaments, radial head, and implant linkage on kinematics and wear-inducing loads in total elbow arthroplasty.

Method: Eight cadaveric upper extremities (age 73.5yrs; 5 male), were tested using an elbow motion simulator. Humeral, ulnar, and radial components of an elbow arthroplasty were positioned using a computer-assisted technique. Varus-valgus and internal-external bending loads were measured during flexion using an instrumented humeral component. A tracking receiver attached to the ulna recorded its position during active and passive flexion in the vertical orientation, and passive flexion in the varus and valgus orientations. Kinematics and loading were measured with and without implant linkage, with an intact, resected and replaced radial head, and before and after sectioning of the collateral ligaments.

Results: There were no differences in the bending loads with the arm in the vertical orientation regardless of the status of the ligaments, radial head or implant linkage (p> 0.2). Radial head excision produced an increase in valgus angulation of the ulna (6.7±6.4°) but did not influence bending loads in the vertical orientation (p< 0.05). Loading was lowest with the unlinked implant, and with ligaments and radial head intact, with the arm in the valgus (1065±466Nmm) (p< 0.01) and varus (1333±698Nmm) (p< 0.05) orientations.

Conclusion: Our results show that the radial head is an important valgus stabilizer for the prosthesis employed in this investigation. Linkage of the articulation increases implant loading during passive flexion with the arm in the varus and valgus orientations, which may increase implant wear. This suggests that, when using prostheses of this design, linkage of the articulation may be unnecessary if adequate bone stock and ligaments are available, whilst preserving or repairing the collateral ligaments and preserving or replacing the radial head.

Colin P. McDonald Graham J. W. King Terry M. Peters James A. Johnson

Purpose: The successful placement of elbow prostheses, external fixators and ligament reconstructions is dependent on the accurate identification of the elbow’s flexion-extension (FE) axis. In the case of periarticular bone loss, the FE axis must be visually estimated, as the necessary anatomical landmarks may not be available. Hence, referencing the uninjured elbow anatomy may prove beneficial in accurately defining this axis. However, this is contingent on the morphological features being similar between the two sides. Our objective was to compare distal humeral morphology between paired specimens. Our hypothesis was that anthropometric measurements from the distal humerus would be similar to the contralateral side.

Method: CT Images of 25 paired distal humeri were obtained. A right-to-left surface registration was then performed on each pair using the iterative closest point (icp) least-squares algorithm, thus placing each specimen in the same coordinate system.. Anthropometric characteristics measured (and compared between the left and right sides) included the angles of the FE and epicondylar axes in both the coronal and transverse planes, the anterior offset of the FE axis with respect to the humeral shaft axis, the length of the FE axis and the radius of curvature of the capitellum and trochlea.

Results: There was no statistically significant difference between the left and right humeri for the eight anthropometric characteristics studied (p > 0.05). The mean difference in magnitude for the FE axis angle was approximately 1.0° in both the coronal and transverse planes and the difference in magnitude for 80% of the paired specimens was less than 1.5°.

Conclusion: The anthropometric features of the distal humerus that are typically employed during elbow surgery are similar from side to side. Preoperative imaging of the contralateral normal elbow should be considered in patients with periarticular bone loss where referencing anatomical landmarks of the injured side is not possible. This information can be used as part of a preoperative plan to determine the ideal position of the implant, ligament reconstruction or external fixator during surgery. Contralateral imaging should be particularly useful when combined with computer-assisted elbow surgery.

Michael Tanzer Dorota Karabasz Jacintha Roberts Jan Krygier Dennis Bobyn

Purpose: Previous studies have shown the utility of the bisphosphonate zoledronic acid (ZA) by systemic administration and local delivery for enhancing local bone formation with porous implants. The purpose of this study was to quantify the long term effect of local delivery of ZA on bone growth within and around porous tantalum implants one year after surgery.

Method: Hydroxyapatite coated porous tantalum (Trabecular Metal, Zimmer Inc) implants measuring 9 mm in diameter and 90 mm in length were used in a canine bilateral femoral intramedullary model. Commercially pure ZA (Novartis Pharma) of either 0.05 mg or 0.20 mg ZA was applied to implants. Bilateral surgery was performed on 10 dogs – all 10 with a control implant on one side and 5 each with either a 0.05 mg or 0.20 mg ZA-dosed implant on the contralateral side. After one year, the femora were harvested and processed for undecalcified thin section histology and backscattered scanning electron microscopy. Statistical analysis was done using the student’s t tests and multiple two-level hierarchical models.

Results: The 160 histologic sections revealed that compared with controls, there was more intramedullary bone around implants dosed with both 0.05 mg ZA (+91%, p< 0.001) and 0.20 mg ZA (+115%, p< 0.001). Bone ingrowth was present in all sections and was more abundant within 1.5mm of the implant periphery. The 0.20 mg ZA dose resulted in more net intramedullary bone formation than the 0.05 mg dose (+41%, p< 0.006). The mean extent of bone ingrowth for implants dosed with 0.20 mg ZA was significantly greater than controls (+32%, p< 0.003) and also greater than for implants dosed with 0.05 mg ZA (+47% for the area within 1.5 mm of the periphery, p< 0.002).

Conclusion: This study demonstrated that the enhanced net bone formation that occurs due to local elution of ZA from porous implants was sustained out to 1 year after surgery. A notable dose response was also demonstrated. The peri-implant response was confined to within a few millimeters of the implant suggesting that ZA elution remains localized. This study supports the concept of using ZA-dosed implants for enhancing net bone formation within and around noncemented implants.

Martin J. Petrak Erica Rex Tom Turgeon Colin Badger Eric Bohm

Purpose: Implant retrieval analysis provides valuable information to researchers, clinicians and manufactures about the in vivo wear characteristics. Wear analysis can quantify visible damage on retrieved UHMWPE bearing surfaces used in total knee arthroplasty (TKA). Various researchers have developed wear scores to help provide insight into the modes of prosthetic failure. Four scoring methods are compared in order to determine their inter-rater reliability.

Method: A cohort of 60 retrieved G2, Smith & Nephew/Richards, TKA implants were analyzed by two observers using four scoring techniques. The scoring methods used had been developed by Hood, Wasielewski, Currier, and Brandt. The intraclass correlation coefficient (ICC) was used in assessing the inter-rater reliability.

Results: The ICC demonstrated significant correlation between raters (P< 0.05). Hood’s method produced a correlation of 0.89, Wasielewski’s method 0.83, Currier’s method 0.58, and Brandt’s method 0.82. All but Currier’s method had excellent correlation between raters.

Conclusion: The analysis techniques for articular surface wear for total knee bearings by Hood, Brandt, and Wasielewski showed excellent inter rater reliability; however currier’s method was only fair. One common issue among all these methods is that the scoring systems do not identify or assign differentiating weights to clinically relevant wear modalities to capture inferior implants designs. A new wear analysis technique that is efficient and assigns clinical severity weights to wear modes in TKA bearings should be investigated.

Mitchell J. Winemaker Kirsteen R. Burton Karen Finlay Danielle Petruccelli Justin de Beer

Purpose: To determine whether body mass index (BMI) is associated with mis-seating of ceramic acetabular components, and whether any associations are independent of differences in case mix.

Method: All primary total hip arthroplasty (THA) cases using ceramic components, identified from a prospective database of total joint arthroplasties performed at one center among six surgeons between 1998–2006 were radiographically reviewed. The risk of mis-seating by BMI was calculated using logistic regression models.

Results: Of the 411 THAs, 77 (20.3%) were performed in patients with BMIs that were defined as underweight to normal BMI (29.9 BMI). THA mis-seating occurred in 80 cases (19.5%). Intra-operative characteristics differed significantly according to THA mis-seating status. Univariate analysis revealed that THA mis-seating was more likely to occur in procedures performed by certain surgeons (2 trend, p = 0.01) and procedures performed in more recent years (2 trend, p = 0.02). In comparison with patients who did not incur a mis-seated THA, those patients who did incur a mis-seated THA did not have a significantly different trend in BMI (c2 trend, p = 0.09). However, adjustment for case mix, THA type, surgeon and year of procedure revealed a significant association between BMI and risk of THA mis-seating. Those patients who were overweight at the time of THA (BMI of 25.0–29.9) were at increased risk of THA mis-seating (adjusted odds ratio (OR) 2.52, 95% confidence interval (CI) 1.24–5.12, p = 0.01).

Conclusion: THA mis-seating of ceramic acetabular systems was a frequent occurrence. Although incidence of mis-seated THAs did not differ significantly by patient sex, hip side, indication, or THA component type, mis-seating did differ significantly by surgeon and year of replacement. Furthermore, patients who were overweight were more than two times more likely to suffer THA mis-seating than those who were underweight, of normal weight or obese.

Cathy Tkaczyk Alain Petit Irina Semova Fackson Mwale David J. Zukor John Antoniou Maryam Tabrizian Olga L. Huk

Purpose: Several studies have shown elevated levels of metal ions in the blood of patients with metal-on-metal (MM) total hip arthroplasty (THA). Even though there is no conclusive evidence that the elevated levels of ions have any detrimental effects on the patients, the presence of these ions is still a cause of concerns. The potential of metal ions released from MM implants for oxidative stress is unknown. In the present study, we measured the concentrations of oxidative stress markers in the plasma of patients with MM THAs.

Method: Blood from patients having MM THAs was collected up to 10 years post-operatively into Sarstedt Li-Heparin tubes. Plasma was prepared by centrifugation at 500 × g for 10 min. Plasma was chosen as opposed to whole blood because it is known that the assays for oxidative stress are not recommended for blood and can lead to erroneous data. Total antioxidant levels were measured by the Oxford Biomedical total antioxidant power assay to obtain an overview of the defense capacity of patients against oxidative stress. The activity of catalase and glutathione peroxidase, two antioxidant enzymes acting on specific reactive oxygen species, was measured by enzymatic assays. Peroxide concentrations were measured by the Biomedica Oxy-Stat assay to quantify damage to lipids in the systemic circulation. Nitrototyrosine levels were quantified using the BIOXYTECH® Nitrotyrosine-EIA assay to measure damage to proteins. Levels in patients without prostheses were used as control.

Results: There were no statistical differences in the concentrations of total antioxidants, lipid peroxides, and nitrotyrosines throughout the period of study. The activity of catalase and glutathione peroxidase was also stable over time. Moreover, there was no correlation between the concentrations of these markers and the concentrations of both cobalt and chromium ions.

Conclusion: Metal ions have the potential to induce the production of reactive oxygen species (free radicals) and cause oxidative stress in the plasma of patients with MM THAs. The present study showed that there were no changes in the levels of oxidative stress markers or antioxidant enzymes in these patients up to 10 years post-operatively. Taken together, the data strongly suggest that metal ions may not cause a significant oxidative stress in patients with MM THAs.

Clifford W. Colwell William J. Hozack J. Wesley Mesko James A. D’Antonio Benjamin E. Bierbaum William N. Capello William L. Jaffe Kenny T. Mai

Purpose: Dislocation is one of the most common complications following total hip arthroplasty (THA), with rates reported between 1% and 3%, but as high as 6% using a posterior approach with metal on polyethylene bearing surfaces. The purpose of this study was to assess the dislocation rates in ceramic-on-ceramic THAs.

Method: Primary ceramic-on-ceramic (Stryker Orthopaedics) THAs performed at 9 institutions from October 1996 through July 2005 were included in the study (1635 hips in 1485 patients). Sixty-one percent were male. The average age was 52 years (range 15–83). Osteoarthritis was the leading reason for surgical intervention (86%). A posterior approach and 32 mm or 36 mm femoral head was used in the majority of patients (90%). Patients returned for routine clinical examination or were contacted by telephone to assess for dislocations at a minimum of one year (average three years) after surgery.

Results: Of the 1635 ceramic-on-ceramic THAs performed, there were 18 dislocations (1.1%). Of these, 15 were 32 mm femoral heads; 3 were 28 mm; none were 36 mm. The majority of dislocations occurred within 3 months after surgery (72%). Closed reduction was successful in 17 hips with one requiring a revision.

Conclusion: A low rate of dislocations in ceramic-on-ceramic THAs occurred in this study (1.1%). Compared with reported metal-on-polyethylene bearing surfaces, the ceramic-on-ceramic articulation design appears to have fewer dislocations. Other factors associated with this low dislocation rate may be decreased femoral neck diameters and/or larger average femoral head size in patients receiving the ceramic-on-ceramic design. These results will need to be compared with contemporary THA using different articular surfaces.

Martin J. Petrak Erica Rex Eric Bohm

Purpose: The accuracy and precision for shoulder radio-stereometric analysis (RSA) is not as well documented as for hip and knee replacement implants. Shoulder replacement glenoid component have a relatively high rate of aseptic loosening when compared to primary hip and knee replacement components. The purpose of this study is to validate our marker based RSA system for a shoulder phantom using computed radiography.

Method: A Sawbones humerus was surgically prepared with a total shoulder implant by an experienced orthopaedic surgeon. A pegged glenoid component (3 pegs) previously marked with 7 tantalum beads was cemented into a Sawbones scapula. The glenoid component was mounted to a 32mm thick acrylic plate. The simulated humerus with implant was fixed to a linear translation stage. The stage was able to move in 0.010 mm increments with an accuracy of 0.002 mm. The Humeral component was then incrementally moved along the x, y, and z axis from 0 to 0.050, 0.100, 0.150, 0.200, 1.000 mm with duplicates taken at each increment. This examination was performed a total of 3 times. From these 9 RSA exams, the accuracy and precision of the UmRSA Digital Measure V6.0 RSA system was determined from 90 pairs of linear displacements.

Results: The standard deviation of the total average error for the X, Y, Z axis were 0.023, 0.022, and 0.070 mm respectively. The accuracy for phantom shoulder model using computer radiography was 0.008 mm in the medial direction, 0.007 mm in the superior direction and 0.019 mm in the anterior direction. The corresponding precision measurements were 0.005, 0.005, 0.015 mm.

Conclusion: This preliminary assessment of accuracy and precision of a shoulder phantom model illustrates that marker based RSA is a useful system to monitor the micro-motion of total shoulder designs.

Mohit Bhandari Sheila Sprague Sonia Dosanjh Valerie D’Aurora Heather Shearer Ole Brink David Mathews

Purpose: Domestic violence is the most common cause of nonfatal injury to women in North America and musculoskeletal injuries were the second most common manifestation of intimate partner violence (IPV). We aimed to identify the perceptions, attitudes, and knowledge about IPV among orthopaedic surgeons.

Method: Using a systematic random sample, we mailed surveys to 362 members of the Canadian Orthopaedic Association to identify attitudes towards IPV. The questionnaire consisted of three sections:

General Attitude of Orthopaedic Surgeon Towards IPV,

Attitude of Orthopaedic Surgeon Towards Victims and Batterers and

Clinical Relevance of IPV in Orthopaedic Surgery.

Up to 3 follow up mailings were performed to enhance response rates.

Results: Respondents (N = 186, response rate: 51%) consisted of 167 (91%) male orthopaedic surgeons, all actively practicing at the time of the survey. Most orthopaedic surgeons (95%) estimated that victims of IPV comprised less than 10% of their patients, the majority of whom (80%) believed it was exceedingly rare.

Conclusion: Orthopaedic surgeons grossly underestimated the prevalence of IPV in their communities. Discomfort with the issue and lack of knowledge led to misconceptions about IPV. The relevance of IPV to surgical practice was well supported but prevalence studies are needed change the current paradigm in orthopaedics.

John J. Callaghan Somyot Piyaworakhun Steve Liu Devon Goetz Richard Johnston

Purpose: To our knowledge, there are no 35 year follow-up studies of the Charnley total hip arthroplasty in the United States. The purpose of the study was to evaluate the results of a single surgeon series of primary Charnley total hip arthroplasties performed with cement at a minimum 35 year follow-up interval.

Method: Between July 1970 and April 1972, the senior author performed 330 Charnley total hip replacements with cement using a hand-packing cement technique. At minimum 35 years post-operatively, 13 patients (16 hips) were alive, with 1 patient (1 hip) lost to follow-up. Living patients were evaluated clinically with a standard terminology questionnaire, and WOMAC. Radiographic evaluation included loosening, lysis, and need for reoperation.

Results: After a minimum 35 year follow-up, only 25 (8%) acetabular components and 10 (3%) femoral components revised for aseptic loosening. For the 16 hips in living patients, 7 acetabular components (44%) and 2 femoral component (12%) were revised for aseptic loosening. Overall, 87% of the original prosthesis remains intact at the time of final follow-up, or at the time of the patient’s death. The average linear wear rate for all patients with minimum 10 year radiographic follow-up was 0.09 mm/year.

Conclusion: Our follow-up study at a minimum 35 years following Charnley total hip arthroplasty with cement demonstrates the remarkable durability of the procedure. As demonstrated in this study, the long term challenge has been revisions associated with bearing surface wear. This study should provide a benchmark for comparison to follow-up studies of other procedures and devices as they reach this interval of follow-up.

John J. Callaghan David Hennessy Steve Liu

Purpose: The original AML prosthesis was fully coated and later the manufacturer switched it to 5/8ths coating. The second generation Prodigy femoral component was developed to return to full coating of the prosthesis and to provide a medial relief to decrease bone stress shielding. The purpose of this study was to evaluate the minimum ten year results using this device and to compare the results to the same surgeon’s results at 10 years using a first generation proximally coated device.

Method: 100 consecutive primary total hip replacements were performed by a single surgeon in 86 patients using the Prodigy (DePuy, Warsaw, Indiana) femoral component between 1994 and 1997. The components were mated with 80 HGI and 20 Duraloc acetabular components. Patients were evaluated with WOMAC ratings, need for revision and radiographic loosening. The same parameters had been evaluated at minimum 10-year follow-up for the same surgeon’s initial 100 consecutive PCA (Stryker, New Jersey) primary THR’s and were compared to the present series.

Results: At minimum 10 year follow-up, 71 patients with 83 hips were living. The average clinical follow-up for the living patients was 11 years (range 10 to 12 years) and the average radiographic follow-up was 9.2 years for this group (range 7–12 years). No femoral component was revised for loosening and all femoral components were bone ingrown on radiographs. 7 acetabular components required a liner exchange or revision for polyethylene wear. This compares favorably to the same surgeon’s 10 year results with the PCA where 6 femoral components were revised for wear or loosening and an additional 2 were radiographically loose.

Conclusion: The Prodigy femoral component demonstrated excellent durability at 10 years. With the newer cementless stems with a wide variety of sizes, femoral loosening is rarely a clinical problem.

Steven J. MacDonald Kory Charron Robert B. Bourne Richard W. McCalden Douglas D. Naudie Cecil H. Rorabeck

Purpose: The increasing trend of morbidly obese patients (BMI 40+) requiring joint replacement is becoming a growing concern in Total Hip Replacement (THR) surgery. The purpose of this study was to investigate the influence that BMI may have on implant longevity and clinical outcome using prospectively collected patient data.

Method: A consecutive cohort of 2864 THR’s in 2488 patients with osteoarthritis and a minimum 2 years follow-up were evaluated. Patients were divided into appropriate BMI categories; Normal and Underweight (BMI< 25, n=650), Overweight (BMI 25–29.9, n=1069), Obese (BMI 30–39.9, n=981), and Morbidly Obese (BMI 40+, n=164). Pre-operative, latest, and change in clinical outcome scores (HSS, SF12, WOMAC) were analyzed using ANOVA and Kaplan-Meier (K-M) survivorship was determined. Categorical variables such as gender and survival status were analyzed using chi-squared.

Results: Morbidly Obese patients requiring THR’s were significantly younger than all other BMI groups by 5.4±0.83 years (p< 0.0001). Gender was also significant to BMI grouping with more females being Morbidly Obese and Normal or Underweight (p< 0.0001). All pre-operative and latest HHS and WOMAC domain scores were lower for the Morbidly Obese, significantly in all preoperative score domains and latest HHS Function (p< 0.05). The change in clinical scores from pre-operative to latest was greatest in all domains for the Morbidly Obese group. K-M cumulative survival with implant revision as the endpoint at 10 years was not different between the BMI groups. Revision rates for infection for the Morbidly Obese, Obese, Overweight, and Normal were 1.3%, 0.65%, 0.3% and 0.69% respectively. Overall Revision rates for the Morbidly Obese, Obese, Overweight, and Normal were 6.7%, 5.4%, 6.9% and 5.7% respectively and were not found to be significant (p=0.496).

Conclusion: The Morbidly Obese cohort undergoing THR had significantly lower preoperative and lower postoperative clinical outcome scores than all other BMI groups but demonstrated the most significant improvement. No difference was found in the K-M survivorship although revisions and revisions for infection were not equal between the groups

Kit R. F. S. Brogan John P. Charity Ashan Sheeraz Mathew J. Hubble Jonathan R. Howell

Purpose: There is evidence that recommends the retention of a well-fixed cement mantle at the time of revision hip arthroplasty. The cement-cement interface has been proven to have a greater shear strength than a new bone-cement interface after removing the old cement mantle.

Method: This study reviewed a series of acetabular revision procedures with a minimum 2-year follow-up where the original cement mantle was left intact. From 1988 to 2004, 63 consecutive cement-in-cement revisions of the acetabular component were performed at our institution. Outcome was based on functional assessment using the Oxford, Charnley, and Harris scoring systems as well as radiographic analysis using the DeLee and Charnley criteria.

Results: In total 63 procedures were performed in 61 patients (40 female and 21 male), whose mean age at surgery was 74 years (range 40 to 99 years). 47 hips (75%) were performed for recurrent dislocation, 13 for aseptic loosening, 1 for pain, 1 for excessive shortening, and 1 for disarticulation of a constrained liner. No case was lost to follow-up. There was a significant improvement in the functional scores from the pre-operative status with the patients maintaining a low level of pain. There was one re-revision for aseptic cup loosening at 7 years, with 1 further case of radiological loosening identified at the latest review. There were 6 further cases of dislocation 5 of which were treated with further in-cement revisions. All other cases showed well-fixed components on radiographic analysis and no evidence of failure at the most recent follow up.

Conclusion: The cement-in-cement revision technique can be used in selected cases of acetabular revision surgery, providing satisfactory functional outcomes backed up by good radiographic results. Blood loss and surgical time are also significantly decreased.

Rena Lorraine Stewart James Stannard David Volgas Justin Duke Irshad Chaudry

Purpose: Autologous bone grafting is considered the gold standard for multiple orthopaedic indications, including non-union of fractures and other bone defects. Previously autograft was most commonly harvested from the iliac crest, with an estimated complication rate of greater than 10%. New technology, the RIA system, allows harvest of graft material from the medullary canal of the femur. The purpose of this study is to examine the osteo-inductive properties of this human femoral bone graft obtained using the RIA system and the RIA filtrate combined with chronOS (Tricalcium Phosphate). This study will examine whether these materials will induce bone growth when implanted in a rat sub-muscular pouch model.

Method: Three samples were collected from each human subject. These included:

femoral bone graft obtained using the RIA {n=10}

chronOS washed with RIA filtrate {n=10}and

a mixture of these two materials {n=10}.

chronOS (alone) was used as control {n=10}. These materials were implanted into a sub-muscular pouch in athymic rats (to eliminate rejection of the xenograft). Rat serum levels of BMP-2, VEG-F, TGF-β and IL-10 were obtained at days 7, 14, 21 and 28. Rats were sacrificed at day 28 and radiographic and histologic examinations and histomorphometric analyses were performed.

Results: Overall, there were no significant differences in BMP-2, VEG-F, TGF-β and IL-10 levels either between groups or between time points. Average serum values for BMP-2 decreased over time for all groups. Histologically and radiographically, all four materials induced new bone production. chronOS alone produced the greatest volume of new bone while RIA reamings alone produced the least. Histological analysis demonstrated formation of normal bone.

Conclusion: The RIA system allowed for harvest of femoral bone graft. This graft induced bone formation and increased osteogenic protein levels when implanted in the rat model. The RIA filtrate, when combined with Tricalcium Phosphate, is equally osteoinductive. Combining reamings with filtrate material may allow large volumes of graft to be produced using this system. This new technology may allow the collection of large volume, osteoinductive grafts without the complications previously described for iliac crest bone graft harvesting.

Rena Lorraine Stewart Tien-Min Chu James Stannard David Volgas Justin Duke

Purpose: One of the most difficult challenges for orthopaedic surgeons is the management of bone loss resulting in a segmental bone defect. Segmental bone defects are ubiquitously difficult to treat, require multi-phase surgery and have frequent complications. A promising new strategy involves combining tissue engineering techniques with the delivery of biologically active proteins to facilitate bone regeneration. The purpose of this study is twofold:

First, to investigate whether a cylindrical, biodegradable load-bearing scaffold, stabilized with an intramedullary (IM) nail, will facilitate early weight bearing in a critical sized canine defect model.

The second objective is to investigate if rhBMP-2, transported by the biodegradable carrier, will enhance bone formation and healing across a critical sized canine defect.

Method: A critical size defect of 3 cm was created in the canine tibia by osteotomy. A cylindrical, biodegradable scaffold of (poly) propylene fumarate was inserted into the defect and the tibia was stabilized with a locked intramedullary nail. Half of the scaffolds were impregnated with 300μg rhBMP-2 and half remained as controls. The animals were allowed immediate weight bearing post-operatively. X-rays were obtained post-operatively and at weeks 1, 2, 3, 6, 12, 18, and 24. X-rays were assessed for loss of height, integrity of the scaffold, and presence of bridging callous formation.

Results: The animals that received scaffolds treated with rhBMP-2 showed abundant callus formation on X-ray. Partial bridging callus formation in this group was seen at 3 weeks. Complete bridging callus (bridging on 4 cortices) was observed by 6 weeks. These specimens maintained height of the defect and overall length of the tibia. Controls demonstrated minimal callus formation at all time points. By 3 weeks significant loss of defect height was observed. By 6 weeks failure of hardware (breakage of interlocking screws and/or screw loosening) was evident.

Conclusion: This study shows that biodegradable scaffolds, treated with rhBMP-2 and implanted in a critical sized defect facilitate bridging callus formation and healing across the defect. This data indicates that biodegradable scaffolds made of (poly) propylene fumarate are suitable carriers for rhBMP-2 while providing initial structural support for weight bearing.

Earl R. Bogoch Victoria Elliot-Gibson Rob Wang Robert Josse

Purpose: We report the prevalence of vitamin D deficiency and other causes of secondary osteoporosis in a group of typical and atypical fragility fracture patients.

Method: A chart audit of 399 patients (117 males, mean age 64.6, SD 12.8; 282 females, mean age 63.5, SD 14.6) referred from an inner city orthopaedic unit to the Metabolic Bone Disease Clinic (MBDC) over a three-year period was conducted. Fracture locations and etiology: 90 hip (76 fragility), 161 wrist (135 fragility), 8 vertebral (6 fragility), 77 shoulder (62 fragility), 62 other sites (45 fragility), 1 both hip and shoulder (fragility).

Results: Thirty percent of patients (42 males, 78 females) had a total of 149 secondary causes of OP recorded. Secondary causes included medication use (oral steroids, anti-convulsants); rheumatic, gastrointestinal and endocrine conditions (RA, IBD, Graves disease, Type I DM, hyperparathyroidism); hypogonadal states (premature ovarian failure, hypogonadism); genetic conditions (hypophosphatasia); hematological conditions (thalassemia); miscellaneous causes (smoking, renal impairment). A total of 308 patients completed blood work, including 269 patients who had a 25-OH vitamin D measurement: 7 patients were deficient at ≤ 25 nmol/l, 137 were insufficient at 26 to 74 nmol/l, and 125 were sufficient at ≥ 75nmol/l. There were no differences between males and females (p = 0.457), or among fracture locations (p 0.246). Over 75% of blood/urine analyses were within the normal range for: 1,25 vitamin D, ALP, ALT, AST, bilirubin, creatinine, T3, T4, homocysteine, magnesium, phosphorus, platelets, serum calcium, protein, albumin, globulin, TSH, tissue transglutaminase, Vit B12, WBC, 24 hour urine calcium and phosphorus. Between 50 and 74% of the blood/urine analyses were within the normal range for: CRP (n = 30; 30% elevated), ESR (n = 173; 43% elevated), testosterone (n = 53; 25% of men below normal), bioavailable testosterone (n = 52; 40% of men below normal), N- telopeptide (n = 5; 30% of women elevated), RBC folate (n = 12; 33% elevated), 24 hour urine creatinine (n = 51; 27% below normal).

Conclusion: Half of the fracture patients were vitamin D insufficient. A standardized blood test protocol for all fragility fracture patients is in use.

Ru Li Herbert P. vonSchroeder Duncan J. Stewart Emil H. Schemitsch

Purpose: Micro-CT is efficient, non-destructive, and accurate for qualitative and quantitative studies of bone microarchitecture during fracture healing. A cell-based vascular endothelial growth factor (VEGF) gene delivery system can increase fracture healing. Three dimensional structural variation of new bone formation in rabbit fracture segmental defects was studied with micro-CT to determine how VEGF affects these microarchitectural differences for bone healing in various periods.

Method: All animal procedures were approved by the Animal Care Committee at St. Michael’s hospital. Ten millimeter segmental bone defects were treated by local injection with cell-based VEGF gene transfer (n=15), or control group with fibroblasts alone or saline only (n=15), to stimulate differences in bone healing. The animals were sacrificed and fracture healing specimens collected at 4, 8 and 12 weeks post surgery. The region of interest (ROI) was set where the segmental defect was located, and was selected for analysis from the recognizable margins of the original defect. To describe the topographic pattern of bone healing, the ROI was divided into three areas of equal volume: proximal, middle and distal. The new bone formation and mineralization at the defect sites were evaluated by bone structural parameters from the 3-D reconstruction of micro-CT.

Results: Macroscopic evaluation of the interfragmentary section from reconstructed micro CT scans, in the VEGF treated rabbits, showed abundant fragmentary bone filling the gap of the osteotomy at 4 weeks and abundant callus bridging the gap at 8 and 12 weeks. In the control group, only small amounts of sparsely formed bone were seen in the gap at 4 weeks. In the control group, the regenerate bone was ovoid around the bone sites and a big gap remained in the segmental bone defects at 8 and 12 weeks. The bone healing micro-structural differences between the two groups varied with the period of treatment, with more differences seen at 4 than 8 or 12 weeks.

Conclusion: Cell-based VEGF gene therapy enhances fracture healing of segmental defects, and this effect is best seen in the early period following defect creation.

Craig S. Mauro Alex J. Kline Susan S. Jordan James J. Irrgang Freddie H. Fu Brian A. Williams Christopher A. Radkowski Christopher Harner

Purpose: While several studies have reported improved pain control with use of femoral nerve blocks (FNB) following ACL reconstruction, there are few studies that have evaluated the effect of continuous perineural infusion on quadriceps activation and recovery of range of motion after ACL reconstruction. The purpose of this prospective randomized placebo-controlled clinical trial was to determine if the use of continuous infusion of levobupivacaine for pain control following ACL reconstruction had an adverse effect on postoperative quadriceps activation and recovery of ROM.

Method: Two-hundred-seventy patients underwent ACL reconstruction and were randomly assigned to one of three FNB groups (placebo bolus and infusion, active bolus with placebo infusion, or active bolus and continuous infusion). The patients’ ability to perform a SLR was assessed daily for the first four post-operative days. Range of motion of the knee was measured with a goniometer 1, 4, 8 and 12 weeks after surgery. Range of motion complications requiring arthroscopic debridement, manipulation under anesthesia, or application of a drop-out cast were recorded.

Results: There were no significant differences between groups in their ability to perform a SLR on postoperative day 1 through 4. There were also no differences between active and passive ROM values between groups at each follow-up period. There were 7 (3.2%) early ROM complications, but no detectable differences between groups.

Conclusion: Continuous perineural infusion of levobupivacaine (0.25% at 5mL/hr for 50 hours) following ACL reconstruction does not appear to negatively influence quadriceps activation as evidenced by the inability to perform a SLR or adversely affect recovery of range of motion in the early postoperative period after ACL reconstruction. Continuous perineural infusion can provide effective pain relief without adversely affecting post-operative recovery following ACL reconstruction.

Laurie A. Hiemstra Mark Heard Greg Buchko Treny M. Sasyniuk Jeremy Reed Brad Monteleone

Purpose: To determine if patients randomized to a knee immobilizer following a primary hamstring tendon anterior cruciate ligament (ACL) reconstruction have lower visual analog scale (VAS) pain scores at day two postoperative than patients who do not wear a knee immobilizer.

Method: Patients aged 18–40 with symptomatic ACL deficiency as determined by MRI or physical exam who met the study inclusion criteria were eligible. Patients meeting intra-operative inclusion critiera were randomized (immobilizer or no immobilizer) during wound closure. The immobilizer used was a soft unhinged brace with velcro straps and three metal bars (Breg). Pre, intra and post operative protocols were standardized. Analgesic use and VAS scores were recorded at: one hour after surgery, 8am and 8pm for the first two days postoperative, and 5pm for days 3–14 postoperative. Patients were examined by the surgeon within 14–28 days postoperative. Based on a published survey and the literature, the primary outcome was patient self-assessed pain using a 0–100mm VAS (no pain-worst pain) at day 2 postoperative. Secondary outcomes included: analgesic use, complications, and range of motion. A sample size estimate was calculated resulting in 44 patients per group. A total of 102 patients were enrolled; 88 randomized and 14 excluded intra-operatively. Recruitment was achieved within 11 months.

Results: There was no difference in mean VAS pain scores at 2 days post-operative between immobilized and non-immobilized patients (32.6 and 35.2, respectively; p=0.59, 95% CI −6.99, 12.3). Regardless of group allocation, the greatest pain reported was on the evening of day 1 post-operative. Throughout the first week, patients medicated to a pain level of approximately 30/100. There were no differences between groups in medication consumed, range of motion or complications. At 2 days post-operative all patients randomized to the immobilizer group reported that they worn their brace 76–100% of the time.

Conclusion: No differences in pain were detected between immobilized and non-immobilized patients at any point during 14 days post ACL reconstruction. Based on these findings, a knee immobilizer is not recommended post-operatively for pain control. This study does not address other reasons for immobilizer use such as graft protection or range of motion.

Paul A. Martineau Stephen D. Fening Jack T. Andrish Anthony Miniaci

Purpose: Tibial slope is an important contributor to sagittal plane stability. Anterior opening wedge high tibial osteotomy (HTO) has received increased attention for sagittal plane correction. A previous study demonstrated that anterior opening wedge HTO induced no increased strain in the ACL [1]. The goal of this present study was to determine the effect of increasing tibial slope on the strains of the major ligamentous restraints of the knee and on the change in position of the tibia in relation to the femur.

Method: Six cadaveric knee specimens were mounted at 15 degrees of flexion in a testing apparatus providing both compressive and anterior loading. Strains were measured in the ACL, PCL, MCL, and LCL for six randomized loading combinations and 3 conditions: intact, after anterior opening wedge HTO with 5mm plate, and 10mm plate. Tibial translation, rotation measurements and tibial slopes were obtained for each test.

Results: ACL strain was significantly associated with the plating intervention (p< 0.001). ACL strain decreased from −0.66 +/− 1.48 at baseline to −7.44 +/− 6.60 with a 5mm anterior opening wedge HTO and −7.99 +/− 6.45 with a 10mm osteotomy. Stepwise regressions yielded no significant effect of compression, anterior loading or osteotomy or combination thereof on PCL, MCL or LCL strain. Tibial slope and external rotation were significantly correlated with the plating intervention (p< 0.001 for both).

Conclusion: Increasing posterior slope via HTO did not increase strain in any of the major ligamentous restraints of the knee. Increasing tibial slope in the setting of a ligamentous deficient knee can be performed to increase stability without fear of submitting ligaments to increased strain.

Jaswant Singh Khangarot

Purpose: Fracture-dislocation of the talus is one of the most severe injuries of the ankle. Opinion varies widely as to the proper treatment of this injury. Since Blair’s original description of the tibiotalar fusion in 1943, there is little mention in the literature of his method. The present study reports tibiotalar arthrodesis with modification in Blair’s technique.

Method: Eleven cases of modified Blair’s tibiotalar arthrodesis were retrospectively studied. The average age was 32.4 years (range, 26 to 51 years). Six patients had avascular necrosis; five had neglected fracture-dislocation of the talus

Results: All the 11 ankles united. Nine cases having 150–200 tibiopedal motion had excellent results and two ankles having 100–150 of tibiopedal motion had good result. The follow up ranged from 3 to 12 years.

Conclusion: The principal modification in the present study is retention of the talar body while performing arthrodesis with anterior sliding graft. The retention of the talar body provides intraoperative stability and in long term, the retained talar body share the load transmitted to anterior and middle subtalar joints thus resulting into improved hind foot function and gait.

Gabriel Ayonmigbesimi Akra A. O. Adedapo

Purpose: To determine, the foot pressure pattern in ankle osteoarthritis before and after ankle fusion. To compare the results with those of normal individuals.

Method: The distribution of plantar pressures of the foot has been measured by different means ranging from crude methods to modern techniques using transducers in the form of mats and insole devices. A less cumbersome in-sole transducer called FSCAN sensor has become commercially available. This device has been used to measure dynamic pressures at the Shoe-Foot interface in normal people and in pathological conditions in the foot. However the pressure distribution in the soles of patients with ankle osteoarthritis has not been studied. We present a prospective case control study of 18 participants (9 with ankle osteoarthritis and 9 controls). Ethical approval was obtained for this study. The controls were matched to cases by foot shape, gender and weight. The pressure measurement device, technique of ankle fusion and post operative protocol (for the arthritis patients) were standardised for all the participants. The Ankle-Hindfoot Scale and SF-36 Health Survey scores were obtained pre-operatively and at six months post-operatively and compared.

Results: There were four females and 14 males. The average age was 67 years. The forefoot in patients with arthritis bore more weight compared to controls and this was statistically significant (P< 0.05). The forefoot pressure was also higher than the hind foot pressure in the patients, both preoperatively and post operatively. This was also statistically significant, (P< 0.05). The Ankle-Hindfoot Scale improved significantly postoperative, (P< 0.05). There was no statistically significant difference in the SF-36 Health Survey scores.

Conclusion: The study shows that ankle osteoarthritis changes the pressure distribution in the foot, with preponderance in the forefoot. It also shows that after ankle fusion there is a change in the pressure. However, the forefoot still bears more pressure compared to the hind foot. The result may help in predicting areas of the foot at risk in developing problems due to high pressure load post ankle fusion. It may also help in designing foot orthosis in the peri-operative management of the foot in ankle osteoarthritis.

Sanaz Hariri Edgar T. Savidge James Zachazewski Thomas Gill

Purpose: Patellar tendonitis (i.e. jumper’s knee) commonly affects young adult athletes who use their knee extensor mechanism in a repetitive and/or intense manner, such as in basketball and volleyball. There is a small but significant percentage of patients with persistent symptoms despite at least a six-month course of conservative management. For these patients, we perform knee arthroscopy and open patellar tendon debridement. This study presents the indications, technique, and clinical results of open patellar debridement.

Method: We investigated the clinical outcomes of 38 consecutive cases of open patellar tendon debridements (3 were bilateral) in 35 patients without previous open ipsilateral knee surgery over 7 years.

Results: Two patients (2 knees) were lost to follow-up (94% follow-up rate). The average age at surgery was 29 (SD 10, range 14–51). There were 21 males and 12 females. At an average follow-up of 43 months (SD 21, range 15–92 months), the Lysholm score showed 27 knees with good or excellent results, 4 fair, and 2 poor. The average post-operative IKDC score was 79 (SD 14, range 41–100). When compared to the pre-operative value, the post-operative Tegner Activity Scores showed no change (average change 0, SD 2, p=0.20), and Visual Analog Pain Scores decreased by an average of 6 points (SD 3, p< 0.001). Twenty-seven patients were completely or mostly satisfied with the surgical outcome, 4 were somewhat satisfied, and 2 were dissatisfied. Twenty-seven patients (82%) said that they would have the surgery performed again for the same problem.

Conclusion: Patellar tendon debridement significantly reduces knee pain in patellar tendonitis patients without significantly affecting their activity level; the great majority of patients are satisfied with the results of the procedure.

Paul Tornetta William Ricci Toney Russell Bob Jones Timothy Petteys Darin Gerlach

Purpose: Many lateral malleolar fractures in patients with osteoporotic bone are rotationally unstable, requiring fixation stable in torsion with good fatigue properties, but without bulk due to the soft tissue constraints. The purpose of this study was to evaluate the torsional performance of a thin (1.5mm) plate with locked and non-locked constructs in a simulated osteoporotic lateral malleolus fracture.

Method: A transverse fracture gap to mimic comminution was created in (15 lb/ft3) density foam. 3 bicortical unlocked screws were used proximal to the fracture in a 5 hole thin (1.5mm) plate for both constructs. Distally, two screws that did not breach the far cortex (12mm) were placed as locked in one group and unlocked in the other. The constructs were loaded in torsion at 1 Hz at 7.5/0.75 in-lbf (0.85/0.08 N-m) of torque. A torsional fatigue failure was defined as either a fracture of the plate, screw pull-out, or construct rotation 10 degrees beyond the maximum initial rotational displacement. Testing was conducted until construct failure or run-out of 300,000 cycles.

Results: The thin plate constructs with locked distal screws showed significantly improved fatigue properties (p< 0.00001). None of the locking plate constructs failed prior to the 300,000 cycle end point. In stark contradistinction, all of the non-locked contructs failed at an average cycle count of only 9,541 (range 1,000 – 23,000 cycles). The failure mode for each of the non-locked constructs was pull-out of the distal screws.

Conclusion: These results indicate that the use of a thin plate with locking capability provides a significant advantage over non-locked constructs in fatigue performance in areas of poor bone density subjected to torsional loads, such as the lateral malleolus.

André Leumann Martin Wiewiorski Olaf Magerkurth Thomas Egelhof Helmut Rasch Victor Valderrabano

Purpose: Osteochondral lesions (OCL) of the talus are a common pathology among patient who suffered a traumatic injury of the ankle joint and involve breakdown of articular cartilage and underlying bone tissue. The estimated incidence of OCL is 6% in all ankle sprains and the importance of a traumatic ankle event was confirmed by several authors by arthroscopical joint assessment. The most common locations for OCL to occur are at the posteromedial and anterolateral aspect/section, involving the mortise/edge of the dome. One of the orthopaedic world’s most current research topics is the aim to produce tissue engineered osteochondral grafts for future treatment of OCL lesions. For the exact anatomic reconstruction, the dimensions of the medial and lateral talar dome must be considered. Few data is available regarding the normal anatomic talar dimensions on standard radiographs of ankle joints. The purpose of this study was to collect data describing the normal talar dome anatomy of the ankle joint on antero-posterior hindfoot radiographs and to assess value distribution in a large patient group. Hypothetically the medial talar dome has a significant greater curvature and a greater edge angle than the lateral talar dome.

Method: 81 patients (81 ankles) (30 female, 51 male; average age 43y (range 20–87y)) without ankle and hindfoot pathologies were included. Weight-bearing standard AP ankle radiographs were performed on a digital flat panel system (Aristos FX®, Siemens Erlangen, Germany) and evaluated on a high resolution case reading monitor (Totoku) using DICOM/PACS review application E-Film.

To measure the edge angle of the medial (alpha) and lateral (beta) talar dome, curves were adjusted along the medial and lateral talar body and on top of the talar dome measuring the angles in-between.

To measure the radius, circles were fitted into the medial and lateral talar dome (rm and rl).

Results: There was a significant difference (p< 00.1) between mean medial edge angle (alpha) with 109.99 degree (range 90–127; SD 7.14) and lateral edge angle (beta) with 91.84 degree (range 79–111; SD 5.56). Also a significant difference (p< 00.1) has been demonstrated between the mean medial talar dome radius (rm) with 4.8 mm (range 2–8; SD 1.3) and lateral talar dome radius (rl) with 3.5 mm (range 1.2–8.5; SD 1.5).

Conclusion: This study shows a significant difference between medial and talar dome configuration. The assessed data provides important aid for engineering of pre-formed, pre-sized osteochondral grafts. Such pre-shaped grafts could help restoring the physiological joint surface by matching exactly into the lesion and consequently achieving the recovery of the physiological joint biomechanics and prevention of secondary degenerative disease.

Martin Wiewiorski Martin Kretzschmar Helmut Rasch Deniz Bilecen Augustinus Jacob Victor Valderrabano

Purpose: Osteoarthritis (OA) is a common disease with increasing prevalence and rising socioeconomic burden. Of all symptoms accompanying OA, pain is the most disabling and frequent and the major reason why patients affected seek medical help. The determination of the origin of chronic foot OA pain is challenging since clinical examination of the foot faces a complex anatomy with several joints, osseous, and non-osseous structures contributing to the symptoms. For OA non-invasive imaging methods like plain radiograph, CT or MRI underestimate the degree of degenerative changes and show a poor correlation with pain degree. Studies using functional imaging based on the detection of activated osteoblasts with 99mTc-Dicarboxypropandiphosphate (DPD) to indicate painful facet joints in the lower spine show promising results, but so far no evaluation for chronic OA pain conditions in foot joints has been conducted and the diagnostic potential was limited due to poor spatial resolution of the scintigraphic assessment. Single Photon Emission Computed Tomography – Computed Tomography (SPECT-CT) is a new hybrid technique combining metabolic information with an exact anatomical localization. We hypothesised that diagnostic infiltration with a local anaesthetic of a painful hindfoot or midfoot joint showing 99mTc-DPD-uptake in SPECT-CT, leads to a positive OA pain response.

Method: 26 patients with chronic OA pain and radiological signs of OA in a hindfoot or midfoot joint (27 feet) were included. Plain radiography was performed to detect degenerative changes and to rule out pathologies different from OA. Pain status was measured by Visual Analogue Scale (VAS). AOFAS hindfoot/midfoot score and SF-36-score were documented.. All patients received a 99mTc-DPD SPECT-CT (Symbia T2, Siemens). The localisation of 99mTc-DPD-uptake and consequently the site of infiltration were defined. The infiltration was performed with a local anaesthetic (bupivacaine) and iodine solution under CT-guidance with exact documentation of the contrast media deposit by CT. Pain status was assessed directly post-infiltration. Pain relief in responders was defined as reduction of VAS-score > 50% immediately after infiltration, partial response as reduction of < 50%.

Results: Infiltration was performed in 26 hindfoot joints and 5 midfoot as indicated by 99mTc-DPD-uptake in SPECT-CT. Subsequent CT control scans showing contrast media depot confirmed exact successful infiltration in all indicated joints. In 22 patients an immediate significant (p< 0.01) postinterventional pain reduction of VAS more than 50% was observed. Mean VAS before infiltration was 5.77 (range 2–10; SD 2.22) and 0.82 (range 0–4; SD 1.26) immediately after infiltration. Two patients showed a partial response and one patient showed no pain resolution after infiltration.

Conclusion: The results show a significant correlation of uptake and pain resolution after infiltration allowing precise identification of OA hindfoot joints as pain inducing foci. Non-invasive SPECT-CT offers good prediction of outcome after infiltration improving the localisation of the pain inducing pathology, thus aiding in pre-operative planning and avoiding unnecessary interventions, as diagnostic infiltrations, with its possible risks and side effects.

Vani Sabesan Mark Easley

Purpose: Currently, the modified Kidner procedure is recommended to treat the symptomatic accessory navicular that fails nonoperative management. Some foot and ankle specialists have cautioned that excision of the accessory navicular can lead to a progressive increase in pain and loss of the longitudinal arch. As a result, they have recommended ORIF of the symptomatic accessory navicular as a surgical alternative. To our knowledge, the only references to this surgical alternative in the orthopedic literature are two technique papers.

Method: Between 1999 and 2005, 17 patients were treated with symptomatic type II accessory naviculars that failed nonoperative measures. A standard treatment algorithm was followed:

accessory naviculars of adequate size underwent an ORIF (10), and

accessory naviculars of smaller size underwent a modified Kidner procedure (7).

Corrective osteotomies and/or soft-tissue procedures were performed concomitantly in nine patients to address pes planus. Pre- and postoperatively, patients were assessed radiographically. Preoperative MRI scans were analyzed to see if there was any correlation between MRI findings and success of ORIF. Patients were evaluated with the AOFAS midfoot clinical rating system (max 100 points).

Results: In the patients treated with ORIF, average follow-up was 31 months. The average AOFAS mid-foot score improved from 49 to 89 points. Radiographic analysis suggested an 80% union rate. However, only one patient out of ten (10%) undergoing ORIF with subsequent nonunion was symptomatic and her pain resolved after screw removal. In the patients treated with excision, average followup was 48 months. The average AOFAS score improved from 45 to 78 points. Three of seven feet (43%) treated with accessory navicular excision had persistent midfoot pain at last followup with clinical and radiographic signs of progressive loss of the longitudinal arch. Twelve patients had a preoperative MRI of the foot with all showing edema suggesting an injury to the synchondrosis. We found no correlation between MRI findings and success of ORIF of the accessory navicular.

Conclusion: As suggested by previous technique papers and this study, ORIF of the symptomatic type II accessory navicular may have merit. We anticipate that this study will prompt a comprehensive multicenter evaluation of this technique.

Aaron B. Ng Foley Adeyemo Richard Samarji

Purpose: Previous studies have demonstrated higher infection rates following elective procedures on the foot and ankle as compared with procedures involving other area of the body. Previous studies also have documented the difficulty of eliminating bacteria from the forefoot prior to surgery. The purpose of the present study was to ascertain that preoperative chlorhexidine bathing provide significant local flora reduction than placebo in elective foot and ankle surgery.

Method: From October 2005 to October 2006, a prospective study was undertaken to evaluate 50 consecutive patients undergoing planned, elective surgery of the foot and ankle. 50 patients were prospectively enrolled and randomly assigned to have preoperative footbath with Chlorhexidine Gluconate (Hibitane) (Group 1) or placebo (Group 2). Culture swabs were taken from all web spaces, nail folds, toe surfaces and proposed surgical incision sites before the preoperative antiseptics bath, during the procedures and immediately completion of surgery.

Results: 50 patients were enrolled (mean age: 42.6 years; range: 19–85; F: M = 29:21). 25 patients are assigned to each groups. 100% bacterial isolation preoperatively in both groups prior to antiseptics bathing. In group1, bacteria grew on intraoperative culture in 60% cases and 0% in immediate post-operative culture. In group 2, 96% in intraoperative swab culture and 16% in postoperative swab culture. The intraoperative swab culture bacterial count is statistically significant (p= 0.002). The postoperative swab culture bacterial count is marginally significant (p=0.055) when comparing 2 groups. No complications were recorded in both groups.

Conclusion: These data indicate that chlorhexidine provides better reduction in skin flora than placebo. Based of these data, we recommend the use of chlorhexidine footbath as well as the surgical preparatory agent for the foot and ankle surgery.

Gillian Hatfield Cheryl Hubley-Kozey Kevin J. Deluzio Michael J. Dunbar William D. Stanish

Purpose: The purpose of this study was to determine what differences exist in the knee flexion, rotation and adduction moments and periarticular knee muscle activation patterns between subjects with medial compartment knee osteoarthritis (OA) and those with lateral compartment knee OA.

Method: Forty eight individuals with knee OA were studied. The group was divided into those with predominantly medial compartment involvement (38 subjects, age 63 ± 8 years) and those with lateral involvement (10 subjects, age 63 ± 9 years). Three-dimensional motion (Optotrak) and ground reaction force (AMTI) data were collected while the subjects walked at a self-selected velocity. The knee flexion, rotation and adduction moments, time normalized to the percentage of one gait cycle, were calculated using an inverse dynamics approach. Electromyograms (EMG) were also collected from the rectus femoris, vastus lateralis, vastus medialis, medial and lateral hamstrings, and medial and lateral gastrocnemius and normalized to maximum voluntary isometric contractions. Knee moments and waveforms for each muscle for one complete gait cycle were analyzed for group differences using principal component analysis (PCA) followed by Student’s t-tests (alpha-adj = 0.017) for the PCA scores.

Results: The two groups were statistical similar in terms of age, height, weight, and walking velocity (p> 0.05). PCA analysis revealed statistically significant differences (p< 0.017) in patterns for the knee adduction moment, medial gastrocnemius, and lateral hamstrings between the two groups.

Conclusion: As expected, there was a difference in the knee adduction moment between the two groups. What is novel is that the muscle activation patterns from the lateral site group are consistent with an attempt to unload that compartment. The results of this study provide evidence that biomechanical and neuromuscular differences do exist, depending on the OA site. This could have implications for developing site-specific conservative management approaches

Victor Valderrabano Lukas Ebneter André Leumann Vinzenz von Tscharner Beat Hintermann

Purpose: Ankle sprains are among the most common injuries in sports and recreational activities. 10 to 40% of the acute ankle sprains lead to chronic ankle instability (CAI), which can be divided into its mechanical and its functional division. The clinical-orthopaedic diagnosis of mechanical ankle instability (MAI) has been well established, whereas the etiology of the functional ankle instability (FAI) is still not objectively allocatable. The aim of this study was to identify neuromuscular patterns in lower leg muscles to objectively describe the FAI.

Method: 15 patients suffering from unilateral CAI (mean age, 35.5 years) since 2.4 years (1–9 years) were examined. The patients were evaluated etiologically and clinically (VAS pain score, AOFAS Ankle Score, calf circumference, and SF-36). Electromyographic (EMG) measurements of surface EMG with determination of mean EMG frequency and intensity by wavelet transformation were taken synchronously with dynamic stabilometry measurements. Four lower leg muscles were detected: tibialis anterior (TA), gastrocnemius medialis (GM), soleus (SO), and peroneus longus (PL) muscle. 15 healthy subjects were tested identically.

Results: Patients showed higher stability indices, higher VAS score, and lower AOFAS Ankle Score. The mean EMG frequency was significantly lower for the PL (pathologic leg, 138.3 Hz; normal leg, 158.3 Hz, p< 0.001). Lower mean EMG intensity was found in the pathologic PL and GM. The mean EMG frequency of the TA was lower in the patient group, its intensity higher.

Conclusion: Patients suffering CAI demonstrate weakened stability and impaired life quality. Neuromuscular patterns of the GM, PL and TA lead evidently to an objective etiology of the functional ankle instability. EMG patterns of four lower leg muscles indicate chronic changes in muscle morphology, such as degradation of type-II muscle fibres or modified velocity of motor unit action potentials. Accurate prevention and rehabilitation may compensate a MAI with a sufficient functional potential of lower leg muscles. This may also avoid operative treatment of MAI. The present study evidences the etiology of the FAI with objective parameters and indicates chronic changes in muscle morphology within CAI-Patients.

Won Kim David Backstein Facundo Las Heras Oleg Safir Kenneth P. H. Pritzker Allan E. Gross

Purpose: Fresh osteochondral allograft (FOCA) transplantation has been an effective treatment option with promising long-term clinical outcomes for focal post-traumatic or intra-articular lesions in the knee for young, active individuals. The goal of this study was to assess the osteochondral allograft to characterize the histopathologic features of early and late graft failure, as well as prolonged graft survival.

Method: We examined histological features of thirtyfive fresh osteochondral allograft specimens retrieved at the time of subsequent graft revision, osteotomies or total knee arthroplasty.

Results: The graft survival time in our samples ranged from one to twenty-five years based on their time to reoperation. Histological features of early graft failures were lack of chondrocyte viability, loss of matrix cationic staining, and features of mechanical instability. Histological features of late graft failures were fracture through the graft, active and incomplete remodelling of the graft bone by the host bone, and resorption of the graft tissue by synovial inflammatory activity at graft edges. Histological features associated with long-term allograft survival included viable chondrocytes, functional preservation of matrix, and complete replacement of the graft bone with the host bone. These long-term histological findings correlate clinically with excellent Oxford Knee Scores (mean 17.5) in age-matched cohorts with allograft transplants surviving 20 (mean 20.9) years or longer.

Conclusion: Given chondrocyte viability, long-term allograft survival depends on graft stability by rigid fixation of host bone to graft bone. With the stable osseous graft base, the hyaline cartilage portion of the allograft can survive and function for 25 years or more.

Lise Malta Janet Ronsky Jason Howard Vicki Komisar Bradley Sauve Rhiannon Evison David Parsons

Purpose: Torso surface topography has reliably detected scoliosis severity. A quantification of torso shape patterns associated with healthy spines is important as a basis for scoliosis screening, monitoring progression, and evaluating treatment methods. The study objective was to examine differences in torso surface geometry associated with age and gender in healthy children.

Method: Seventy normal healthy adolescents were recruited into 3 age groups (8–11, 12–14, 15–18 years), with a goal of equal representation across groups. All consenting subjects met inclusion criterion of no history of back or neuromotor problems, and BMI ≤ 30. Torso surface topography was obtained with Inspeck optical digitizers (InSpeck Ltd., Montreal, PQ) using standard clinical protocols. Subject arm span, height, weight and activity level was recorded. Subjects stood within a positioning frame, while five scans (5s/scan) were acquired. Three-dimensional models of each torso scan were generated. Torso shape was quantified with indices based on established spine-torso shape relations in scoliosis patients. Statistical analyses (p=0.05) were performed for 4 indices: principal axis of orientation, back surface rotation (BSR), rib prominence and quarter area at S1; L3, T12& T7vertebral levels.

Results: Two groups based on gender resulted in similar age distributions with males (Group 1, n = 31) having mean age of 12.76 ± 0.07 years; and females (Group 2, n=39) having mean age 12.64±0.17 years. No statistically significant differences in torso indices were found between the entire female and male groups. When stratified by group, significant differences were obtained between the youngest male group (8–11, n=9) and both the youngest (8–11, n=8) and middle (12–14, n=18) aged females. The quarter surface areas at T7 for the youngest males were statistically significantly different from females of similar age (p=0.036), and from the next older age group (p=0.025). The BSR (p=0.033) and rib prominence (p=0.038) at the L3 level were also significantly different between the youngest males and middle aged females.

Conclusion: General torso shape indice curves can be developed for healthy children, based on a combined database of males and females. However, differences in several torso indices are present between the youngest males and the same and middle age group females.

Ajay Manjoo David Sanders Amit Badhwar Abdel Lawendy

Purpose: This study was designed to determine whether indomethacin, a potent anti-inflammatory agent, reduces muscle damage secondary to elevated ICP.

Method: 16 adult Wistar rats were randomized to 4 groups. In group 1 (control), no intervention occurred. Group 2 (indo) rats were administered indomethacin (12mg/kg) with no elevation of ICP. Group 3 (CS) rats had elevated ICP (30–40mmHg × 45 minutes) using saline injection. Group 4 rats (CS/indo) had elevated ICP and indomethacin administration. After 45 minutes, hindlimb fasciotomy was performed. The extensor digitorum longus muscle was reflected onto an intravital microscope. Capillary perfusion was measured by comparing the number of continuously perfused capillaries to intermittent and non perfused capillaries. Inflammation was determined using the number of activated (rolling and adherent) white blood cells. Muscle cell damage was measured using differential fluorescent staining. Perfusion, inflammation, and muscle damage were compared in all 4 groups using a one-way ANOVA (p< 0.05).

Results: Perfusion: Indomethacin treatment (CS/indo) increased the proportion of intermittently perfused capillaries (39.1 ± 2.2 vs 30.3 ± 2.7) and decreased nonperfused capillaries (38.4 ± 1.8 vs 50.1 ±2.5) compared to CS (p=0.0002). Control and indo groups demonstrated more continuously perfused capillaries compared to CS or CS/indo groups (p0.05).

Conclusion: Treatment of elevated ICP with indomethacin improved microvascular perfusion and reduced cell damage. The protective mechanism of indomethacin is unknown, but may be related to an anti-oxidative and vasodilatory effect. Treatment of elevated intracompartmental pressure with indomethacin dramatically reduces muscle damage and may have important future clinical benefit. Further research is required to determine the mechanism of action.

John Cameron

Purpose: Mal-tracking or dislocation of the patella is often the result of abnormal anatomy. Understanding the anatomy will clarify the treatment options available. The common anatomical causes of dislocation range from the valgus knee to patella alta and external tibial torsion. External tibial torsion results in symptoms ranging from patello-femoral pain to subluzation or dislocation. Many patients become symptomatic after an injury and recognition of the anatomical pathology helps in the treatment decision.

Method: A retrospective study was carried out on 232 rotational high tibial osteotomies in 221 patients operated on between 1990–2004. The pre-operative degree of external tibial torsion and ‘Q’ angle was noted. The extent of any patello-femoral pathology was documented, as well as the degree of correction. Assessment was carried out using the HSS score and the Lysholm score. Notation was made of prior surgery, including arthroscopy, patella tendon tarnsfer and patellectomy.

Results: Of the 232 cases, 80% showed good to excellent results with resolution of patello-femoral pain and instability. Ten percent had residual pain but no instability and 20 cases proceeded to total knee replacement. The best results were seen in cases of pain and instability with minimal patello-femoral arthritis. Some cases with end-stage patello-femoral arthritis were improved with the improvement in quadriceps function via reduction in the ‘Q’ angle.

Conclusion: Rotational osteotomy of the proximal tibia for symptomatic patella instability secondary to significant external tibial torsion results in good to excellent results in 80% of cases.

David Sanders Abdel Lawendy Amit Badhwar Aurelia Bihari

Purpose: This study determined the relative role of inflammation and ischemia in cell damage using an animal model of compartment syndrome.

Method: Forty adult Wistar rats were studied according to a protocol approved by the animal care committee at our institution. Twenty rats were used as control animals, while an additional 20 rats were pretreated with cyclophosphamide to create a leucocyte-deplete state. Animals were anesthetized using 5% isoflurane. Mean arterial pressure was maintained at 80 mm Hg and core temperature was maintained at 36 degrees. Animals were then randomly assigned to one of 4 groups, in which hindlimb compartment pressure was maintained at 30 mm Hg for 0, 15, 45, or 90 minutes. Intravital microscopy was then utilized to study capillary perfusion, white blood cell activation, and cellular damage in the hindlimb EDL muscle.

Results: Inflammation: White blood cell activation was dampened in the neutropenic animals by approximately 85 % at all time periods. Capillary Perfusion: Perfusion was similar between the neutropenic and control animals. Both groups demonstrated a gradual decrease in the number of continuously perfused capillaries, from 80 % at 0 min of elevated intracompartmental pressure (EICP) to 30 % after 90 minutes of EICP. Cellular damage: Cellular damage, measured using a differential staining technique, decreased by 55 % in the neutropenic group after 90 minutes of EICP (p< 0.005).

Conclusion: Compartment syndrome is an important clinical problem resulting in severe muscle damage. In this study, inflammation was confirmed as an important causative element of cell damage. Based upon the results of this study, adjuvant treatment to fasciotomy designed to reduce inflammation and cellular damage may have important clinical benefit.

Kevin Debiparshad Fackson Mwale Peter Roughley Lorraine E. Chalifour John Antoniou

Purpose: It has been shown that ischemic/hypoxic stress as well as shear stress and mechanical injury are linked to the pathogenesis of osteoarthritis. The aim of this study was to determine whether Egr-1 (Early Growth Response protein-1), a transcription factor induced by stress or injury, affects articular cartilage and intervertebral discs (IVDs).

Method: Experimental studies used 6- to 7-month-old adult female wild-type C57Bl/6 or Egr-1-deficient (knockout) mice. All animals were sacrificed at the same age interval (8- to 9-months) and stored at −20°C. Prior to dissection, posterior-anterior and lateral x-rays of whole mice were done. Right knee joint and cervical to lumbar spine were stained with hematoxylineosin (H& E), Safranin-O/Fast green, and Weigert’s hematoxylin/alcian blue/picrosirius red for histological analysis. Bone mineral density (BMD) was measured using a PIXImus Bone Densitometer System. Micro computed tomography (CT) data were acquired on a SkyScan T1072 X-ray Microscope-Microtomograph.

Results: Results showed that the articular cartilage of knee joints of Egr-1 knockout mice was more irregular and degenerative than in the wild type mice. Furthermore, a lower concentration of proteoglycans (predominantly aggrecan) was observed in articular cartilage of knockout mice. The nucleus pulposus (NP) of the knockout mice IVD also showed signs of degeneration and a loss of notochordal cells. The overall disc height was also reduced compared to wild type mice. The number of cells in the endplate was higher in the knockout mice than in the wild type animals. Furthermore, there was a trend for increased lumbar vertebrae BMD as well a significant increase in BMD in the femur of the Egr-1 knockout mice. The relative bone volume (BV/TV) was significantly smaller in Egr-1 knockout mice as was trabecular number and trabecular separation, while there was increased bone surface to bone volume.

Conclusion: Our findings showed signs of degeneration in both articular cartilage and IVD in Egr-1 knockout mice. Moreover, the loss of height in IVD and cellular components of the NP, as well as the increased cell numbers in cartilage of the endplate showed some resemblance to those of human degenerative disc diseases. However, further studies are needed to determine the mechanism by which Egr-1 leads to articular cartilage and IVD degeneration.

Fackson Mwale Caroline N. Demers Arthur Michalek James C. Latridis Tapas Goswami Gilles Beaudoin Lorne Beckman Mauro Alini Davos Platz John Antoniou

Purpose: Since the human intervertebral disc (IVD) is loaded in compression for approximately 16h per day, we investigated the effect of 16h compression loading on the magnetic resonance imaging (MRI) parameters, biochemical contents, and mechanical properties, of IVDs.

Method: Bovine caudal discs (2–3 years-old; non-degenerated) from 3-disc motion segments were injected in the NP with either 5 mg of trypsin in 40 μl Tris buffer or with Tris buffer only. The motion segments were placed in bags containing saline solution and antibiotics and were kept at 37°C throughout the experiment. The motion segments were subjected to either 16h of cyclic compression loading or were left unloaded for 16h. The motion segments were then paraffin embedded for MRI examinations, which were carried out in a 1.5T machine. The IVDs were dissected and the NP and AF were separated for biochemical and mechanical analyses. The NP and AF tissues were analyzed for contents of water, glycosaminoglycan (GAG), total collagen, and denatured collagen. Swelling pressure, compressive modulus HA, and hydraulic permeability were also measured.

Results: Loading had a significant effect on the MRI parameters (T1, T2, T1rho, MTR, ADC) of both the NP and AF tissues. Loading had a greater effect on the MR parameters and biochemical composition of the NP than trypsin. In contrast, trypsin had a larger effect on the mechanical properties. Localized trypsin injection predominantly affected the NP. T1rho was sensitive to loading and correlated with the water content of the NP and AF but not with their proteoglycan content.

Conclusion: Few studies have been directed towards developing an objective and accurate diagnostic tool in the detection and quantification of matrix and mechanical changes in early IVD degeneration. In this report, we demonstrated that MR parameters were influenced by compression loading. We also show showed specific correlations between T1rho and the structural and compositional changes in the disc. Further studies are required to determine the potential of the T1rho technique to be used as a non-invasive diagnostic tool of the biochemical and mechanical changes occurring in disc degeneration.

Kevin Debiparshad Fackson Mwale Peter Roughley Lorraine E. Chalifour John Antoniou

Purpose: Hormone replacement therapy for the menopause seems to be associated with a decrease in the prevalence of symptoms and radiological alterations related to hip and knee osteoarthritis. However, little is known on the effects of estrogen in articular cartilage and intervertebral disc (IVD). The aim of this study was to evaluate the developmental changes in mouse articular cartilage and intervertebral discs under estrogen deficiency.

Method: Experimental studies used 6- to 7-month-old adult female wild-type or bilaterally ovariectomized (OVX) C57Bl/6 mice. All animals were sacrificed at the same age interval (8- to 9-months) and stored at −20°C. Prior to dissection, posterior-anterior and lateral x-rays of whole mice were done. Right knee joint and cervical to lumbar spine were stained with hematoxylineosin (H& E), Safranin-O/Fast green, and Weigert’s hematoxylin/alcian blue/picrosirius red for histological analysis. Bone mineral density (BMD) was measured using a PIXImus Bone Densitometer System. Micro computed tomography (CT) data were acquired on a SkyScan T1072 X-ray Microscope-Microtomograph.

Results: Degeneration, including the loss of notochordal cells, was observed in the nucleus pulposus (NP) of the IVD of OVX mice. The annulus fibrosus (AF) showed marked thinning as compared to the wild type. Furthermore, the OVX group showed decreased IVD heights and trend of endplate ossification. Knee joints of OVX mice showed a trend towards having more gross degenerative changes, like areas of cartilage erosion. A decrease in articular cartilage thickness was also observed. Certain layers of cartilage were more affected than others, suggesting a specific role of estrogens in the developing cartilage. Also, the BMD was reduced in both the femur and lumbar vertebrae of the OVX group. Finally, MicroCT results showed a decrease in percent bone volume, trabecular thickness, trabecular number, and an increase in trabecular separation.

Conclusion: The present study showed AF thinning, decreased IVD height, NP degeneration, and loss of cellular components in the NP in ovariectomized mice. Likewise, the articular cartilage revealed more degenerative changes, including a decrease in articular thickness. Results suggest that estrogens play a role in maintaining healthy cartilage and IVD.

John J. Callaghan Andrew Malin Kevin Bozic Steve Liu Devon Goetz Nicholas Sullivan Scott Kelley

Purpose: Few reports are available at minimum 15 year follow-up of cemented modular cruciate retaining TKA, especially where all polyethylene patella components were utilized. This paper addresses the questions “What is the durability of cemented modular cruciate retaining TKA with all polyethylene patella components at 15 years?” and “Did modular tibial trays demonstrate their utility in terms of the potential for less costly and less complex revisions?”

Method: 101 Press Fit Condylar TKA’s were performed consecutively over a 27 month interval and followed prospectively for a minimum of 15 years. The average age at surgery was 72 years. Clinical Knee Society scores, need for revision, radiographic evidence of loosening, and osteolysis were recorded. All patients were recalled at 5 year intervals.

Results: At minimum 15 year follow-up, 34 patients with 45 knees were living and 40 patients with 54 knees were deceased (one patient [2 knees] was lost to follow-up). 81% of living patients had 15 year radiographs. 6 knees were revised (all related to wear and osteolysis). Average Knee Society clinical scores only deteroriated from 92 points to 89 points between 10 and 15 years.

Conclusion: This cemented modular CR TKA performed well at 15 years with only 6% of knees requiring revision. All revisions occurred after 10 years and were related to wear and osteolysis. 2/3 of the revisions could be salvaged without tibial component revision in this closely followed series. Hopefully these results can be improved with better wear-resistant designs and better quality polyethylene. Especially into the second decade, patients with modular tibial tray TKA constructs should be closely followed to optimize their utility allowing less costly and less complex revisions in cases with polyethylene wear.

Jay A. Katz Nebojsa V. Skrepnik Russell G. Cohen John J. Wild Scott V. Slagis Murray F. Robertson

Purpose: The purpose of this study was to report one year follow-up of clinical and economic results using minimally invasive versus standard techniques for primary TKA. A multi-surgeon, prospective study assessed the one year clinical and economic benefits of MIS versus standard approaches for primary TKA.

Method: Six surgeons, from September 2005 to January 2006, performed a total of 129 TKA cases with 63 patients in the MIS-SV group and 66 patients in the STD group. Data collected included demographic information with BMI, length of hospital stay, hospital cost, discharge disposition, rehabilitation outcomes and Knee Society Scores. Data was collected preoperatively, and at 10 days, six weeks, three months, six months and one year postoperatively

Results: Average LOS was significantly shorter (2.2 days) for MIS-SV group then 3.3 days for STD group. Preoperative range of motion was 1120 for both groups and improved to 1220 (MIS-SV) and 1230 (STD) at one year. Preoperative KSS Functional Scores were 44 for each and improved to 87.6 (MIS-SV) and 86.6 (STD) at one year. Preoperative KSS Knee Scores were 44 (MIS-SV) and 52 (STD). At one year post-operatively, the KSS Knee Score improved to 91.4 (MIS-SV) and 77 (STD). Economically, the MIS-SV procedures averaged $25,076±1,772 and the STD procedure’s mean was $29,928±6,587.

Conclusion: Clinically, no difference between MIS-SV TKA and STD TKA were observed in ROM and KSS Functional score at one year. MIS-SV TKA had a cost savings over STD TKA and KSS Knee Score was significantly better at one year for MIS-SV group

Steven J. MacDonald Kory Charron Robert B. Bourne Richard W. McCalden Douglas D. Naudie Cecil H. Rorabeck

Purpose: Gender specific total knee replacement design has been a recently debated controversial topic. The purpose of this study was to investigate the survivor-ship and clinical outcomes of a large primary total knee arthroplasty cohort, specifically assessing any differences between gender groups.

Method: A consecutive cohort of 3817 patients with osteoarthritis, having undergone 5289 primary total knee replacements (3100-female, 2179-male) with a minimum of 2 years follow-up were evaluated. All surgeries were performed at the same institution by one of four surgeons. Pre-operative scores, latest scores, and change in clinical outcome scores (KSCRS, SF12, WOMAC) were compared and tested for significance using the students t-test. Kaplan Meier (K-M) survivor-ship was determined and tested for significance and categorical variables were compared using chi-squared.

Results: Men were significantly taller and heavier than women, while women had significantly higher BMI’s (p< 0.0001). While men had higher raw scores preoperatively, women demonstrated statistically greater improvement (p< 0.019) in all WOMAC domains including pain (29.87 vs. 27.30), joint stiffness (26.78 vs. 24.26), function (27.21 vs. 23.09) and total scores (28.34 vs. 25.09) There were no gender differences in improvements of the SF12 scores. Men demonstrated statistically greater improvement (p< 0.0001) in Knee Society function (22.10 vs. 18.63) and total scores (70.01 vs. 65.42), but not the Knee Society knee score (47.83 vs. 46.64, p=0.084). K-M cumulative survivorship at 10 years was 87.4±.01 for females and 82.9±.014 for males. K-M survivorship distribution was found to be significantly different between gender groups (p< 0.013, Mantel-Cox, Breslow, Tarone-Ware). Revision rates were 10.2% for males and 8.3% for females which was found to be significant by crosstabs with chi-squared (p=0.006).

Conclusion: In this cohort of patients undergoing total knee replacements, women demonstrated statistically greater implant survivorship, statistically greater improvement in WOMAC scores and less improvement in KSCR scores, leading one to question the hypothesis of an inferior clinical outcome in total knee arthroplasty that is gender based.

Robert B. Bourne B. M. Chesworth A. M. Davis K. D. J. Charron

Purpose: The purpose of this study was to determine the reasons for patient dissatisfaction after primary TKA.

Method: Primary TKA patients (n=2513) entered into the Ontario Joint Replacement Registry (OJRR) with decision date and one year follow-up data (WOMAC, expectations, satisfaction and willingness to undergo surgery) were analyzed to determine the factors that might be associated with patients who were not satisfied with their total knee replacement.

Results: The majority of patients were satisfied with their TKA (n=1939, 81%), but 169 (7%) were uncertain and 281 (12%) were not satisfied. Pre-operative expectations were important as 89% of patients who did not have their expectations met and 40% who had no expectations were dissatisfied with their TKA. Factors that affected patient satisfaction for their TKA, controlling for age, comorbidity and post-operative complications were better pre-operative WOMAC function scores (p25 point improvement).

Conclusion: In this province-wide study, one in five TKA patients were not satisfied with their surgery at one-year follow-up. It is important that patients, surgeons and healthcare payers recognize significant factors that can lead to patient dissatisfaction and help patients establish realistic expectations prior to undergoing TKA surgery.

Khaled J. Saleh William M. Mihalko Thomas E. Brown Quanjun Cui Wendy Novicoff

Purpose: Comorbidities in patients undergoing total joint arthroplasty continue to be a challenging problem. Retrospective studies have demonstrated that co-morbidities affect outcomes of revision total knee arthroplasty (RTKA). However, the relationship between the outcomes of RTKA and co-morbidities has not been well established. This prospective randomized study was undertaken to investigate these relationships.

Method: A prospective cohort study (the North America Knee Arthroplasty Revision Study) was conducted to examine factors that predict outcomes after RTKA. 308 subjects met inclusion/exclusion criteria. Subjects were followed from the time of the index surgery for a minimum of two years to monitor outcomes and complications. Validated quality of life instruments, including SF-36, WOMAC, Knee Society Score, and an activity scale were used. The rates of improvement from 0 to 12 and 12 to 24 months were analyzed.

Results: There were 145 males and 163 females. The mean age was 68.7 years. Mean time from primary procedure to RTKA was 7.9 years. Arthroplasty failure was classified as aseptic in 82% and septic in 18% of the cases. Hypertension was seen in 62.4%, back pain in 50%, heart disease in 25.9%, diabetes mellitus in 23.9%, gastric ulcers in 17.9%, and rheumatoid arthritis in 16.6%. Less frequent co-morbidities included anemia, cancer, kidney disease, lung disease and liver disease.

Conclusion: Analyses showed that the number of reported co-morbidities was the most significant predictor of outcomes, consistently forecasting poorer functional improvement on all measures. The results indicated that ultimate treatment of co-morbidities before and after surgery may improve outcomes of RTKA. Comorbidities in patients undergoing revision TKA can be a challenging problem. This study showed that the number of reported co-morbidities was the most significant predictor of poorer outcomes.

Katherine Gooch Julie Hibbert Hoa Khong Lu Liu Leslie Dort Doug Smith Tracy Wasylak Cyril B. Frank D. William C. Johnston Tim J. Pearce Ron F. Zernicke

Purpose: Elective total hip and knee replacement surgeries are effective procedures for patients suffering from hip and knee disease. The demand for joint replacements is expected to rise as the life expectancy of Canadians increases; thus putting a heavy burden on healthcare. In an effort to reduce the acute hospital length of stay (LOS) the Alberta Orthopaedic Society, with the Alberta Bone and Joint Health Institute, three Alberta health regions (Calgary, Capital and David Thompson) and Alberta Health and Wellness created an evidence based new care continuum for hip and knee replacement. The LOS through the new care continuum compared to the current conventional approach was evaluated. In addition patient characteristics that could potentially predict the LOS were evaluated.

Method: The study design was a randomized, controlled trial. Consenting subjects were randomized to receive care through either the new care continuum (intervention) or the existing “current conventional approach” (control). Acute hospital LOS was calculated as the difference between the date and time the patient was admitted to the date and time the patient was discharged. Data was collected on patient characteristics potentially associated with acute hospital LOS.

Results: Intervention patients demonstrated a significantly shorter acute hospital LOS than the control patients, 4.66 and 5.95 days respectively. Further analysis of the data using a generalized linear model indicated that several patient characteristics were associated with a shorter/longer wait for consultation and surgery. Married patients had a statistically significant shorter LOS than single patients (IRR=0.89, p=0.001). Whereas older patients (IRR=1.01, p=< 0.001), patients with increased comorbidity (IRR= 1.03, p=0.001), and patients with an ASA of ≥ 3 (IRR= 1.22, p=< 0.001) resulted in a significantly longer LOS.

Conclusion: This study indicated that an evidence based healthcare continuum for the delivery of hip and knee replacements was successful in significantly reducing acute care LOS. Reducing the LOS using the new care continuum could potentially help alleviate the strain on limited healthcare resources and the savings could be reinvested to increase the numbers of joint replacement performed. Furthermore, an understanding of patient characteristics that influence acute hospital care LOS should be used to model surgical case mixing to further improve efficiencies.

Stéphane Pelet Anne-Marie Bédard Luc Bédard

Purpose: TKR is a frequent surgical procedure with significant post-operative pain, requiring lot of opiates. Side effects are frequent and can modify post-operative rehabilitation. The goal of the study is to determine if the adjunction to a femoral block of intra-articular ropivacaïne can diminish the use of opiates and then gives better clinical results. The main clinical outcome is the opiate consumption at 48 h.

Method: 80 consecutive patients admitted for TKR were randomized in the 2 groups (ropivacaïne vs control), surgeon, patient and clinical evaluator are blinded. Femoral block was performed and controlled for efficacy before surgery. Intra-articular injection of ropivacaïne or saline was delivered prior to wound closure with a catheter. Opiates were delivered with an ACP for 48 h. Rehabilitation was the same in the 2 groups.

Results: We found no differences between the 2 groups in the opiate consumption at 24 and 48 h (p> 0,5). There was even an increase in opiate use in the experimental group, that couldn’t be explained by other factors (age, weight, surgical time, surgical tourniquet time, sex). There was no differences in ROM, hospital stay, side effects and EVA.

Conclusion: There is no indication for the adjunction of intra-articular ropivacaïne to a femoral block after TKR. Other issues as combined blocks or other types of infiltrations (posterior capsule for example) could be considered in new trials to diminish pain after TKR.

Santosh Venkatachalam Chellappan Sivaji Greg J. Packer Allison Shipton

Purpose: The aim of this nonrandomised retrospective study was to compare the results of anterior plating with superior plating in acute mid-shaft clavicular fractures.

Method: From 2000–2005, 49 fresh midshaft clavicular fractures in adults with shortening of > 20mm on the radiographs were treated with reconstruction plates. The placement of the plate on the clavicular surface was based on the preference of the surgeon operating. Patients were discharged within a day or two of the operation depending on pain control and were allowed to mobilise their shoulder within pain limits. They were followed up at six weeks and 12 weeks post operation and were allowed to return to work by 12 weeks if there was clinical and radiological signs of union. There were 22 patients in the anterior and 27 in the superior group. The mean age in the anterior was 36.3 years and 37.6 in the superior group. Majority(65%) of the fractures were sustained following RTA.77% were involved on the dominant side in both groups. The percent of patients in light and heavy manual work were similar in both groups. Follow up varied from six months to 24 months. Functional outcome was analysed by the physiotherapist with Biodex machine using Constant score and patient satisfaction questionnaire.

Results: There was no significant difference in Constant scores (Anterior=89, Superior=86), patient satisfaction with operation, return to activity and occupation in either groups. There was a total of six implant removals out of which five were in the superior group due to prominent metalware. There were two implant failures between six to 12 weeks post operation, both of which were in the superior group which were replated anteriorly. There was no significant difference in the deep/superficial infection in either groups. Return to work and satisfaction with operation were similar in both groups.

Conclusion: In our study, the incidence of hardware failure and hardware removal was significantly higher in the superior group compared to anterior group. Necessity for hardware removal becomes low as the anteriorly placed plate is less prominent. Also the risk of injuring the important neurovascular structures is less while drilling holes from anterior to posterior compared to superior to inferior direction. Hence we recommend anterior plating of the clavicle as a better method compared to superior plating of the clavicle.

Robert J. Feibel Paul R. Kim Paul E. Beaule Geoffrey F. Dervin

Purpose: Multi-modal therapy remains the cornerstone of post-operative pain management following knee replacement surgery. Femoral nerve catheters and blocks have been used with success in the management of post-operative pain yet most practicing arthroplasty surgeons and anaesthesiologists are unaware of the potential complications and risks of the procedure. The purpose of this study is to report on the complications associated with these techniques following knee replacement surgery.

Method: One thousand one hundred and ninety patients underwent knee replacement surgery between January 2004 and July 1, 2007 and received an indwelling continuous infusion femoral catheter for post-operative marcaine pump infusion. For the initial 469 patients (Group 1), the continuous infusion ran for 2 to 3 days. In 721 patients, the continuous infusion was discontinued 12 hours following surgery (Group 2).

Results: There were 15 major complications observed in 1190 patients: 7 femoral nerve palsies (2 in Group 1, 5 in Group 2) and 8 falls (4 in each group). For the patients who had fallen in hospital, the injuries sustained were: traumatic hemarthrosis, hemarthrosis requiring arthrotomy, major wound dehiscence with exposed implants, complete medial collateral ligament rupture requiring repair, quadriceps tendon rupture requiring delayed repair, minor wound dehiscence with suture, and displaced ankle fracture.

Conclusion: Femoral nerve catheters and blocks are effective tools for post-operative pain relief following knee arthroplasty surgery. However, it is important for the surgeon and anaesthesiologist to provide information regarding the potential complications of the treatment as part of an informed consent. Although the complication rate is relatively low at 1.3%, the occurrence of femoral nerve palsies as well as re-operations significantly delayed patient recovery. We did not observe a benefit in terms relative risk reduction with discontinuation of the continuous infusion 12 hours following surgery. The femoral palsies reported in our series have led our institution to adopt ultrasound guidance for catheter placement rather than tradition nerve stimulation technique, although the safety of this newer technique is currently under evaluation.

Michael D. McKee Charles Thompson Lisa Wild Emil H. Schemitsch

Purpose: In a prospective randomized clinical trial, we have previously reported the “limb-specific” results comparing operative (plate fixation) versus non-operative (sling) treatment for completely displaced fractures of the shaft of the clavicle. We also sought to determine the effect that a fracture of the shaft of the clavicle had on general health status, as measured by the SF-36 General Health Status instrument. We then evaluated the effects of different treatment methods (operative versus non-operative), on general health scores.

Method: We performed a multi-center, randomized clinical trial of operative versus non-operative treatment of completely displaced clavicular shaft fractures in 111 patients. In addition to radiographic, surgeon-based, and limb-specific data we prospectively gathered SF-36 questionnaires at baseline, and at 6 weeks and 3, 6, 12, and 24 months post-injury.

Results: Results: Both groups had SF-36 scores equivalent to or slightly superior to population norms at baseline. A clavicular shaft fracture had a significant negative effect on SF-36 scores (especially the physical components) in both groups at 6 weeks (p< 0.01) and 3 months (p< 0.01). There was a statistically greater decrease in Physical Component Scores (PCS) in the non-operative group compared to the operative group (P< 0.05). At 6 months, scores had returned to pre-operative levels in the operative group, but remained significantly decreased in the non-operative group (p=0.04). This difference persisted at the one and two year points.

Conclusion: A displaced fracture of the clavicular shaft has a clinically significant negative effect on general health status scores. This effect can be mitigated by primary operative fixation, which restores scores to normal levels by six months post-injury. Patients treated non-operatively for a displaced fracture of the shaft of the clavicle demonstrated lower PCS scores at two years post-injury. This information is useful in counseling patients with regards to treatment options following displaced fractures of the clavicle shaft.

George Russell Robert Dews Scott Porter Matthew Graves

Purpose: Displaced acetabular fractures require operative intervention for optimal results. Obesity and morbid obesity is becoming more prevalent. Morbid obesity is defined as a body-mass index (BMI) > 40. The purpose of this investigation is to evaluate the early results of operative treatment of acetabular fractures in morbidly obese patients.

Method: A prospectively gathered database demonstrated 349 patients who underwent ORIF for acetabular fractures over a 60 month period. Of those patients, 39 were morbidly obese. Patient weights were collected from anesthesia records. There were 15 posterior wall, 10 transverse/posterior wall, 5 T-type, 3 transverse, 3 anterior column/posterior hemi-transverse, 1 anterior column, 1 posterior column/posterior wall, and 1 both column fractures. Early results of morbidly obese patients (Group 1) were reviewed. Perioperative complications were compared to patients with BMI < 40 (Group 2). Factors evaluated were: estimated blood loss, operative time, length of hospital stay, and overall complication rate (as defined by wound complications or heterotopic ossification requiring subsequent surgery, failure of fixation, nerve palsy, death).

Results: Follow up ranged from 6–48 months. Fracture reductions were perfect in 23, imperfect in 10, and poor in 6. Fixation failure was noted in 9 patients and typically associated with comminuted posterior wall fractures. Eight patients developed deep infections necessitating debridements. Nine patients required secondary surgery for wound healing problems. Of those, 6 required one additional surgery, three required 2, two required 3, one required 5, and one required 12 additional surgeries. Six patients proceeded to THA and two of those required revisions. The average EBL was 903cc in group 1 versus 630cc in group 2 (p < 0.044). Operative time averaged 293 minutes in group 1 versus 250 in group 2 (p< 0.008). Hospital stay for group 1 averaged 26 days versus 15 days in group 2 (p< 0.008). Complication rate for group 1 was 67% versus 16% in group 2.

Conclusion: This data shows that there is a significant increase in estimated blood loss, operative time, and length of hospital stay. Moreover, the risk of complications should be heavily weighed prior to operative intervention

George Russell Matt L. Graves Scott Porter Michael Archdeacon David P. Barei Andy Brien

Purpose: Treatment of complex diaphyseal malunions is challenging. It requires extensive preoperative planning and precise operative technique. A single technique has not been generalizable secondary to the limitations of each type of osteotomy. A simpler method was developed to manage these deformities.

Method: Ten patients with complex diaphyseal mal-unions (4 femoral, 6 tibial) underwent a clamshell osteotomy. Indications for surgery included pain at adjacent joints and deformity. Preoperative evaluation included deformity characterization. The malunited segment was identified on biplanar radiographs. After exposure the malunited segment was transected perpendicular to the normal diaphysis proximally and distally. The transected segment was again osteotomized about its long axis and wedged open with a lamina spreader, similar to opening a clamshell. The surgical approach was sealed to retain the subsequent reamings. The proximal and distal segments of the diaphysis were aligned using the intramedullary nail as an anatomic axis template and the opposite extremity as a length and rotation template. Partial weight-bearing mobilization with crutches began immediately and progressed based on clinical and radiographic evaluation. Followup ranged from 6–52 months.

Results: Radiographic angular corrections were complete in each case and ranged from 2–20 degrees in the coronal plane, 0–32 degrees in the sagittal plane, and 0–25 degrees in the axial plane (rotation). Correction of length ranged from 0–5 centimeters, restoring leg length to within 2 centimeters in all cases. All osteotomies were healed both clinically and radiographically by 6 months. All patients were ambulatory without assistive devices by the time of the most recent followup.

Conclusion: The proposed osteotomy provides a generalizable way to correct many forms of diaphyseal mal-unions by acting as a bypass in realigning the anatomic axis of the long bone using a reamed intramedullary nail as a template.

Stéphane Pelet Jean Lamontagne

Purpose: The main treatment for unstable distal radius fracture in Québec consists in pinning and cast, with secondary shortening and displacement responsible for lack of motion. The goal of the study is to compare clinical and radiological results after treatment with non-bridging external fixator compared to pinning and cast, with restoration of grip strength as main clinical outcome.

Method: Between June 2003 and June 2005, 120 consecutive patients admitted for unstable extra-articular distal radius fracture were randomized in the 2 groups. Early mobilisation was allowed in the group with external fixator, and patients in the other group had pins and cast for 6 weeks. Follow-up was completed after 6 months with determination of clinical and radiological data for the both wrists. 110 patients completed the study, with 2 comparative groups for epidemiologic and radiological criteria (n = 63 for pins and 57 for external fixator).

Results: Grip strength was significantly better in the fixator group at 3 months (68,36%;p< 0,001) and 6 months (98,26%;p< 0,001). Active ROM was better and obtained earlier in the fixator group in all directions (p< 0,001). Fixator prevent shortening and secondary displacement in a highly significant way (p< 0,001). No difference in pain medication, but fixator group could begin occupation earlier (p< 0,001).

Conclusion: Non-bridging external fixator is a treatment of choice for unstable extra-articular distal radius fractures. The immediate stability allows in all patients (without influence of age, bone quality or fracture displacement) early mobilisation, prevent secondary displacement, and gives earlier and better functional results.

Paul Tornetta Jodi Siegel Peter Burke Neema Kaseje Suresh Agarwal Jorge Soto Stephan Anderson

Purpose: In patients with pelvic trauma, the need to quickly and accurately rule out sources of bleeding is paramount. We sought to determine the predictive value of CT angiography in determining the need for therapeutic angiography and to ascertain if definable arterial bleeding correlated with anatomic injury.

Method: Over a 2 year period 58 patients with a high-energy mechanism and pelvic injury underwent pelvic CT angiography as part of their initial trauma CT scan. This was performed as a 25 second delayed scan (after contrast introduction) using a GE light speed VCT64 scanner. The decision to proceed to therapeutic angiography was made on clinical grounds and was later compared with the CT angiographic findings. The anatomic location of bleeding on CT angio and interventional angio were compared.

Results: There were 36 male and 22 female patients, aged 43 (17 – 86), with average ISS of 18.6. The 18 (31%) patients with positive extravasation on CT angiography had higher initial blood requirements compared to those without extravasation. Two of the CT(+) group died prior to therapeutic angiography being performed. 11 of the remaining 16 had interventional angiography; 8 had (+) findings, including 7 major vessels coiled and 1 cutoff vessel observed. 1 patient of 40 with negative CT angiogram met clinical criteria had an interventional angiography; no arterial bleeding was discovered. The negative predictive value of CT angiography for pelvic arterial bleeding requiring therapeutic angiography was 100%; the positive predictive value of angiographically treatable bleeding was 70% (counting the two early deaths). The vessel location on CT angio and therapeutic angio was consistent in all cases. The CT angio (+) group had a higher percentage of unstable pelvic injuries (67% vs. 40%).

Conclusion: In this pilot study, CT angiography added to the initial trauma scan in patients with pelvic trauma demonstrated a 100% NPV for arterial bleeding that required therapeutic angiography on clinical grounds. Positive findings correlated well with the anatomic location of pelvic injury and had a 70% PPV for angio-graphically treatable bleeding. Further study of this technique is warranted.

David Sanders Riley Campbell Mark MacLeod Christina Tieszer

Purpose: To compare the reoperation rates of three commonly used forms of fixation for distal femur fractures.

Method: 89 patients treated between 2002 and 2006 were retrospectively reviewed (mean follow up 28 months).. 40 fractures were treated with an intramedullary nail (IMN), 34 with the LISS internal fixator and 16 with a DCS construct. Patients were reviewed clinically and radiographically. The primary treatment outcome was the rate of secondary surgical intervention; secondary outcomes included radiographic alignment and clinical outcome measures (LEM and SF-36).

Results: Reoperation: Reoperation rate for the DCS group was 12.5%, compared to 17.5 % in the IMN group and 44 % in the LISS group. Failure rates were the same when only AO type C fractures were considered. Most concerning in the LISS group was the rate of failure in distal short oblique type A fractures, in which catastrophic failure was observed in 4 of 9 patients. Alignment was similar comparing all three groups; the average radiographic distal femoral articular angle (DFAA) of was 10 degrees valgus in the DCS group, compared to 8 degrees in the IMN group and the LISS patients.

Conclusion: Reoperation rate was highest in this study when the LISS fixator was used for distal short oblique fractures of the femur. These fractures may benefit from fixation which achieves direct interfragmentary compression, such as an intramedullary device or compression plating.

Paul Tornetta Andrew Freeman Andrew Schmidt Joan Bechtold William Ricci Mark Flemming

Purpose: Locked plating has become a commonly used technique in complex fracture and nonunion work. The combination of locked and unlocked screws in the same construct has been referred to as “hybrid” fixation. Little work is available to direct the specifics of this fixation method. The purpose of this study was to determine the relative contribution of the number and location of locked screws on the properties of hybrid plate constructs in an osteoporotic bone model.

Method: A prefabricated osteoporotic model was used for reproducibility (composite cylinders 35 mm in diameter and consisting of a 2.5 mm fiberglass shell filled with 10 lb/ft3 polyurethane). A 5mm gap model was used, and fixed with a 12 hole plate. Six different constructs were tested including 2 unlocked and 4 hybrid configurations. All screws were bicortical and placed with 4Nm of torque. Baseline removal (loosening) torque was recorded for each screw for comparison with removal torque after cyclic loading. Testing was performed with ±8Nm of torsional load and run to 100,000 cycles. Stiffness of each construct was measured at 10,000 cycle increments and the removal torque of each screw was recorded at the conclusion of the 100,000 cycles.

Results: Stiffness of the constructs was most affected by the number of screws. No effect was seen with the replacement of one or two unlocked screws with locked screws on each side of the gap. Replacement of three unlocked screws with locked screws increased the stiffness of the construct (p< 0.001).

Conclusion: At least three bicortical locked screws on each side of a construct are needed to increase the stiffness and decrease the loss of stiffness over 100,000 cycles of torsional stress in an osteoporotic surrogate model. Locked screws placed between the fracture and unlocked screws protect the unlocked screws from loosening and may have some clinical utility in fatigue of the construct.

Mary Rose Cunningham Martin Quirno John Bendo Jonathan Steiber

Purpose: Facet joint arthrosis is an entity that can have a key role in the etiology of low back pain, especially with hyperextension, and is a key component of surgical planning, especially when considering disc arthroplasty. Plain films and MRI are most commonly utilized as the initial imaging of choice for low back pain, but these methods may not truly allow an accurate assessment of facet arthosis. Our purpose was to observe the inter- and intraobserver reliability of utilizing CT and MRI to evaluate facet arthrosis, the inter- and intraobserver reliability of the facet grading system, and the agreement of surgeons as to when to perform disc arthroplasty after the lumbar facets are evaluated.

Method: A power analysis was performed which showed we would need 6 reviewers and 43 images to have 80% power to show excellent reliability. 102 CT and the corresponding MRI images of lumbar facets were obtained from patients who were to undergo lumbar spine surgery of any type. 10 spine surgeons and 3 spine fellows reviewed the randomized images at 2 time points, 3 months apart, graded the facet arthosis as well as indicated whether they would chose to perform a disc arthroplasty based on the amount of facet arthrosis. Both interobserver and intraobserver kappa values were calculated by result comparison between observers at the two time points and between CT and MRI images from the same patient.

Results: interobserver reliability for MRI was 0.21 and 0.07(fair to slight agreement), and for CT was 0.33 and 0.27(fair agreement), for the spine surgeons and spine fellows respectively. The mean intraobserver reliability for MRI was 0.36 and 0.26 (fair agreement) and for CT was 0.52 and 0.51 (moderate agreement). The kappa value for agreement of whether to perform a disc arthroplasty after grading the facet arthrosis utilizing MRI was 0.22 (fair agreement) and utilizing CT was 0.33 (fair agreement) among the senior spine surgeons.

Conclusion: The existing grading system for facet arthrosis and of whether to perform a disc arthroplasty utilizing the grading system has at best only fair agreement. CT is more reliable for grading facet arthrosis.

Daniel J. Sucato Bryan Tompkins Anna McClung

Purpose: The Lenke classification has established criteria which designate the proximal thoracic (PT) curve as structural (Lenke 2). However, this classification may overestimate the necessity to include the proximal thoracic curve in the fusion construct. The objective of this study was to compare the incidence of fusing the PT curve for true Lenke 2 curve patterns, comparing a time period when the classification was not utilized and when it was first used.

Method: A retrospective review of a consecutive series of patients with adolescent idiopathic scoliosis (AIS) at a single institution from 1996–2000 (early group) and from 2002–2004 (late group) were reviewed. The curves were all classified by the Lenke classification retrospectively. Patients were also grouped into those who have had inclusion of the PT curve (+PT fusion) and those who did not (−PT fusion).

Results: There were 44 in the early group and 33 in the late group. There were no differences in the early and late groups with respect to age (14.3 vs. 14.4yrs), gender (79.5% vs. 69.7% female), BMI (21.7 vs. 22.4kg/cm2), the preoperative PT magnitude (40.0° vs. 38.6°), curve flexibility (16.0% vs. 14.5%), the main thoracic (MT) magnitude (63.4° vs. 62.7°), T1 tilt (7.3° vs. 5.2°), pre-operative clavicle angle (1.0° vs. −0.2°), and preoperative shoulder height (1.2 vs. −0.8mm. The early group had fusion of the PT less often (36% vs. 57%)(p< 0.05) which resulted in a greater residual PT curve (26.5 vs. 22.2°), MT curve (33.8 vs. 27.8°), and a greater clavicle angle (4.6 vs. 2.5°)(p< 0.05). At two years the PT continued to be significantly greater in the early group (28.6 vs. 22.8°)(p< 0.05), however T1 tilt (8.8 vs. 8.1°), clavicle angle (1.3 vs. 1.0°), and shoulder height (3.5 vs. 4.7mm) were the same.

Conclusion: The application of the Lenke classification system for AIS increases the likelihood of instrumenting a PT curve resulting in improved postoperative PT curve magnitude. However, similar shoulder balance, T1 tilt and clavicle angle were seen compared between groups. The classification system should be used to guide decision making, however, other parameters should be evaluated when deciding when to instrument a PT curve.

Rena Lorraine Stewart James Stannard David Volgas Justin Duke Jason Piefer

Purpose: Fractures of the calcaneus remain a significant clinical challenge. Little study has been done to investigate the potential benefit of bone graft in the treatment of these fractures. The purpose of this study is to compare the clinical outcome of calcaneus fractures treated with and without ICBG.

Method: In an ongoing study at a Level I Trauma Center 45 patients with calcaneus fractures requiring operative management were enrolled in a prospective, randomized study. 24 patients were randomized to ORIF without graft (control) and 24 patients were randomized to ORIF with ICBG (study group). Demographic, intra-operative and long term clinical outcome data was collected. Outcome measures included pain scores, Creighton-Nebraska Foot Scores, time to weight bearing, return to work and wound complications.

Results: The groups showed no differences in gender, age, mechanism of injury, fracture classification or time to surgery (avg. 12 days). Tscherne scores at presentation differed, with higher average scores in the control group. There were 2 open fractures in each group. The groups showed no statistically significant differences in any of the clinical outcome measures. There was no difference in pain scores (control mean 2.6 vs. study mean 4.1, p = 0.1), Creighton-Nebraska Scores (control 71 vs. study 55, p = 0.1), time to weight bearing (control 2.6 months vs. study 2.7 months, p = 0.9). At 6 months 38% of controls had returned to work (with 87% of those returning to the some occupation) while 39% of the study group returned to work (71% to same occupation). An overall wound complication rate of 27% was seen with 30% of controls and 24% of study patients exhibiting wound issues.

Conclusion: In this prospective randomized study, patients treated with ORIF for calcaneus fractures showed no difference in clinical outcomes with or without the addition of ICBG. No clear benefit is demonstrated to warrant the additional operative time, pain and possible complications that have been previously documented to be associated with ICBG.

Maurice Tom-Pack Simon Dagenais Parham Daneshvar Eugene Kenneth Wai Lynn Ashdown

Purpose: The goal of laminectomy is to relieve spinal stenosis and improve radiculopathy. Back pain related to poor trunk muscular conditioning may negatively affect post-operative outcomes. A better understanding of this relationship is important to improve the selection of appropriate surgical candidates. The purpose of this study was to assess the association between cross-sectional lumbar paraspinal muscle area as measured by CT or MRI and outcomes following laminectomy.

Method: Prospective observational study of 23 patients undergoing primary elective lumbar laminectomy without fusion who were assessed with pre-operative CT scans. Clinical outcomes were measured with Numerical Pain Scale (NPS) for back and leg pain and the Oswestry Low Back Disability Index (ODI) at baseline and follow-up at a minimum of one year. Lumbar paraspinal muscle cross-sectional area was measured using digital imaging software and adjusted for percent fat infiltration; CT scans evaluations were blinded to clinical outcomes.

Results: There were significant improvements in clinical outcomes following laminectomy. ODI decreased from 53.9±11.8 (mean±standard deviation) at baseline to 27.3±20.6 after a follow-up of 15.2±3.5 months. A strong correlation existed between cross-sectional lumbar paraspinal muscle area after adjusting for infiltrating fat content an improvement in ODI (r=0.51, p< 0.02) or back pain NPS (r=0.55, p< 0.02). These relationships remained statistically significant after adjusting for age and body mass index. No significant associations were identified for improvements in leg pain NPS.

Conclusion: This study suggests a possible relationship between cross-sectional lumbar paraspinal muscle area and outcomes following laminectomy. This raises important questions regarding the role of trunk muscular conditioning in the etiology of back pain and success of surgery. Further research is required to refine this measurement as a tool to improve patient selection for surgery.

Stefan Parent Zhi Wang Jean-Marc Mac-Thiong Yvan Petit Hubert Labelle

Purpose: To determine the relationship between sacral morphology and developmental L5/S1 spondylolisthesis in children and adolescent.

Method: A radiographic study was conducted to investigate sacral morphology in developmental L5/S1 spondylolisthesis in a pediatric and adolescent population. The lateral standing radiographs of 131 subjects, aged 6 to 20 years old with developmental L5-S1 spondylolisthesis (91 low grade and 40 high grade) were analyzed with a dedicated software allowing to measure the following parameters, which were analyzed for each subject by the same individual and compared to an age and sex-matched cohort of 120 asymptomatic subjects: the sacral table index (STI), the sacral table angle (STA), the sacral kyphosis (SK), S1 superior angle, S2 inferior angle, and grade of spondylolisthesis. Student t tests were used to compare the parameters between the curve types.

Results: This study demonstrated that STA is significantly smaller (p< 0.01) in children and adolescents with L5-S1 spondylolisthesis compared to a similar control group. Furthermore, STA is significantly smaller in high grade spondylolisthesis when compared to subjects with low grade. There is also a significant difference in segmental sacral morphology (S1 and S2 anatomy) in the spondylolisthesis group. Increasing sacral kyphosis is also found to be significantly associated with spondylolisthesis.

Conclusion: The sagittal sacral morphology is a constant anatomic variable specific to each normal individual. The anatomy of the sacrum in children and aldolescentss with L5-S1 spondylolisthesis is particular and different from a control group. This study suggests that sacral anatomy may have a direct influence on the development of spondylolisthesis: a lower STA and higher sacral kyphosis may be two factors predisposing to vertebral slip in developmental spondylolisthesis.

Joseph D. Smucker John A. Bobst Emily Petersen Douglas Fredericks

Purpose: B2A2-K-NS (B2A) is a synthetic receptor-targeted peptide that appears to amplify the biological response to rhBMP-2. In ectopic sites in vivo, B2A augments bony mineralization when combined with demineralized bone matrix. The purpose of this study was to determine if the synthetic peptide B2A2-K-NS coated on osteoconductive granules (B2A/G) enhances autograft fusion in a rabbit bilateral posterolateral spine fusion model.

Method: Sixty skeletally mature New Zealand White Rabbits weighing 4.5–5.5 kg were entered into the study (IACUC #0511251). A single-level, bilateral posterolateral intertransverse process fusion was performed at L4-L5 with autogenous bone or an osteoconductive granule containing several coating concentrations of B2A. Animals were euthanized at 6 weeks post surgery.

Results: Gross examination of the surrounding soft tissues and grafted area showed no adverse reactions to the osteoconductive granules with or without B2A. Radiographic fusion rates were similar to palpation fusion rates across all groups. When assessed by palpation, animals treated with 300 μg B2A/G had 80% fusion while those treated with 100 μg B2A/G (89%) and 50 μg B2A/G had 78% fusion. Animals receiving 0 μg B2A/G (granules only) had a fusion rate of 33% and autograft only animals had a fusion rate of 63%.

Conclusion: In this model the B2A/G composition appeared to function as a graft enhancer and be more efficacious than autograft alone in this model. B2A peptide has a unique mechanism of action in that although it interacts with receptors for BMP-2, the action is mediated only in the presence of BMP-2 or an osteoinductive event. In this model, the decorticated TP and/or autogenous bone may have provided the necessary signals for B2A. These results suggest that B2A/G should be further investigated to determine mechanistic effects and clinical applications

Paul Slosar Jim A. Youssef James Reynolds Catherine A. Patty Darrel Brodke

Purpose: Few opportunities exist for physicians to easily obtain immediate insights or solicit direct advice from a respected peer on a complicated case. As a result, physicians end up relying heavily on journals, textbooks, and other dated resources that may prove to be dated or inadequate in addressing unique patient problems. Furthermore, the typical training modules available are limited to a one- or two-day experience. Often times this situation does not provide an adequate understanding of the surgical indications, techniques, and potential complications in the application of new technology. Consequently, many surgeons fail to adopt new technologies due to their lack of understanding of the application of such novel technologies. Recently, Reynolds et al studied the effect of peer collaboration among surgeons at a weekly surgery conference. They found that changes in surgical decision-making occurred in 12.5% of all cases reviewed and in 20% of the complex cases. However, collaboration should not be limited to weekly meetings or annual conferences. The Internet has introduced Collaborative Knowledge Networks (CKNs) that allow communities of surgeons to collaborate virtually on complex patient cases—allowing for rapid, bidirectional information. SpineConnect has surfaced as an example of a CKN that allows orthopedic spine surgeons to discuss surgical decisions.

Method: We studied the use of Internet collaboration among spine surgeons using the SpineConnect website. We also compared the improvement in the adoption rate of novel technologies using technology fellowships versus traditional training modules. These fellowships use both in-person and virtual collaboration through the Spine-Connect platform as a new means of training physicians.

Results: Using the SpineConnect website, surgical decision-making and planning was altered in 34% of active users and 90% agreed that the ability to collaborate with their peers, using a dedicated website, has improved their ability to practice spinal surgery. Continuous communication and dialogue resulting from the technology training fellowships encouraged better understanding of surgical indications, a greater comprehension of surgical technique, and a mechanism to discuss and solve complications. When such fellowships were implemented, we found a 30% improvement in adoption rate over traditional training modules.

Conclusion: The treatment of spine surgery patients has benefited from the utilization of collaborative platforms such as SpineConnect. In spine surgeon training and education, we found that CKNs promoted better surgical decision-making and increased understanding of new technology application.

Eugene Wai Seyon Sathiaseelan Tom Polis Robin Cardman Donald Chow Garth E. Johnson Joseph O’Neil

Purpose: Harvesting of iliac crest graft for spinal fusions is associated with a number of patients reporting residual pain at the harvest site. Various interventions have been proposed to minimize the pain associated with this. The purpose of this study was to evaluate the efficacy of intra-operative infiltration of morphine into the iliac crest harvest site for reduction of postoperative pain.

Method: A double-blinded, placebo controlled study was performed comparing intraoperative infiltration of 5mg of morphine (treatment) vs. saline (placebo) into the iliac crest harvest site for patients undergoing elective spinal surgery. Patients with myelopathy, excessive preoperative opiod use (60mg equivalent morphine/day or more), or multilevel (greater than 3 levels) spinal surgery were excluded. Postoperative administration of morphine (recovery room and PCA) was standardized. Numerical pain scores specific for the iliac crest site were determined in the immediate postoperative period and at 3, 6 and 12 months. Ad hoc power analysis demonstrated that 36 patients would be able to detect a clinically significant difference of 2.4 points on a 10 point numerical pain scale (alpha = 0.05, power = 80%).

Results: 37 patients were randomized and evaluated with a minimum of one year follow-up. The groups were similar in baseline age, gender and comorbidity. There was no significant difference between groups in total use of postoperative morphine during the first 24 hours (treatment: 320mg +/− 268mg, placebo: 293mg +/− 182mg, p = 0.73). There was no significant difference in iliac crest activity pain scores at 1 year (treatment: 1.7 +/− 3.0, placebo: 1.1 +/− 2.4, p = 0.48) or at any of the earlier time points. The proportion of patients with moderate to severe iliac crest pain at one year follow-up was the same between both groups.

Conclusion: This study has demonstrated that there are no additional benefits for the use of intra-operative infiltration of morphine into the iliac crest harvest site during spinal fusions.

Michael P. Bolognesi Nicholas A. Viens Milford H. Marchant Thomas Parker Vail Chad Cook

Purpose: As the prevalence of diabetes mellitus (DM) in people over 60 years of age is expected to increase, the number of diabetic patients who undergo total hip and knee arthroplasty should increase concordantly. In general, patients with DM have significantly increased risk for adverse events following arthroplasty. The goal of this study was to determine whether the quality of glycemic control affected the incidence of perioperative complications in the hospital following joint replacement.

Method: From 1988 to 2003, the Nationwide Inpatient Survey (NIS) recognized 65,769 patients who had DM and underwent joint replacement surgery. In this retrospective study, bivariate and multivariate analyses compared patients with uncontrolled (n=2,872) and not uncontrolled (n=62,897) DM regarding common surgical and systemic complications, mortality, and hospital course alterations. Glycemic control was determined by physicians’ assessments based upon the American Diabetes Association guidelines using a combination of patients’ self-monitoring of blood-glucose testing, the hemoglobin A1C, and related complications.

Results: Patients with uncontrolled DM routinely had an increased length of stay and increased inflation-adjusted costs after surgery (p< 0.001). Uncontrolled patients also had significant increases in the incidence of stroke, pneumonia, urinary tract infection, post-operative hemorrhage, wound infection, and death (p< 0.001).

Conclusion: Patients with well-managed glycemic control have fewer comorbidities in general. Patients with uncontrolled DM exhibited significantly increased risks for surgical and systemic complications, higher mortality, increased length of stay, and higher hospital charges during the index hospitalization following arthroplasty. The consequences are increased cost, greater burden on the healthcare system, and greater risk to these patients.

Stephen Croft Peter Rockwood

Purpose: Intra-articular (IA) steroid injections have been widely used by orthopedic surgeons as symptomatic relief for severe hip OA, and with the addition of local anesthetic, they can be used to differentiate pain from the hip, knee and lumbar spine. This technique has come under some question as of late however due to inconsistencies in the literature. It has been reported that there is an association between infection post Total Hip Arthroplasty (THA) and prior IA steroid injections (Kaspar & de Beer, 2005). Additionally, the incidence of infections has been noted to particularly rise when the injections occur within six weeks of the operation (McIntosh et al, 2006). This study was used to analyze the risk of intra-articular steroid injections with respect to infection following THA.

Method: We retrospectively reviewed 96 hips of patients who underwent total hip arthroplasty between 2001 and 2007 by one surgeon. Matched cohorts of 48 hips were established: one group in which patients received an injection prior to THA and one in which patients did not. Statistical analysis was performed using SPSS V14. Exclusion criteria included previous ipsilateral fracture or surgery, malignancy and immunosuppression.

Results: There was no significant difference found between groups and there was no correlation found with regards to time of injection prior to surgery and infection. Within the injected group, two patients developed a UTI while one other had a pulmonary embolism. There were zero infections with regards to the hip, and there were no dislocations or revisions. The non-injected group included one patient who developed cholelethiasis, another patient with Norfolk virus and one patient with a superficial infection which was contributed to a dental procedure. There were no dislocations or revisions.

Conclusion: These findings suggest that the administration of intra-articular steroid prior to THA does not increase risk of infection, and therefore our study does not find such an injection to be a contra-indicator.

Edward Peter Abraham Neil Manson

Purpose: Adjacent Segment Degeneration (ASD) can occur after spinal fusion, disc degeneration, spinal stenosis, deformity, spondylolisthesis and fracture. The incidence is unknown and its occurence difficult to predict. Further major surgery is required to correct the clinical problem that exists although not all cases of ASD are symptomatic. The primary purpose of this study was to identify the incidence of ASD after multilevel (> /= 3 level) thoracolumbar fusions for degenerative disorders at a minimum 5 year followup. Risk factors for ASD were to be determined.

Method: 405 spinal fusions of three levels or greater, performed between 1988 and 2001, minimum five year followup were assessed for ASD. Radiographic data was available from a prospective data bank. The radiological incidence of ASD was distinguished from those that were clinically significant as determined by Oswestry Disability Index, back and leg pain visual analog scales.

Results: The incidence of ASD after extended spinal fusions overall was 28%, based on radiological evaluation. There was an 18% incidence of clinically significant ASD. 10% of the entire group required surgery to address ASD. The incidence varied according to the location of the fusion, number of levels, age and pre-existing disc degeneration and/or deformity at the end vertebrae. Overall it was difficult to predict risk factors but trends were noted. Long fusion (> /= 3 levels) have a significantly high risk of ASD by five years after the index operation. Adjacent level degenerative disc disease and spinal stenosis were the most common type of ASD.

Conclusion: The incidence of ASD by five years post spine fusion of three or more levels is 28% in over 405 cases. 10% of these cases needed further surgery. ASD is a clinically significant entity that deserves further study to aid in its prevention.

Winston Kim Don S. Garbuz Youxin Hu Ke Duan Bas A. Masri Wang Rizhi Clive P. Duncan

Purpose: Porous tantalum has been shown to be very effective in achieving bone ingrowth. However, in some circumstances, bone quality or quantity is insufficient to allow adequate bone ingrowth. We hypothesized that the addition of alendronate to porous tantalum would enhance the ability of porous tantalum to achieve bone ingrowth in these challenging situations, such as when a gap exists between the implant and bone. We evaluated the effect of alendronate coated porous tantalum on new bone formation in an animal model incorporating a gap between implant and bone.

Method: Thirty-six cylindrical porous tantalum implants were bilaterally implanted into the distal femur of 18 rabbits for 4 weeks. There were 3 groups of implants inserted; a control group of porous tantalum with no coatings, porous tantalum with micro-porous calcium phosphate coating, and porous tantalum coated with micro-porous calcium phosphate and alendronate. Subcutaneous fluorescent labeling was used to track new bone formation. Bone formation was analyzed by backscattered electron microscopy and fluorescent microscopy on undecalcified samples.

Results: The relative increase in mean volume of gap filling, bone ingrowth and total bone formation was 143% (p< 0.001), 259% (p< 0.001) and 193% (p< 0.001) respectively in the alendronate coated porous tantalum compared with the uncoated porous tantalum controls. The relative increase in the percentage of new bone-implant contact length was increased by 804% on average in the alendronate coated porous tantalum compared with the uncoated tantalum controls.

Conclusion: This study demonstrated the significant enhancement of bone-implant gap filling and bone ingrowth which can be achieved by coating porous tantalum with alendronate. It is proposed that, when faced with the clinical problem of revision joint replacement in the face of bone loss (at the hip, knee or elsewhere), the addition of an alendronate-delivery surface coating would enhance biological fixation of the implant and promote the healing of bone defects.

D. Joshua Mayich Mark Harrison Sandip SenGupta

Purpose: Intraoperative frozen section analysis in which the number of cells per high powered field (CPHF) are used to predict the presence or absence of infection has been found to be a very useful test in the setting of revision total joint arthroplasty. The purpose of this retrospective review was to determine the usefulness of this same test at the time of implantation of a total hip arthroplasty (THA) following the failure of hip fracture fixation.

Method: A retrospective review from 1999 – 2007 of twenty-two consecutive patients who had THA performed as a result of failed hip fracture fixation. The mean age of patients was seventy-two years. The number of CPHF was correlated with the results of intraoperative cultures, and other pre-operative and post-operative parameters. The mean duration of follow-up was 14 months.

Results: Two patients had a culture-proven infection (Staphylococcus aureus in one patient, and staphylococcus epidermidis and propionibacterium acnes in the other.) Both of these patients had a positive test for infection based on the frozen section having greater than ten CPHF by the pathologist. (100% agreement) Four out of the six specimens that were graded as 10 CPHF by the pathologist had negative intra-operative cultures (33% agreement). With the CPHF limit set at 10 CPHF, the sensitivity of frozen section analysis in this clinical setting was 100%, while the specificity was 19%. The positive predictive value was calculated to be 33%, and the negative predictive value was 100%. With the cutoff of 5 CPHF or greater, the sensitivity of 100% and a specificity of 52% as well as a positive predictive value of 17% and a negative predictive value of 100%.

Conclusion: Although the results are preliminary, and further study is warranted, it seems that CPHF is a useful test to rule out the presence of infection when revising failed fracture fixation to Total Hip Replacement..

Alison Klika Wael K. Barsoum Ho H. Lee Viktor Krebs Boris Bershadsky

Purpose: There is a paucity of literature describing clinical outcomes following hip arthroscopy. Variables associated with short or prolonged recovery are undefined. This presents a challenge to surgeons in preoperatively communicating with patients about expectations after surgery. The goals of this study are to identify predictors of recovery and to develop models which will facilitate the proper counseling of patients prior to hip arthroscopy. In this study, we define a normal recovery after hip arthroscopy, determine the predictive values of preoperative and intraoperative variables for recovery and for progression to total hip arthroplasty (THA) after hip arthroscopy.

Method: A retrospective review of 216 individuals treated with hip arthroscopy at a tertiary medical center was conducted by a single reviewer. Univariate analysis was used to identify independent variables that correlated with prolonged or short recovery following hip arthroscopy and also on variables correlated with progression to THA. Binary logistic regression analysis was used to develop and test multivariate models for predicting prolonged recovery and progression to THA.

Results: Univariate analyses revealed multiple variables (spanning demographics, past medical history, radiographic findings, physical examination findings, and intraoperative findings) which were significantly (p≤0.05) correlated with prolonged recovery (13 significant predictors) and also with progression to THA (14 significant predictors). A multivariate predictive algorithm was generated using 5 significant predictors of prolonged recovery, which included Workman’s compensation involvement, female gender, use of pain medications, presence of a limp, and presence of a lateral labral tear. This algorithm was tested successfully using an independent sample of 25 individuals. Three multivariate predictors of progression to THA after hip arthroscopy were identified, including radiographic presence of arthritis, female gender and the presence of grade 4 chondral lesions, and a predictive algorithm was generated.

Conclusion: We generated and initially validated a multivariate algorithm to predict prolonged recovery following hip arthroscopy. If validated in larger sample, this model may allow a surgeon to appropriately counsel patients regarding expectations for recovery after hip arthroscopy.

Eric Bohm

Purpose: This prospective survey was undertaken to document the impact of total hip replacement surgery (THA) on patients’ ability to return to work and fulfill their occupational duties.

Method: Patients under the age of 65 awaiting elective THA were asked to complete a validated self-administered questionnaire pre-operatively and 1 year following surgery.

Results: Sixty of 84 patients who completed the pre-operative questionnaire considered themselves to be in the workforce. Twelve of these 60 (20%) were off work due to their hip condition while waiting for surgery, while the remaining 48 were employed. At 1 year post-surgery, 3 patients were lost to follow-up, and 3 had removed themselves from the waitlist and not undergone surgery. Only 1 of 44 (2%) of patients working pre-operatively did not return to work following surgery because of their hip condition. Two of 10 (20%) patients off work prior to surgery because of their hip returned to work following surgery, 5 (50%) indicated that they did not return to work because of their hip, and the remaining 3 (30%) patients did not resume working due to factors other than their hip. Patients who returned to work following surgery demonstrated increases in measures of their ability to meet work place physical, productivity, and income.

Conclusion: Twenty percent of patients waiting for THA stop working prior to surgery because of their hip condition; half of these patients still report being unable to work following surgery. However, the vast majority of THA patients working pre-operatively report being able to return to work following surgery, and these patients demonstrate increases in their ability to meet workplace physical demands, productivity, and income. These findings underscore the importance of undertaking surgery in a timely fashion in order to prevent further deterioration in function.

Michael J. Dunbar Allan Hennigar Margaret Miedzyblocki Freeman Lockhart Michael Gross J. David Amirault Gerald Reardon

Purpose: To meet the increasing demand for arthroplasty in Canada healthcare providers are investigating efficiency improvements to maximize utilization of limited surgical resources. One target is routine annual arthroplasty follow-up for which there are no established guidelines. A previous study by the authors revealed that 52% of arthroplasty patients could be followed with standardized questionnaires and x-rays resulting in a 30% savings to the healthcare system. In this study we report the patient time, travel and financial burdens for annual follow-up at a tertiary care centre versus a hypothetical model using standardized assessment at community hospitals and a web-enabled PACS.

Method: A consecutive sample survey of elective THA and TKA patients (n=158; 99 females; 94 THA; 64 TKA; mean age=69 years) who were at least twelve months postoperative. Patient’s address, work status, mode of travel and times required for travel, physician consult, x-ray, and clinic wait were recorded. A web-based mapping application was used to determine distances from patients’ homes to the tertiary care centre and nearest community hospital. Financial burden was calculated using Statistics Canada figures for average Canadian wage and private vehicle travel costs.

Results: Sixteen patients were working at the time of the study and 149 travelled in a private vehicle. For the tertiary care centre: round-trip distance was 168 km, total time burden was 194 minutes (travel=129 minutes, clinic wait=54 minutes, time with physician=6 minutes, x-ray=5 minutes), and total financial burden per patient was $58. For the community hospital: round-trip distance was 19 km, total time burden was 39 minutes (travel=14 minutes, clinic wait=20 minutes, x-ray=5 minutes), and total financial burden was $7.

Conclusion: Utilizing community hospital resources for arthroplasty follow-up could reduce patients’ travel by 89%, financial burden by 88%, and time burden by 81%. This approach has the potential to enable the focusing of arthroplasty clinic follow-up resources only on patients reporting problems or with symptomatic x-rays thus freeing up surgeon time for surgeries. There are also the broader societal implications of reducing ‘health miles’ and the resulting carbon dioxide emissions related to health care delivery by leveraging new technologies to move information rather than people.

Richard J. Friedman Bengt I. Eriksson Lars C. Borris Sylvia Haas Menno V. Huisman Ajay K. Kakkar Tiemo J. Bandel Eva Muehlhofer Frank Misselwitz William Geerts

Purpose: Thromboprophylaxis is recommended for at least 10 days and up to 35 days following total hip replacement (THR). Rivaroxaban is an oral, direct Factor Xa inhibitor in advanced clinical development that showed promise in early clinical trials. The purpose of this randomized, double-blind, double-dummy, phase III study was to compare the efficacy and safety of oral rivaroxaban with subcutaneous enoxaparin for 5 weeks, to prevent venous thromboembolism (VTE) in patients undergoing primary THR.

Method: Patients received 10 mg rivaroxaban orally 6–8 hours after surgery and once daily thereafter, or 40 mg enoxaparin subcutaneously the evening before surgery (restarting 6–8 hours after surgery), and continued once daily. Thromboprophylaxis was administered for 35±4 days, and mandatory, bilateral venography was conducted the next day. The primary efficacy endpoint was the composite of any deep vein thrombosis (DVT), non-fatal pulmonary embolism (PE), and all-cause mortality. The primary efficacy analysis was a test for non-inferiority, followed by a test for superiority. Safety endpoints included major and non-major bleeding during the active treatment period.

Results: A total of 4541 patients were randomized to receive rivaroxaban or enoxaparin. Rivaroxaban significantly reduced the incidence of the composite of DVT, PE, and all-cause mortality compared with enoxaparin (1.1% vs 3.7%, respectively; p< 0.001; relative risk reduction [RRR] 70%). Rivaroxaban also significantly reduced the incidence of major VTE compared with enoxaparin (0.2% vs 2.0%, respectively; p< 0.001; RRR 88%). There were no significant differences in the incidence of major bleeding (0.3% vs 0.1%; p=0.178) or non-major bleeding (5.8% vs 5.8%; p=1.000) between rivaroxaban and enoxaparin, respectively. There was no evidence of cardiac or liver safety issues.

Conclusion: Oral, once-daily rivaroxaban was significantly more effective than subcutaneous, once-daily enoxaparin for extended thromboprophylaxis following THR. Rivaroxaban was not associated with an increased risk of bleeding and had a similar safety profile to enoxaparin. This trial demonstrated the efficacy and safety of a fixed, unmonitored dose of an oral, direct Factor Xa inhibitor – rivaroxaban – for extended thromboprophylaxis after THR.

Ajay K Kakkar James Muntz Sylvia Haas Benjamin Brenner Ola E Dahl Bengt I Eriksson Patrick Mouret Tiemo J Bandel Andrea G Soglian

Purpose: Venous thromboembolism (VTE) is a common, potentially fatal complication of major orthopaedic surgery. Pharmacologic thromboprophylaxis is recommended following total hip replacement (THR) for a minimum of 10 days, and up to 35 days. However, its extended use is not accepted universally – an effective, safe and convenient, oral anticoagulant would improve implementation of these recommendations. This study was conducted to compare short-term thromboprophylaxis with enoxaparin and extended thromboprophylaxis with the novel, oral, direct Factor Xa inhibitor rivaroxaban after THR. This was the largest, prospective, randomized clinical trial conducted to date for the evaluation of the risk/benefit of extended duration thromboprophylaxis.

Method: In this global, double-blind trial, 2509 patients undergoing THR were randomized to receive either subcutaneous enoxaparin 40 mg once daily (od), beginning the evening before surgery and continued for 10–14 days, followed by placebo until day 35±4 (short-term prophylaxis); or oral rivaroxaban 10 mg od beginning 6–8 hours after surgery and continuing for 35±4 days (extended prophylaxis). Mandatory, bilateral venography was conducted on day 36±4. The primary efficacy endpoint was the composite of any deep vein thrombosis (DVT), non-fatal pulmonary embolism (PE), and all-cause mortality. The main secondary efficacy endpoint was major VTE; the composite of proximal DVT, non-fatal PE, and VTE-related death. Safety endpoints included the incidence of major and non-major bleeding.

Results: Extended thromboprophylaxis with rivaroxaban significantly reduced the incidence of both the primary efficacy endpoint (2.0% versus 9.3%, respectively; p< 0.001; relative risk reduction [RRR] 79%) and major VTE (0.6% versus 5.1%, respectively; p< 0.001; RRR 88%), compared with short-term enoxaparin. The incidence of major bleeding was 0.1% in patients receiving either extended or short-term thromboprophylaxis. Non-major bleeding was reported in 6.5% of patients receiving extended prophylaxis with rivaroxaban and 5.5% of those receiving short-term enoxaparin.

Conclusion: Extended duration thromboprophylaxis with rivaroxaban was significantly more effective than short-term enoxaparin for the prevention of VTE in patients undergoing THR. Both regimens were associated with a similar incidence of bleeding. Extended thromboprophylaxis provides substantial benefits for patients undergoing THR and rivaroxaban provides a safe and effective option for this strategy.

Justin de Beer Dale Williams Danielle Petruccelli Mitchell J. Winemaker

Purpose: Medical research has classically been based on the male model, this is no different in the design of arthroplasty implants. Focus has recently shifted to gender-specific implant design but little evidence exists in the literature as to gender specific outcomes. We hypothesized that outcomes in arthroplasty patients are affected by gender.

Method: Patients were retrospectively identified from a prospectively collected database of total joint arthroplasties performed at one center. Six surgeons performed 1123 primary unilateral cemented TKA’s, and 989 primary unilateral cementless THA’s over a period of seven years. General demographic data was collected along with preoperative and 1-year clinical outcomes including the Knee Society (KSS)/Harris Hip Scores (HHS) and Oxford Knee/Hip scores. These were compared to determine differences, if any, between genders using independent samples t-test and chi-square test for proportions.

Results: The TKA sample was comprised of 540 (55%) females and 449 (45%) males. The THA sample included 744 (66%) females and 379 (34%) males. In the TKA group, females were significantly younger, had higher BMI and differing rates of comorbidities and complications. Female KSS, Oxford and flexion outcomes were significantly inferior to male scores pre-operatively and at 1-year follow-up. Significantly more females reported higher pain scores than males from pre-op to one year. Interestingly, females showed significantly more improvement from pre-op to one year in both scores. In the THR group there were varying rates of complications and comorbidities by gender. Females did significantly worse in the HHS and Oxford hip score from pre-op until one year when results equalized. Similarly pain scores were higher for females preop and at 6 weeks but became equivalent thereafter. Females showed significantly greater improvement from pre-op to 1 year for both outcome scores.

Conclusion: As reported in the literature, results of this study indicate that women choose arthroplasty at a later stage of disease than men do, presenting with inferior functional status. The effect of waiting seems most marked in the knee arthroplasty population with inferior outcomes and pain relief persisting out to one year. Surgeons must counsel females differently about expectations and recovery in joint arthroplasty.

Andrea L. Bowers Jaimo Ahn Jonathan Wanderer Mary Ann E. Keenan

Purpose: Although more than half of all medical graduates are now female, orthopaedics has experienced the least growth of all primary surgical fields in attracting female residency candidates. Our purpose was to identify ways to enhance female interest in orthopaedic surgery as a career.

Method: The effect of exposure on interest in orthopaedics was studied prospectively for two years. Enrollment data regarding student demographics, interest, and exposure to orthopaedic, general, or other surgical subspecialties was obtained from two medical schools. At 6 month intervals, students were offered electronically-based orthopaedic literature, elective lectures, and were resurveyed for exposure and interest level. Univariate analysis was performed between demographics, background, exposure variables and interest levels. Change in exposure was further analyzed against change in interest with a multivariate logistic regression model constructed using significant associations along with gender.

Results: 274 females and 73 male controls enrolled. Baseline increased interest in orthopaedics was correlated in a multivariate model with personal experiences as musculoskeletal patient and/or researcher, among others (p< 0.05). Interim enhanced exposure to orthopaedic web materials was significantly associated with increased interest, intent to enroll in an elective, and intent to apply for orthopaedics or sports medicine. Interestingly, no associations with other surgical specialties were found, and gender was not a significant independent determinant of interest and intent in this model.

Conclusion: This study demonstrates that interest among female medical students can be significantly increased by enhancing exposure to orthopaedic subject matter during medical school. Early exposure may prove a critical tool in recruiting more women into orthopaedic surgery, which will be necessary to meet the anticipated demands of the growing orthopaedic patient population.

Anil Ranawat Serena S. Hu William Levine M. Niederle Christopher Harner

Purpose: Currently, approximately 90% of the 620 graduating orthopaedic residents are planning on entering a post-graduate fellowship. Since January of 2005, two of the largest orthopaedic fellowship match programs, Sports Medicine and Spine Surgery, were dissolved by the NRMP due to gradual decline and reduced participation leaving approximately 70% of applicants in a non-match, decentralized system.

Method: An on-line survey was designed by orthopaedic leadership of the AOA with the help of two Harvard business school “match” economists. The survey was administered to PGY-4 orthopaedic residents participating in the AOA Resident Leadership Forum (RLF) of 2007. This data was used as the cornerstone of the RLF for 2007, where the residents deliberated the results of the survey and formulated a brief recommendation list. The survey responses were then tabulated electronically and subjected to market analysis.

Results: Sixty-five out of 112 (58%) RLF Residents answered the on-line survey, while 93 (83%) answered audience response questions at the RLF. Thirty percent of residents (19/64) did not have enough time and exposure in their residency to decide which subspecialty to enter. They felt the ideal interview period should be held from January through March of the PGY-4 year. Over 50% of residents felt pressure to accept early offers, had to accept an offer before finishing interviewing or accepted their first offer. Sixty-eight percent (43/64) had to respond to an offer in less than one week. Seventy-six percent (31/47) felt they were given inadequate time to accept or reject offers. Thirty-six percent (17/47) asked for more time to think about an offer. Over 50% (33/65) accepted their first offer and 8% (5/47) had an offer withdrawn because they did not give a response within a designated time frame (exploded offer). Residents cancelled a mean of 2.7 interviews per resident (range 0–9). Eighty-percent (50/64) thought a match would be better than the current system, if most programs would adhere to it. Approximately 47% (41/88) of the residents favored a more centralized process involving all orthopedic surgery fellows, while 35% (31/88) favored a subspecialty based system.

Conclusion: The RLF deliberations can be summarized as follows:

The current fellowship hiring process is decentralized, poorly functioning, unraveled and generally unfair. It creates anxiety for residents, residency directors, and fellowship directors alike. Residents are facing exploding offers, limited exposure to fellowship programs and, ultimately, an unraveling hiring market.

Residents are in favor of changing the current decentralized process into either a more centralized clearing-house system or subspecialty-based match approach.

In either system, accountability for both residents and fellowship directors is critical.

Both the AOA and AAOS should devote resources to improve the fellowship hiring process.

Terence Gioe Kate Pico Ann E. Van Heest Penny J. Sinner

Purpose: Despite increasing numbers of women entering surgical fields, orthopaedic surgery residency continues to have the lowest percentage of women (11%) of all primary surgical specialties. In an effort to examine prevailing attitudes, we compared the performance of male and female orthopaedic residents using a variety of measures. We hypothesized that the performance of men and women would not differ significantly.

Method: We prospectively gathered data on 81 residents (67 male, 14 female) with graduation years of 1999–2010. Six males and one female dropped out of the program during their training, leaving a group of 74 residents (61 male, 13 female) with data available for analysis. Residents were compared on the basis of their Orthopaedic In-Training Exam (OITE) scores, American Board of Orthopaedic Surgery (ABOS) results, and a comprehensive eight category electronic faculty evaluation measure (E*ValueTM) that rates resident performance in every category on each rotation on a 1–5 scale. Practice profile data was gathered through a survey which looked at fellowship training and current practice patterns.

Results: Males and females had no statistically significant differences in their E*ValueTM scores in any of the eight categories measured (medical knowledge, patient care, behaviors, technical, communication, practice-based, systems-based, overall competence). Males and females had no significant difference in their mean OITE scores for year 2 and year 3 of residency; however, men had higher mean scores at year 4 (66.9 vs. 47.0), year 5 (66.8 vs. 45.8) and overall (61.7 vs. 46.5, p < 0.001). All resident graduates that had taken ABOS Parts 1 had passed; however, the percentage of men that took more than one attempt to pass Part 1 was significantly lower statistically than women (7% vs. 43%). No difference was seen in Part 2 pass attempts. For residents that had matched in our program, 9% of males and 7% of females have dropped out due to lifestyle issues (NSD).

Conclusion: In our program, male and female residents were seen as equally competent physicians as graded by comprehensive faculty evaluations. However, men outperformed women on both OITE measures and ABOS Part 1 measures. Further study is needed to explain these differences.

François Cabana Gilles Boire Michèle Beaulieu Dominique Lambert Julie Robindaine Line Larrivée Noémie Poirier

Purpose: Only 20% of women presenting with fragility fracture are subsequently investigated for Osteoporosis (OP). Blurred lines of responsibility between the orthopedic surgeons (OS) and the general practitioners may partly explain this situation. OPTIMUS is a 3 year health management program, lead by an OS and a rheumatologist, whose objective is to improve the rate of initiation of and persistence on treatment of OP in patients sustaining a fragility fracture visiting an OS at the Centre hospitalier universitaire de Sherbrooke.

Method: All outpatients aged 50 years and older in which a fragility fracture is suspected by the OS are informed by a nurse practitioner about the OPTIMUS program. The first 200 patients seen at the Hôtel-Dieu site of the CHUS represent the control group. Inpatients with hip fragility fracture are evaluated by a rheumatologist. After signed consent, outpatient participants are randomized to one out of two intervention groups: The Minimal Intervention group includes nurse counseling and written general information transmitted to both patient and treating physician. Same information is given in the Intensive Intervention group. Blood tests and osteodensitometry are also performed and results transmitted to the treating physician along with personalized guidelines for treatment of the patient’s OP. In both interventions, patients are reached by phone at fixed intervals. Additional rounds of intervention are repeated as needed to increase the rates and persistence of appropriate treatment.

Results: Over the first 6 months, the OS team identified 300 patients, 30% of which suffered from hip fracture. Acceptance rates to OPTIMUS management program were close to 95% with direct contact as compared to 50% with delayed phone contact. 5% of outpatients could not name a treating physician and thus had to be seen in rheumatology. The results during the first 18 months of the project will assess the feasibility of OPTIMUS’ interventions.

Conclusion: There is a substantial care gap in the management of OP, despite the availability of diagnostic modalities and effective treatment. Involving orthopedic surgeons as key leaders of a multidisciplinary team implementing a systematic approach to identify patient with OP should help to close this care gap.

John C. Richmond Maureen Spencer Susan M. Davidson

Purpose: Asymptomatic colonization with methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staph. aureus (MSSA) has been described as a risk factor for subsequent surgical site infection. Colonization of nares, either present at admission to the hospital or acquired during hospitalization, increases the risk for infection. Identifying Staph. aureus colonization in the presurgical screening process is important in reducing subsequent surgical site infection. We performed anterior nares surveillance screens of 6551 inpatient surgeries using polymerase chain reaction (PCR) assay. This rapid technology provided results in less than 24 hrs and a decolonization protocol was administered.

Method: Patients admitted for orthopedic surgery were screened in the prescreening unit. The treatment intervention for MRSA and MSSA patients was 5-day application of intranasal mupirocin 2% applied twice daily. In addition, MRSA positive patients were instructed to bathe with chlorhexidine 2% for 5 days and were rescreened prior to surgery. Contact precautions were implemented if the second screen was positive for MRSA. All MRSA positives received vancomycin for surgical prophylaxis.

Results: From July 17, 2006 through August 31, 2007, 6551 patients were screened; 1471 (22%) were MSSA positive and 291 (4%) were MRSA positive. Repeat nasal screens were obtained from MRSA patients prior to surgery and revealed 86% eradication. In the cohort of positive screens, there were 3 MSSA infections (0.2%) and 3 MRSA infections (1.0%). In the 4789 negative screens there were 7 infections (1 MRSA and 6 MSSA). The surgical site infection rate in the screened patients was 0.2%. In an equivalent group of unscreened patients from the prior year, the infection rate had been 0.4%.

Conclusion: We have successfully implemented an MRSA and MSSA eradication program for all inpatient surgeries during the prescreening process. It has allowed for early identification of patients colonized with MRSA and MSSA, decolonization treatment, and appropriate surgical prophylaxis for MRSA. Since implementation we have documented a significant reduction in infection rates due to MRSA and MSSA. A multidisciplinary approach with strong administrative support and consistent communication was vital to the implementation of the program.

Louis Bessette Jacques P. Brown Sonia Jean K. Shawn Davison Michèle Beaulieu Mirela Baranci Jennifer Bessant Louis-Georges Ste-Marie

Purpose: Recognizing Osteoporosis and Its Consequences in Québec revealed that 73% of women 50y and over are not provided anti-fracture therapy following fragility fracture. This study’s objectives were to determine predictors of osteoporosis (OP) diagnosis (DX) and treatment (TX) 6 to 8 months after fragility fracture.

Method: At phase 1, women were recruited at cast or out-patient clinics within 16 weeks post-fracture. Consenting patients answered a short questionnaire classifying them as experiencing a fragility or traumatic fracture; no reference to the association between fracture and OP was made and no investigation or intervention was proposed. At phase 2, 6–8 months post-fracture, the women completed a questionnaire on demographic features, clinical characteristics and risk factors for OP. The DX (informed of OP and/or BMD measurement with diagnosis of OP) and TX (bisphosphonates, raloxifene, nasal calcitonin or teriparatide) rates of OP were determined via this questionnaire. This analysis included only women with a fragility fracture who were not receiving OP TX at phase 1.

Results: Of the 1273 women completing phase 1, 1001 (79%) sustained a fragility fracture; 818 were untreated at phase 1 and completed the phase 2 questionnaire. Overall, 79% of these participants had not received a DX of osteoporosis or were without OP TX at phase 2. The highest rate of DX and TX of OP occurred 0–5 months post-fracture and decreased considerably thereafter. In multivariate analyses, the results of BMD tests before or after the fracture event (p< 0.0001) and mobility problems (p=0.03) were the only variables that influenced the DX of OP. BMD test results were the strongest predictor (p< 0.0001) of TX followed by the fracture site (hip, femur and pelvis; p=0.015) and administration of vitamin D supplements at the time of fracture (p=0.035). No other risk factors for OP significantly influenced the DX or TX rate. No demographic or clinical features or OP risk factors were significantly associated with the decision to refer women for BMD testing post-fracture.

Conclusion: Although fragility fracture represents a greater risk of future fragility fracture than low BMD, physicians based their decision to treat on BMD and not the clinical event (fragility fracture).

Michael J. Prayson Alison L. Manternach Brian Imbrogno Paul R. Sensiba David O. Griffith Indresh Venkatarayappa

Purpose: Surgical staples are routine in closure of surgical incisions. Staples allow for expeditious closure and removal compared to suture materials. Concern exists, however, in obtaining an MRI scan when staples are present. The study analyzes common issues related to MRI scanning in the presence of surgical staples.

Method: Thirty pig feet had one-inch surgical incisions made and repaired with five standard stainless steel surgical staples. Two parameters were analyzed: temperature change on the skin surface and staples displacement. Once placed, each skin staple position was marked for later referencing. A surface temperature laser device (Fluke 62 Mini) recorded pre-scan skin surface temperature. A 35-minute MRI scan was performed using a 1.5 Tesla magnet with a standard knee coil for each of the pig feet in an MRI suite at ambient room temperature. Immediately afterwards, the skin surface temperature was recorded and distance measurements were made in relation to the pen markings. A paired T-test was utilized to analyze the pre and post-scan data.

Results: The mean temperature before the scans was 16.45 degrees Celsius with a standard deviation of 0.7 degrees. The median pre-scan temperature was 16.4 degrees. The minimum temperature was 14.6 degrees and maximum was 18.2 degrees. After scanning, the mean temperature was 16.02 degrees Celsius with a standard deviation of 0.63 degrees. The median post-scan temperature was 15.8 degrees. The minimum temperature was 15.0 and maximum temperature 17.6 degrees. The skin surface temperature showed a significant drop of 0.43 degrees Celsius (p=0.001). No change was recorded in staple position for any of the thirty pig feet pre-scan compared to post-scan.

Conclusion: Occasionally, patients require MRI scans after having surgery where staples have been used to repair the incision(s). Concern exists over heat generation or movement of the staples during the magnetic process. This study demonstrated no recordable increase in skin surface temperature or displacement of staple position after a standard extremity MRI scan. Based on the findings of this study, MRI scanning in the presence of surgical staples appears safe.

Mohit Bhandari Simon Chan

Purpose: The CONSORT statement for the reporting of randomized controlled trials (RCTs) has limitations in its applicability to non-pharmacological trials. In response, the CLEAR NPT, a checklist that provides guidelines for the reporting of RCTs in surgery, has been developed. We aimed to

apply the CLEAR NPT to orthopaedic RCTs across multiple journals from 2004–2005, and

survey authors when items in the CLEAR NPT were not reported to determine if they were actually conducted.

We hypothesized that “lack of reporting” did not necessarily correlate with “not being conducted”.

Method: We searched for relevant orthopaedic RCTs across eight journals (four Orthopaedic, four General Medicine) in the period from January 2004 through December 2005. We applied the CLEAR NPT to all eligible studies. We contacted authors to determine what methodological safeguards were actually used, especially when details remained unclear from the publication.

Results: We included eighty-seven RCTs from eightyfive scientific reports. In assessing the RCTs with the CLEAR NPT, seventy-three (84%) studies had unclear reporting of allocation concealment. Only seventeen (20%) studies made mention of operator skill or experience. Participant, ward staff, rehabilitation staff, clinical outcome assessor and non-clinical outcome assessor blinding were found to be unclear in forty-eight (55%), sixty-three (72%), sixty-four (74%), forty (46%) and thirty-three (38%) studies respectively. Authors from forty-three RCTs responded to our survey. In direct contact, authors reported adequate allocation concealment 41% (95% CI = 25–58%) of the time when this was unclear from the RCT report. 70% of authors acknowledged that they had set objective measures such as minimum case criteria and/or comparison to good clinical outcomes. Authors specified that they had blinded relevant groups 28–40% of the time, despite unclear reporting in the publications.

Conclusion: The quality of reporting in the orthopaedic literature was highly variable. Readers should not assume that bias reducing safeguards not reported in an RCT did not occur. Our study reinforces the need for a tool like the CLEAR NPT to assess the methodology of surgical trials.

Michael J. Prayson Ronald J. Markert Paul G. Peters Richard T. Laughlin Alison L. Manternach Kyle L. Randall

Purpose: Surgical site infection remains a common concern in orthopaedic surgery. A multitude of factors contribute to colonization of the operative site, not all of which are controllable. This study investigates the time-dependent contamination of sterile C-arm covers as a potentially modifiable risk factor during routine fracture surgery.

Method: A consecutive fracture case study was performed from the two senior authors’ orthopaedic practices. Cultures were obtained from the top and side of the image intensifier cover after initial draping and every 20 minutes until the end of the operation. Survival time analysis was performed to evaluate the median time to first contamination.

Results: Twenty-five cases were enrolled with a mean operative time of 91.8 ± 42.9 minutes and an average people/hour/case of 9.6 ± 1.5. Time to contamination is correlated with person hours per case at 0.52 (p=0.07). The median survival time was 20 minutes (95% CI =12 to 68 minutes). There was 17% contamination upon initial draping, 50% at 20 minute, 57% at 40 minutes, 73% at 60 minutes and 80% by 80 minutes. Of the 30 cases, only 5 did not become contaminated during the surgery. The bacteria detected were Staphylococcus (59%), Corynebacterium (31%), Micrococcus (7%), and other (3%). There were no post-operative wound infections that required medical treatment.

Conclusion: A rapid and significant rate of contamination for C-arm drapes during orthopaedic fracture surgery was recorded. Based on these findings, the surgeon should not touch the C-arm cover to manipulate the machine. If contact with the C-arm cover is necessary, then a change of gloves is warranted to minimize contamination risk.

Ryan T. Bicknell Christopher Chuinard Pascal Boileau

Purpose: The reverse shoulder arthroplasty (RSA) is becoming increasingly common and the indications expanded. The objective of this study is to report the indications and results of RSA in a large multicenter study.

Method: A retrospective, multicenter study was conducted including all RSA implanted between 1992 and 2002 in five centers in France. Of 457 patients involved in this study, 243 patients (53%) had cuff pathology: 149 had cuff tear arthropathy, 48 had massive cuff tears, and 45 had failed cuff surgery. Ninety-nine (22%) had revision of a previous arthroplasty. Sixty (13%) had fracture-related problems. Twenty-six (6%) had osteoarthritis and two percent each had rheumatoid arthritis, tumors or other conditions. Three hundred and eighty-nine (85%) shoulders were available for review at a mean follow-up of 44 months (range, 24–142). The average age at review was 76 years (range, 22–92).

Results: Overall, significant improvement was noted in Constant scores for pain (3.5 to 12.1), activity (5.8 to 15.1), mobility (12.1 to 24.5) and strength (1.3 to 6.1) (p< 0.0001). Active elevation improved (p< 0.0001), but active internal and external rotation did not. The results were dependent on the indication. Cuff tear arthropathy had the best results while revision procedures had the worst. Young age, preoperative stiffness, teres minor deficiency, tuberosity non-union and preoperative complaints of pain rather than loss of function tended to be associated with inferior results. The deltopectoral approach tended toward greater active elevation but greater risk of instability. Survivorship to the endpoints of revision and loosening was better for patients with cuff tear pathology than for patients with failed prior hemiarthroplasty. The functional results were noted to deteriorate progressively after six years in the cuff tear pathology group, after five years in the revision hemiarthroplasty group, after three years in the osteoarthritis group, and after one year in the revision total shoulder arthroplasty group.

Conclusion: Overall results of RSA are satisfactory and predictable. Functional results improved with improved active elevation, but no improvement in active internal and external rotation. However, results are dependent on etiology.

Ryan T. Bicknell Frederick Matsen Gilles Walch Laurent Nové-Josserand

Purpose: Reverse shoulder arthroplasty (RSA) is becoming increasingly common for a variety of indications. The most common postoperative complication is instability. The objectives of this study are to describe causes of RSA instability and preventive and treatment recommendations.

Method: All members of the American Shoulder and Elbow Society were asked for cases of RSA instability. We retrospectively reviewed 52 cases in 52 patients, performed by 13 surgeons. The mean age was 67.5 years (range, 36–83). The mean follow-up was 32.7 months (range, 3–43).

Results: The etiology included: cuff tear arthropathy (14 patients); revision arthroplasty (13 patients); fracture sequelae (6 patients); and other (6 patients). Twenty-four patients had previous shoulder surgery. All patients had a deltopectoral approach. Anterior deltoid deficiency was noted in 3 cases. Subscapularis insufficiency was noted in 27 cases. Humeral component dissociation occurred in 2 patients. The instability was: anterior (27 patients); posterior (5 patients); or inferior (3 patients). Instability occurred: in the first 48 hours (10 cases); between 2 to 30 days (13 cases); or after one month (12 cases). Causes of instability included: inadequate soft-tissue tension (23 patients); a large antero-inferior release (22 patients); subscapularis insufficiency (7 patients); hematoma (2 patients); trauma (2 patients), deltoid insufficiency (2 patients); glenosphere malposition (2 patients); acromion fracture (2 patients); and other (4 patients). Initial treatment included: non-operative (6 patients); closed reduction (23 patients); open reduction (3 patients); and revision arthroplasty (11 patients). Final outcomes included: persistent instability (7 patients); humeral revision (19 patients); glenoid revision (one patient); hemiarthroplasty (3 patients); and resection arthroplasty (2 patients).

Conclusion: Main causes of RSA instability include inadequate soft tissue tension, large anteroinferior release and subscapularis insufficiency. Preventive measures include careful patient selection, restoration of humeral length, minimizing anteroinferior releases, maximizing soft-tissue tension, maintaining or restoring subscapularis integrity, immobilization in the case of subscapularis insufficiency and use of a postoperative drain. Treatment recommendations include restoration of humeral length, soft-tissue retensioning and prolonged immobilization.

Ross M. Wilkins William C. Brown Cynthia M. Kelly

Purpose: Difficult nonunions of the humerus are frequently treated with free vascularized bone, usually the fibula, but donor site morbidity from the lower leg can be significant. The lateral border of the scapula is a 7–12 cm tubular length of vascular bone that can be easily transferred to the humerus.

Method: Nineteen established nonunions of the humerus, including mid-shaft (11), proximal (4), distal (3), and a failed shoulder fusion, were treated with a segment of scapula on a vascular pedicle. Patients (13 females, 6 males with average age of 63) had undergone 3 previous surgeries on average in attempts to heal the fracture. The time from injury to procedure averaged 28 months (range, 5–120 months). The surgical team consisted of an orthopedist and a plastic surgeon working simultaneously with the patient in a lateral position. The scapular graft was juxtaposed to the humerus through an axillary tunnel, then rigidly fixed with plate and screws and grafted with a calcium sulfate and bio-assayed demineralized bone matrix product (Allomatrix, Wright Medical Technology, Arlington TN).

Results: All nonunions healed, achieving radiographic evidence of consolidation between 8–24 weeks (average, 13 weeks). One patient with a previously infected non-union had recurrent infection and required further surgery before healing. Another patient fractured through the mid-portion of the healed graft in a fall two years after surgery and was revised to an endoprosthesis. Patient-based Musculoskeletal Tumor Society scores averaged 83% at 41 months (range, 24–66).

Conclusion: Pedicled transfer of the lateral border of scapula with circumflex scapular artery is an excellent choice for treating recalcitrant humeral nonunions. There were no complications at the donor site and all nonunions healed. Advantages of this procedure are:

Surgery time

J. Michael Wiater Laurence Kempton

Purpose: This paper will present the types and rates of complications of an initial consecutive series of 100 reverse total shoulder arthroplasties (TSA).

Method: Since 2004, the initial 100 consecutive reverse TSA were performed by a single US surgeon in 97 patients with an average age of 72 years. A deltopectoral approach was used in all cases. Diagnoses include 49 shoulders with cuff tear arthropathy, 24 with a failed prior shoulder arthroplasty, 23 with an irreparable rotator cuff tear, 2 with a malunion and post-traumatic arthritis, 1 with rheumatoid arthritis, and 1 with osteoarthritis. All patients had painful pseudoparalysis. Average follow-up was 8 months, with 77 patients having a minimum 2-month follow-up. Two patients have expired (unrelated to surgery), and 1 patient has been lost to follow-up.

Results: Of the 100 shoulders, 9 had local perioperative complications (9%) including 2 dislocations requiring 1 open reduction and 1 closed reduction, 2 intraoperative glenoid fractures, 3 resolved mononeuropathies (radial, ulnar, and musculocutaneous), 1 resolving brachial plexopathy, 1 post-op hematoma, and 1 intraoperative broken screw head. Three of the 4 neuropathies occurred in revision arthroplasty shoulders. Six shoulders (6%) had systemic perioperative complications including subacute MI, DVT, PE, and C. difficile colitis. Two patients (2%) have had complications outside the perioperative period including 1 stable acromial fracture at 5 weeks post-op, and 1 patient with a subluxatable shoulder. No infections occurred. Other than the 2 dislocations and the acromial fracture, no radiographic complications, such as dissociation of the components or catastrophic failure of the glenosphere fixation, were observed. Seven shoulders (7%) had Grade 3 scapular notching and none (0%) had Grade 4 notching. The overall complication rate was 18% with rates of 17% vs. 21% in primary vs. revision arthroplasties, respectively (p=0.91). Transient nerve palsies were more frequent in revisions vs. primaries (12.5% vs. 1.3%, p=0.066).

Conclusion: There is an acceptably low rate of complications related to reverse TSA, particularly severe ones requiring reoperation (2%). Overall complication rates are not significantly different between revisions and primaries, but revisions trended towards more transient nerve palsies.

George S. Athwal Kenneth J. Faber James A. Johnson Simon G. Frank Graham J. W. King

Purpose: Unrepairable fractures of the radial head are often treated with radial head arthroplasty. Insertion of a radial head prosthesis that is too thick, or overstuffed, is believed to be a common complication that may result in pain, arthrosis, capitellar wear and decreased elbow range of motion. The purpose of this study was to develop guidelines for determining the appropriate thickness of radial head implants. We hypothesized that

radiographic incongruity of the medial facet of the ulnohumeral joint and that

the macroscopic presence of a gap in the lateral facet of the ulnohumeral joint correlate with radial head overstuffing.

Method: Six human cadaveric upper extremities were used to evaluate the clinical and radiographic effects of overstuffing of a radial head arthroplasty. Each specimen received an anatomic radial head replacement and then underwent overstuffing with +2 mm, +4 mm, +6 mm and +8 mm lengths. Gross lateral ulnohumeral joint spaces were measured, and anteroposterior radiographs were taken of the elbow from which radiographic medial and lateral ulnohumeral joint spaces were measured.

Results: Intraoperative gapping of the lateral ulnohumeral facet was shown to be highly reliable for detecting radial head overstuffing, increasing from a mean of 0.0 mm at standard length to 1.0 mm with 2 mm overstuffing (p < 0.05). Radiographically, the congruity of the lateral ulnohumeral facet was significantly different with 2 mm of overstuffing as compared to the anatomic length (p < 0.05). The congruity of the medial ulnohumeral facet only became significantly different with +6 mm of overstuffing as compared to the anatomic length (p < 0.05).

Conclusion: Radiographic incongruity of the medial facet of the ulnohumeral joint was an unreliable indicator of radial head overstuffing. Radiographic gapping of the lateral ulnohumeral facet demonstrated sufficient sensitivity to diagnose radial head overstuffing when compare to the standard length implant radiographs. Visual gapping of the lateral ulnohumeral facet on the cadaver specimens reliably indicated radial head overstuffing and should be a useful anatomic feature to assess intraoperatively.

George S. Athwal John W. Sperling Robert H. Cofield Damian M. Rispoli

Purpose: Currently, there is little information available on the management and outcome of intra-operative periprosthetic humeral fractures during shoulder arthroplasty. The purpose of this study was to report on the incidence, management, and outcome of intra-operative periprosthetic humeral fractures.

Method: Between 1980 and 2002, forty-six intra-operative periprosthetic humeral fractures occurred during shoulder arthroplasty at our institution. Thirty-six fractures occurred during primary total shoulder arthroplasty, five during primary hemiarthroplasty and four during revision shoulder arthroplasty. Twenty-one fractures involved the greater tuberosity, 16 the humeral shaft, 6 were metaphyseal and 2 fractures involved the greater tuberosity and extended to the humeral shaft. All patients were followed for a minimum of two years (mean, 7.5 years). At final follow-up, the Simple Shoulder Test (SST) and ASES scores were calculated and preoperative, postoperative, and most recent radiographs were examined for fracture healing and implant integrity.

Results: The incidence of intra-operative humerus fractures at our institution was 1.5%. All fractures healed at mean of 13 weeks (range, 6 to 56 weeks). At a mean final follow-up of 90 months (range, 25 to 194 months), the mean forward elevation was 108° and the mean external rotation was 39°. The mean SST was 6 and the mean ASES score was 61. Four patients underwent revision shoulder surgery, two for shoulder instability, one for a massive rotator cuff tear, and one for another periprosthetic humerus fracture that occurred after a fall. Complications included transient nerve injuries in six patients and four fractures displaced postoperatively which were then managed nonoperatively to healing.

Conclusion: The data from this study suggest that although intra-operative fractures have a high rate of healing, there was a significant rate of associated complications including transient nerve injuries and fracture displacement. Patients with intra-operative fractures also appear to have less forward elevation at final follow-up when compared to patients who have not sustained an intra-operative humeral fracture.

Brent Lanting Robert B. Bourne Cecil H. Rorabeck Jeff Guerin Douglas Naudie

Purpose: Unicompartmental knee arthroplasty remains a viable treatment modality for arthrosis confined to the medial compartment of the knee. Few studies have reported survivorship of this procedure into the second decade. The purpose of this study was to report our long-term experience with this procedure at a mean follow-up of fifteen years.

Method: Between 1989 and 2000, 113 medial unicompartmental knee arthroplasties in 84 patients were performed using the Miller-Galante prosthesis. The 84 patients had an average age of 68 years old at the time of surgery; 45 of which were male and 39 female. At a mean of fifteen-year follow-up, 22 patients (25 arthroplasties) had died, and the remaining 62 patients (88 arthroplasties) were reviewed and evaluated. No patient was lost to follow-up.

Results: The mean Knee Society knee and function scores had an improvement from 53 and 48 points pre-operatively to 77 and 90 points respectively at time of most recent evaluation. Twenty unicompartmental knee arthroplasties were revised, at an average of seven years (one to fourteen) following index procedure. The five, ten and fifteen-year rates of survival were 94%, 90%, and 86% respectively with revision to tricompartmental knee arthroplasty as the end point.

Conclusion: The Miller-Galante medial unicompartmental knee arthroplasty provided excellent pain relief and restoration of function in carefully selected patients and demonstrated durable implant survival at fifteen years. Progression of arthrosis is the primary mode of failure.

Christian Veillette Akin Cil Joaquin Sanchez-Sotelo John Sperling Robert Cofield

Purpose: Loosening of the humeral component is rarely a cause for revision shoulder surgery. Most long-term series are not large enough to stratify the many risk factors that might influence the survivorship of humeral component designs. The purpose of this study was to determine long-term survivorship of the Neer and Cofield humeral components and to define the risk factors associated with humeral component removal or revision.

Method: 1584 primary Neer and Cofield shoulder arthroplasties (1423 patients) were performed at our institution from 1984 to 2004. There were 619 men (694 shoulders) and 804 women (890 shoulders), with a mean age at arthroplasty of 65.6 years (range, 16–94 years). Kaplan-Meier survivorship analysis was used to determine the effect of etiology of the disease, gender, age, surgery type (hemi versus total), fixation type (cemented versus noncemented), and the humeral component type (Neer II, Cofield I or II) on the estimated survival free of humeral component revision or removal.

Results: There were 108 revisions and 17 removals of the humeral component. The overall rate of removal or revision of the humeral component was 7.9% with an average followup of 8.1 years. The rates of survivorship free of revision or removal of the humeral component for any reason was 94.8% at 5 years, 92% at 10 years, 86.7% at 15 years and 82.8% at 20 years. Seventy-one of 632 shoulders (11.2%) in patients younger than 65 years required humeral component revision or removal, whereas only 54 of 952 shoulders (5.7%) in patients 65 years and older required humeral component revision or removal (Odds ratio=2.1; 95% confidence interval, 1.5–3, p=0.001). Patients with posttraumatic arthritis had a higher risk of needing revision or removal of the humeral component (Odds ratio=2.1, 95% confidence interval 1.3–3.3) compared to osteoarthritis. Eighty-four of 526 shoulders (16.0%) with metal-back glenoid components required humeral component revision or removal, whereas only 41 of 1058 shoulders (3.9%) with non metal-backed glenoid components required humeral component revision or removal (Odds ratio=4.7; 95% confidence interval, 3.2–7, p=0.001).

Conclusion: Younger age, replacement due to post-traumatic arthritis and presence of a metal-backed glenoid increased the likelihood of humeral component failure. Similar short-term survival can be achieved with Cofield II and Neer II humeral components.

Christian Veillette Akin Cil Joaquin Sanchez-Sotelo Bernard F. Morrey

Purpose: The long-term experience of linked semicon-strained total elbow arthroplasty was investigated as a salvage procedure for patients with distal humerus non-union not amenable to internal fixation.

Method: Ninety-two consecutive total elbow arthroplasties performed for the treatment of a distal humeral nonunion were reviewed at an average follow-up of 6.5 years (range, 0.5 to 20.3 years). There were twenty-two men and sixty-nine women with an average age of sixtyfive years (range, twenty-two to eighty-four years) at the time of elbow replacement. Seventy-six elbows (83 per cent) had undergone prior surgery, with an average of two previous operations (range, one to ten). Five elbows had had at least one prior operation due to infection.

Results: Seventy-nine per cent of the patients had no pain or mild pain at latest follow-up compared with moderate or severe pain in 86 percent prior to surgery. Mean extension was improved from thirty-seven to twenty-two degrees and mean flexion from 106 to 135 degrees. Joint stability was restored in all patients, including nine with a grossly flail elbow. Complications included aseptic loosening in sixteen (four with periprosthetic fractures), component fracture in five, deep infection in five (three with previous infection), and bushing wear in one patient. At most recent follow-up, 85 per cent of the patients were satisfied with their outcome. Survivorship for not requiring removal or revision for any cause was 95.7 per cent at two years, 82.1 per cent at five years, 65.3 per cent at ten and fifteen years. Factors that increased the risk of implant failure were patient age less than sixty-five, two or more prior surgeries, and history of previous infection.

Conclusion: Linked semiconstrained total elbow arthroplasty provides a reliable salvage procedure to provide pain relief and restoration of motion and function in patients with distal humerus nonunion not amenable to internal fixation. Risk factors for failure include younger patients, multiple previous surgeries, and history of infection.

Stephen Lance Anderson Mario R. Taillon Mark Ernst

Purpose: 2 orthopaedic surgeons identified 18 patients who developed glenohumeral chondrolysis following arthroscopic shoulder surgery. The index surgery for all 18 patients occurred over an 18 month period. We sought to find any common factors among the 18 cases.

Method: A retrospective chart review of all 18 patients was performed. We gathered information on patient demographics, type of surgical procedure, nature of shoulder instability, post-operative complications such as infection, the use of radiofrequency energy, the type/number of suture anchors, the use of an IAPPC and the type of local anaesthetic used. We compared pre-operative radiographs and MRI scans to the intra-operative findings from the operative report to confirm that no chondrolysis was present pre-operatively. We examined post-operative radiographs and MRI scans to document the extent of chondrolysis

Results: Of the 18 patients who developed chondrolysis, we had 15 males and 3 females with an average age of 23 years (range 16–39). 17 patients had shoulder instability due to a definitive traumatic event while 1 patient had an atraumatic etiology. No radiofrequency energy was used in any of the cases. No post-operative infections were diagnosed and many had work-ups for infection which included ESR, CRP, bone & gallium/WBC scans. All patients had labral stabilization procedures, 15 anterior (Bankart), 1 posterior, and 2 combinations. All patients received suture anchors, 13 patients had 2 anchors and 5 had 3 anchors. 2 different manufacturer’s suture anchors were used, 10 patients received Smith & Nephew anchors while 8 patients received Linvatec anchors. 10 patients received bioabsorbable anchors and 8 patients received metal anchors. All patients received an IAPPC loaded with 0.5% bupivacaine with epinephrine for post-operative pain control. 15 of the IAPPC’s were considered large with an infusion rate of 5 mL/hr and a fill volume of 275 mL’s. 3 IAPPC’s were considered small with an infusion rate of 2 mL/hr and a fill volume of 100 mL’s.

Conclusion: We suspect a continuous intra-articular infusion of bupivacaine with epinephrine may have contributed to the development of chondrolysis. We caution against the use of IAPPC’s until their safety has been proven.

Xavier Simcock William Macaulay Richard Yoon Peter Chalmers Jeffrey Geller Howard Kiernan

Purpose: Patients undergoing total knee arthroplasty (TKA) often experience a difficult recovery due to severe post-operative pain. Utilizing a multi-modal pain management protocol, a blinded, randomized, placebo-controlled study was designed to evaluate the efficacy of patient selected music on reducing perceived pain.

Method: Using a standardized intra-operative anesthetic protocol and postoperative pain management protocol, consented patients were randomized into either: 1) the interventional Music group (noise-reduction headphones, patient choice/classical music) or the control, Non-Music group (noise-reduction headphones only). Pain scores, aided by the Wong-Baker and Verbal Descriptor scales, were assessed via the Visual Analog Scale (VAS) at baseline and postoperatively at 3, 6, and 24 hours. A paired Student’s t-test was utilized to determine statistical significance, which was set at a p < 0.05.

Results: Thirty subjects were enrolled. At baseline, there were no statistical differences in mean pain between the study (2.29 ± 2.78) and the control (3.34 ± 2.67) groups (p = 0.19). Mean pain scores reported the Music group to have significantly less pain at 3 hours (1.49 ± 1.39 vs. 3.87 ± 3.44, p = 0.01), and at 24 hours (2.41 ± 1.67 vs. 4.03 ± 2.89, p=0.04).

Conclusion: Intraoperative music provides an inexpensive, non-invasive method of lowering perceived postoperative pain for patients undergoing a TKA. The results of this study offer a glimpse into how an alternative therapy or non-pharmacologic method can reduce postoperative pain. A larger-scale, higher powered trial may demonstrate how music could favorably affect secondary outcomes such as patient satisfaction, range of motion, and length of stay.

Vaishnav Rajgopal Robert B. Bourne Richard W. McCalden Steven J. MacDonald Cecil H. Rorabeck

Purpose: The purpose of this study was to determine the clinical and radiographic outcomes at a minimum follow-up of ten years of patients who underwent a total knee arthroplasty with an inset patellar component. The incidence of anterior knee pain and the factors which may contribute to were also studied.

Method: Patients who had genesis I/II TKA with an inset patellar button with a minimum follow-up of 10 years were identified. 448 patients with 521 knees were identified. Patients were excluded if they were deceased, had incomplete data, were unable to be contacted or had a known or impending revision. Those who had revision were included in a Kaplan-Meier survivorship analysis. The included patients, deceased patients and those lost to follow-up were named group1, 2, and 3 respectively. Demographics and Knee society scores(KSS) were studies for all 3 groups. This was to identify any exclusion bias. Presence and severity of anterior knee pain as well as radiographic factors were collected for group 3. Logistic regression analysis was used to identify and variables that influenced the KSS and presence of anterior knee pain. Kaplan-Meier survivorship analysis was performed for patellar revision and tibial/femoral revision endpoints.

Results: 144 patients with 175 TKA were included in this study. They were on average 66 years old, 64% female, had a BMI of 30 and had a diagnosis of OA 92% of the time. Their average f/u was 11.3 years. Groups 2 and 3 had similar demographics but of course a much shorter f/u. Group 1 had a pre-op KSS of 84 a post-op KSS of 151 and a KS change score of 67. Groups 2 and 3 had similar pre-op, post-op and KSS change scores. We found anterior knee pain occurred in 5% of patients with an average severity of 5/10. Linear regression analysis did not identify any variables including radiographic parameters that had an independent influence on KSS or anterior knee pain. Kaplan-Meier survivorship with patellar revision for any reason as an endpoint was 96% at 10 years and 94% at 17 years. 20 patella were known to have had a revision or were undergoing a revision.

Conclusion: We conclude that use of an inset patellar component can give excellent durable results over time with a low rate of anterior knee pain and complications

Riazuddin Mohammed Ashwin Unnithan Kaustubh Durve Manish Bansal Tushar Jimulia Marcus Green Duncan Learmonth

Purpose: Isolated patellofemoral joint (PFJ) osteoarthritis has long been a common observation as an important source of knee pain. Once non-operative treatment modalities have been exhausted, the surgical options available are transposition/elevation of tibial tubercle, drilling, realignment procedures, patellectomy, patellar resurfacing, patellofemoral arthroplasty (PFA) and total knee arthroplasty (TKA). Among these, PFA is an established treatment of isolated PFJ osteoarthritis. We present our multi-surgeon, multi-implant series of patellofemoral joint arthroplasty performed over a 10 year period.

Method: This study was a retrospective review of all PFA performed in the Knee Arthroplasty Unit at our hospital over a ten year period from 1997 to 2006. The unit comprises seven specialist surgeons, each with considerable experience in knee arthroplasty and numerous trainee surgeons. One hundred and one PFA performed in 91 patients were identified from the theatre records. Three different implant models were used: the Lubinus implant (Waldemar Link), the FPV system (Wright Medical) and the Avon system (Stryker Howmedica Osteonics).

Results: 101 arthroplasties in 91 patients were followed up for average period of 48.8 months (6–96 months). Of these, none were lost to follow up. The average age was 57 years with female patients thrice as common as male patients. Concomitant procedures in the form of 23 lateral retinacular release or 6 osteochondral autograft transfer system (OATS) were performed. There were 6 complications with 2 infections and 4 stiff knees. 31 arthroplasties had subsequent procedures including arthroscopic debridement (18), arthroscopic lateral retinacular release (8), tibial tuberosity transfer (3) and manipulation for stiffness (2). A total of 4 arthroplasties underwent revision to total knee arthroplasty, 2 for infection and 2 for progression of tibiofemoral osteoarthritis.

Conclusion: The necessity of revision surgeries in one third of the cases suggests that close follow-up of the patients is needed to address any concerns that can be easily resolved. A majority of the patients in our study had very good outcomes and did not need subsequent procedures in the medium term. Our study reiterates the importance of proper patient selection, surgeon experience and correct surgical technique in successful outcomes from PFA.

Michael R. Lassen Walter Ageno Tiemo J. Bandel Lars C. Borris Jay R. Lieberman Frank Misselwitz Nadia Rosencher Alexander G. G. Turpie

Purpose: Rivaroxaban is a novel, oral, direct Factor Xa inhibitor in advanced clinical development for the prevention and treatment of thromboembolic disorders. RECORD3 was a phase III trial conducted to compare the efficacy and safety of oral rivaroxaban with subcutaneous enoxaparin for the prevention of venous thromboembolism (VTE) in patients undergoing total knee replacement (TKR).

Method: In this randomized, double-blind trial, patients received rivaroxaban 10 mg once daily (od), or enoxaparin 40 mg od. Enoxaparin was initiated the evening before surgery, and rivaroxaban 6–8 hours after surgery; therapy continued for 10–14 days. The primary efficacy outcome was the composite of any deep vein thrombosis (DVT), pulmonary embolism (PE), and all-cause mortality. Secondary efficacy outcomes included major VTE (the composite of proximal DVT, PE, and VTE-related death) and symptomatic VTE. Major bleeding was the primary safety outcome. Other safety outcomes included any on-treatment bleeding and hemorrhagic wound complications (the composite of excessive wound hematoma and surgical-site bleeding).

Results: A total of 2531 patients were randomized; 2459 were eligible for inclusion in the safety population and 1702 for the modified intention-to-treat population. The incidence of the primary efficacy outcome was significantly reduced with rivaroxaban compared with enoxaparin (relative risk reduction 49%, p< 0.001). Major VTE occurred in 1.0% and 2.6% of patients receiving rivaroxaban and enoxaparin, respectively (relative risk reduction 62%, p=0.016). The incidence of symptomatic VTE was significantly lower in the rivaroxaban group than in the enoxaparin group (p=0.005). Major bleeding rates were 0.6% and 0.5% in the rivaroxaban and enoxaparin groups, respectively, and rates of any on-treatment bleeding were 4.9% and 4.8%, respectively. The incidence of hemorrhagic wound complications was 2.1% in the rivaroxaban group and 1.9% in the enoxaparin group.

Conclusion: Rivaroxaban was significantly more effective than enoxaparin for thromboprophylaxis after TKR. Importantly, the incidence of bleeding was low and similar in both groups. This is the first trial to demonstrate the efficacy and safety of a fixed, unmonitored regimen of an oral, direct Factor Xa inhibitor – rivaroxaban – for thromboprophylaxis after TKR.

John Clohisy Michael Dobson Lucian Warth Steve Liu Karen Steger-May John Callaghan

Purpose: Femoroacetabular impingement (FAI) is a precursor to osteoarthritis (OA) of the hip. To investigate the fate of impingement abnormalities we analyzed the contralateral hip in patients undergoing THA for advanced FAI. Our purpose was to determine the bilaterality of FAI abnormalities, and to describe the prognosis of these deformities.

Method: We reviewed 508 patients ≤50 years of age treated with THA. Radiographic review identified 70 hips that had OA secondary to FAI (71% cam, 5% pincer, 24% combined). Bilaterality was determined radiographically, and the fate of the contralateral hip was analyzed by determining radiographic presence and progression of OA, and the need for subsequent THA.

Results: 71% of the patients were male and the average age was 43.2 years. The contralateral hip was analyzed on radiographs over an average 9 year period (range, 4–30 years). 100% of the contralateral hips had radiographic features of FAI. 49 (70%) of the contralateral hips demonstrated degenerative disease. 14 had advanced OA at presentation, 41 had progressive joint space narrowing, 25 had progression of Tonnis OA grade and 26 underwent subsequent THA. Statistical analysis showed that alpha angle, LCEA, joint space width, and head-neck ratio have strong predictive value for subsequent THA (p< 0.05).

Conclusion: This study demonstrates that FAI abnormalities are commonly bilateral and are associated with OA progression in the majority of hips. Patients diagnosed with FAI should have both hips monitored, and joint preservation surgery or THA considered when appropriate.

Prism Schneider James N. Powell Gerhard N. Kiefer Bevan Frizzell

Purpose: Femoroacetabular impingement (FAI) results from abnormal abutment between the proximal femur and acetabulum (Ganz et al., 2003). FAI occurs in three forms; cam, pincer and mixed (cam and pincer combined). The cam type has been quantified radiographically (Beall et al., 2005), but pincer FAI is poorly defined. Radiographic measures, including the center-edge angle (Wiberg, 1953), and Sharp’s angle (Sharp, 1961) have been used to define hip dysplasia, but these measures have not been used to define FAI. The purpose was to test these measurements to compare pincer patients with controls.

Method: This study is a retrospective, observational analysis of anterior-posterior pelvic radiographs for control (N=76 hips; 40 patients) and pincer (N=20 hips; 19 patients) groups. Control radiographs were obtained from injury-free pelvic x-rays from the emergency department. Lateral center-edge (CE) angle Sharp’s angle and a proposed measurement of Femoral Head Containment (FHC) were measured using PACS. FHC was defined as the percentage of the 2D area of the femoral head circle covered by the acetabulum, using chord length, height and diameter of the femur head. Non-parametric statistics with post-hoc analyses were used. Pearson’s correlations were calculated for within- and between-observer reproducibility.

Results: Mean (± SD) CE angle was significantly larger in the FAI group [37.4° (±5.2)] compared to controls [31.0° (±3.9)]. Mean Sharp’s angle was significantly less in the FAI group [37.6° (±3.9)] compared to the controls [41.2° (±3.5)]. Mean FHC was significantly larger in the FAI group [26.4% (±5.3)] compared to control group [21.5% (±5.3)]. Intra-observer r-values ranged from 0.86–0.97 and inter-observer correlations ranged from 0.93–0.96. There was significantly greater acetabular overcoverage in the pincer group based on these three measures, suggesting these may be used diagnostically.

Conclusion: Pincer FAI is a debilitating condition that has not been quantified. This study found that CE angle, Sharp’s angle and FHC measures may be useful in diagnosing pincer FAI. A new method of quantifying FHC was proposed, evaluated and appears to be a promising new measure for evaluating pincer FAI. The CE and Sharp’s angles are simple, reproducible measures that can easily be used in a clinic setting to assist with diagnosing pincer FAI.

Scott D. M. Wotherspoon Kevin R. Willits Timothy J. Doherty

Purpose: The purpose of this study is to investigate the relationships of traction force, traction time, and hip distraction to the development of nerve conduction abnormalities during hip arthroscopy.

Method: Thirteen patients with hip pathology underwent hip arthroscopy. Traction forces applied to the operative leg were measured using a load-cell force transducer. Distraction of the hip joint was assessed using fluoroscopy. Nerve conduction studies of the tibial nerve was performed measuring the latency of the Hoffmann reflex (Hlat reflex). Measurements of the traction force, distraction of the hip, and nerve conduction studies were performed at routine intervals during the procedure, and compared to pre- and post-op values.

Results: Nerve Conduction Studies- The mean baseline Hlat reflex was 30.4+/−2.2 milliseconds for all patients. Three patients lost the Hlat reflex immediately (t=0), and an additional three patients lost the Hlat reflex during the procedure (t=30, t=30, t=60). The remaining seven patients all had delayed conduction of the Hlat reflex over time. At one-hour post-op, the Hlat reflex was documented in all patients (mean 31.9+/−2.9 ms) and remained significantly different from baseline (p< 0.01). Clinically, one patient in the lost Hlat reflex group had an associated neuropraxia post-operatively. Traction Forces- The mean initial traction force at time of application for all patients was 97+/−28 lbs. The mean initial traction force of the lost Hlat reflex group and retained Hlat reflex group was 104+/−32.6 lbs and 91+/−24.1 lbs, respectively (p=0.44). Hip Distraction- The mean initial hip distraction at time of application of traction for all patients was 8.8+/−2 mm. The mean initial distraction of the lost Hlat reflex group and retained Hlat reflex group was 9.6+/−1.4 mm and 8+/−2.2 mm, respectively (p=0.15).

Conclusion: Traction during hip arthroscopy is associated with significant nerve conduction abnormalities in the immediate post-operative period. Six of thirteen patients had complete loss of the Hlat reflex of the tibial nerve, one of these patients exhibiting clinical neuropraxia. Although length of time in traction may be a factor for the development of nerve conduction abnormalities, a more significant factor may be the change in length over time of the surrounding peripheral nerves.

Michael Tanzer Marie Gdalevitch Karen Smith

Purpose: The treatment and prognosis of labral tears secondary to femoroacetabular impingement depends on the severity of the labral injury and whether or not there is concomitant injury and delamination of the adjacent articular cartilage. At present, there is no simple and reproducible technique to determine if there is delamination of the adjacent articular cartilage. We undertook a study to determine if the preoperative presence of a previously undescribed radiographic finding, a “delamination cyst”, correlated with delamination of the articular cartilage at the time of hip arthroscopy.

Method: The preoperative radiographs of 125 consecutive hip arthroscopies in which a labral tear was identified intraoperatively were retrospectively reviewed.. In each case an anteroposterior (AP) pelvis and AP, lateral and frog lateral hip radiographs were evaluated for the presence of delamination cysts, perilabral cysts, abnormalities of the femur and acetabulum, as well as arthritic changes. A “delamination cyst” was defined as a subchondral cyst either directly adjacent to a perilabral cyst, or in relation to a subchondral crack in the anterolateral portion of the acetabulum. These findings were then compared and correlated to the intraoperative arthroscopic findings.

Results: We identified 16 patients with delamination cysts on radiographs and 15 patients with delamination of the acetabulum on arthroscopy. A strong correlation was found between the preoperative radiographic presence of a delamination cyst and acetabular delamination at the time of arthroscopy – sensitivity of 93.3%, specificity of 98.8%, positive predictive value of 93% and a negative predictive value of 99% (p=0.034). No other radiographic findings were associated with the status of the articular cartilage.

Conclusion: A “delamination cyst” is a previously undescribed and novel radiographic sign that can accurately predict preoperatively which patients with labral tears have associated acetabular cartilage delamination or chondral damage. Delamination cysts can be easily identified on plain radiographs without performing any special imaging or invasive infiltrations. Identifying these cysts preoperatively can aid the surgeon in selecting the appropriate surgical procedure and help predict the patient’s prognosis following the planned surgical procedure.

Christian Veillette Akin Cil Joaquin Sanchez-Sotelo John Sperling Robert Cofield

Purpose: We conducted a retrospective review to evaluate outcomes, complications and implant survival after shoulder reconstruction for bone neoplasm using anatomic shoulder prostheses.

Method: Thirty-four anatomic shoulder prostheses were reviewed at an average follow-up of 51 (range, 6 to 143) months. The mean age at the time of surgery was 47 (range, 15 to 74) years. Twenty-five patients (74%) had reconstruction with an allograft-prosthetic composite (APC). The average amount of humerus resected in patients with an APC was 13 cm (range, 5 to 36 cm).

Results: At most recent follow-up, 82% of patients had no pain (11), slight pain (12) or moderate pain with strenuous activities (5). Twenty-eight patients (82%) were subjectively satisfied despite only 29% being satisfactory according to Neer rating. Sixteen complications occurred in 13 patients, including instability (5), host/graft non-union (3), aseptic loosening (3), arthrofibrosis (1), tumor recurrence (2) and superficial infection (1). Host/graft nonunion occurred in 3/9 patients with an APC using press-fit or plate fixation for distal humeral fixation and 0/16 shoulders with cemented distal humeral fixation (p=0.02). Three implants required revision for aseptic loosening (1), host/graft nonunion (1) and instability (1). Kaplan-Meier survivorship at 10 years was 88% for implant revision and 80% for mechanical failure.

Conclusion: Reconstruction of the proximal humerus using an anatomic prosthesis after resection of bone neoplasms is associated with a low rate of mechanical failure but a moderate rate of shoulder instability. Cement fixation into the native distal humerus should be considered when reconstruction using an APC is required.

Buchi R. B. Arumilli Cheshire Crewe V. Lenin Babu Tahir Khan Ashok S. Paul Anthony Chan

Purpose: The literature on management of advanced soft tissue tumours is limited because of the rarity of cases following increased awareness and improved diagnostic resources.

Method: Our experience of managing 18 patients with fungating soft tissue tumours of the extremities and one patient with a sarcoma involving the scapular region (limb girdle) is presented. There were 14 males and 5 females. Average age was 70.6 yrs ranging between 37 – 98 years. 13 tumours involved lower limb and 6 the upper limb.

Results: The follow-up ranged from a minimum of 6 months to 10 years from the initial referral. The histological diagnosis was Sarcoma in 15 patients (Spindle cell sarcoma in 4, Fibrous Histiocytoma in 2, Pleomorphic sarcoma in 3, liposarcoma in 2, leiomyosarcoma in 2, Fibrosarcoma in 1 and 1 Round cell sarcoma). In the remaining 3 patients immunohistochemistry studies confirmed a Metastatic Squamous cell Sarcoma, a Metastatic Malignant Melanoma and a Metastases from a poorly differentiated upper GI malignancy each. Primary wide local excision was performed in 15 patients and primary amputation was performed in two patients. In 2 patients when tumour was unresectable due to the location and local spread, an embolisation was performed in both for palliation. Lung Metastases were present at the time of referral in 6 patients and developed later during follow-up in 4 patients. A histologically proven recurrence occurred in 6 patients after an average of 15.83 (4 to 41) months. Revision surgery was needed in 9 patients for either a positive margin on histology or a recurrence, including 3 secondary amputations. Local adjuvant Radiotherapy was given for 7 patients and a combination of radio and chemotherapy was used in 2 patients for metastases. Mortality was 53 % (9 patients) by the end of 32 months of follow-up.

Conclusion: Fungation in soft tissue tumours is rare and often a sign of locally advanced disease and a high grade nature, patients either have systemic spread by the time or develop later inspite of good local disease control. Primary wide local excision in such patients is difficult and has a high chance of a positive margin hence primary amputation may be better for local clearance. Recurrence of tumour and revision surgery is common and the mortality was > 50% at the end of 3 years from presentation to treatment in our series.

Yair Gortzak Gina Lockwood Ashish Mahendra Ying Wang Anthony Griffin Benjamin Deheshi Jay S. Wunder Peter C. Ferguson

Purpose: To formulate a scoring system enabling decision making for prophylactic stabilization of the femur following surgical resection of a soft tissue sarcoma (STS) of the thigh.

Method: A logistic regression model was developed using patient variables collected from a prospective database. The test group included 22 patients with radiation-related pathological femur fracture following surgery and radiation for a thigh STS. The control group of 79 patients had similar treatment but without a fracture. No patients received chemotherapy. Mean follow-up was 8.6 years. Variables examined were: Age (70 years), gender, tumor size (0–7, 8–14, > 14 cm), radiation dose (low=5000 cGy, high> 6000 cGy), extent of periosteal stripping (20 cm) and thigh compartment (posterior, adductor, anterior). A score was assigned to each variable category based on the coefficients obtained in the logistic regression model.

Results: Based on the regression model and an optimal cut-point, the ability to predict radiation associated fracture risk was 91% sensitive and 86% specific. The area under the Receiver Operating Characteristic (ROC) curve was 0.9, which supports this model as a very accurate predictor.

Conclusion: Radiation-related femur fractures following combined surgery and radiation treatment for STS are uncommon, but are difficult to manage and their non-union rate is extremely high. These results suggest that it is possible to predict radiation-associated pathological fracture risk with high sensitivity and specificity. This would allow identification of high risk patients and treatment with prophylactic IM nail stabilization. Presentation of this model as a clinical nomogram will facilitate its clinical use.

Marc J. Philippon Karen K. Briggs David A. Kuppersmith

Purpose: This purpose of this study was to report 2 year outcomes following hip arthroscopy for the treatment of femoroacetabular impingement and chondrolabral dysfunction and determine factors associated with outcomes.

Method: Between 3/2005 and 10/2005, 122 patients underwent hip arthroscopy by a single surgeon. Patients were included if they underwent arthroscopic treatment for FAI and chondrolabral dysfunction. All patients were prospectively enrolled in an IRB approved follow-up study. Ten patients refused to participate following enrollment.

Results: At arthroscopy, for treatment of impingement, 23 patients underwent only osteoplasty for CAM impingement, 3 patients underwent only rim reduction for pincer impingement and 86 patients underwent osteoplasty and rim reduction for mixed type impingement. Ten patients underwent total hip arthroplasty at an average of 16 months (range: 8–26) after arthroscopy. Average follow-up was obtained on 90%(92/102) at 2.3 years (range: 2.0–2.9). The modified Harris Hip score(MHHS) improved from 57 to 84. HOS ADL improved from 69 to 88. HOS Sport improved from 41 to 69. NAHS improved from 64 to 82. All scores significantly improved (p< 0.05). The average patient satisfaction was 8.4 (range: 1–10). All patients returned to work (15% returned within 1 week, 53% returned in 1–5 weeks, 18% returned in 6–8 weeks, 13% returned in 2 to 6 months). Ten patients underwent THA at an average of 16 months. These patients were significantly older at arthroscopy (58 vs. 39;p=0.0001), had significantly less joint space at all 3 weight bearing surfaces (p=0.001), and patients with microfracture on both femoral head and acetabulum were more likely to undergo THA (p=0.001). The predictors of higher post-operative MHHS were preoperative modified Harris Hip score (p=0.018), joint space of 2mm or greater(p=0.005), and repair of labral pathology instead of debridement (p=0. 032)(r2=0.32;p=0.001). Patients with labral repair had higher MHHS compared to patients with labral debridement (87vs81). Independent predictors of patient satisfaction were postoperative MHHS(p=0.001) and joint space of 2mm or greater(p=0.040) (r2=0.67; p=0.001).

Conclusion: Hip arthroscopy for femoroacetabular impingement accompanied by the prescribed rehabilitation led to return to excellent function and high patient satisfaction. Factors associated with higher outcomes included joint space of greater than 2mm, and labral repair for treatment of labral pathology.

John E. Handelsman Jacob Weinberg

Purpose: Femoral torsion is traditionally treated by a proximal osteotomy. At this level, a significant exposure is required. Furthermore, internal fixation is typically removed by additional surgery at twelve months. We propose to demonstrate the efficacy of the AO external fixator to maintain osteotomies in the distal femur for torsional correction.

Method: Between September 1994 and April 2001, supracondylar osteotomies were performed on 38 femora in 21 children with torsional and angular deformities. The average age at presentation was 10 years. Twenty-three femora had excessive anteversion and 15, retroversion. The technique required the lateral placement of three 4.0 mm end-threaded Schanz pins parallel to the distal growth plate. Three similar pins were inserted more proximally in line with the femoral shaft. A transverse osteotomy was performed through a limited lateral approach. After correction of the deformities, each pin was linked to all others by clamps and carbon fiber rods.

Results: Lower extremity alignment was restored in all patients. Genu valgum was addressed in eighteen osteotomies. Five extension osteotomies were performed for fixed knee flexion deformities. The external fixators were removed at an average of ten weeks. One child had a superficial pin tract infection requiring intravenous antibiotics. All osteotomies united without complications. No postoperative femur fractures occurred.

Conclusion: Osteotomy at the distal femur has the advantage of correcting both torsional and angular deformities. The exposure required is limited. The AO external fixator provides precise control of the osteotomy and allows for subsequent adjustability. This method effectively controls supracondylar osteotomies and avoids a second procedure for hardware removal.

Michael G. Vitale Salih Marangoz Jaime A. Gomez Harold J. P. van Bosse Joshua E. Hyman David S. Feldman Debra A. Sala Matthew Stein

Purpose: Use of six-axis analysis and computer assisted deformity correction via a circular external fixator is a new method for deformity correction. We investigated its accuracy and safety in reconstruction of femoral deformity in children and young adults.

Method: We retrospectively reviewed all cases including the indications for use and the methodology of application of the computer assisted six-axis analysis and circular external fixator for reconstruction of 22 femora in 20 patients. Twelve patients were female, and 8 were male. The average age was 13.9 (range, 5.9–24.6). Etiology included traumatic (7), idiopathic (6), multiple enchondromatosis (2), rickets (2), congenital femoral deficiency (2), spondyloepiphyseal dysplasia (1), congenital pseudohypoparathyroidisim (1), and multifocal osteomyelitis (1). Clinical and radiographic data were analyzed.

Results: Average follow-up was 14.4 months (range, 4.5–32). Average time in frame was 6.2 months (range, 2.6–19). Bone lengthening of 3.9 cm (range, 1–8.5) was performed in 12 femora. In genu valgum patients, the mLDFA improved from a mean of 73.7° to a mean of 89°. In genu varum patients, the mLDFA improved from a mean of 99.8° to a mean of 89.5°. Complications included pin tract infection in 6, knee stiffness in 3, delayed union in 2, skin irritation in 1, posterior knee subluxation in 2, both of which had stable knees preoperatively. One patient was lost to follow-up and returned back with deformity. No complications occurred in 8 patients.

Conclusion: Computer assisted femoral deformity correction with six-axis analysis and application of circular external fixator is a useful technique with the advantage of managing multiplanar deformities in children and young adults. It has the potential complications of the use of any external fixator. Close follow-up is necessary to avoid subluxation of the knee joint even in patients with stable knees. Accurate and safe correction can be achieved in almost all patients.

Daniel Latt Robert E. Turcotte Marc H. Isler Cindy Wong

Purpose: To review all cases of soft tissue sarcoma of the foot and ankle treated in a specialized musculoskeletal oncology practice over a 15 year period. This was done to gain insight into the presentation, treatments, and outcomes for this rare disease.

Method: 16 patients (mean age at presentation 43, range 15–79, 9 female) were identified from our database of nearly 1000 cases of musculoskeletal tumors (1.6%). 8 were referred following unplanned excision and 3 after local recurrence. The pathologic diagnoses included synovial sarcoma (n=7), clear cell sarcoma (n=2), fibrosarcoma (n=2), and other diagnosis (n=6). AJCC stages were: Ia – 2, IIb – 7, IIc – 1, III – 4, and IV – 2. The tumors were mostly located on the medial (n=7) or dorsal (n=6) aspects of the foot. They were equally distributed among the hindfoot, midfoot, and forefoot.

Results: Treatment consisted of resection in 10, resection and arthrodesis in 3, and amputation in 4 patients. The resections were intralesional in 4 patients, marginal in 7 and wide in 6. Among the 13 limb salvage patients, one needed skin grafting and 9 required free tissue transfers. Radiation therapy was used preoperatively in 5 and post-operatively in 7 cases. Neoadjuvant chemotherapy was given to 2 patients. Followup averaged 6 years (range 2–15). Local recurrence occurred in 2 patients (17%). One was treated with re-excision and one with amputation. Lung metastases occurred in 4 patients. At last followup: 11 of the 17 patients were alive without disease, 2 with disease, and 4 had died of their disease. No local recurrence in primarily treated tumor led to metastasis. Postoperative MSTS 1987 and TESS scores averaged 28 and 90% respectively.

Conclusion: Soft tissue sarcoma of the foot is rare. Surgical treatment is challenging due to the complex anatomy and limited soft tissues. Limb salvage often required accepting intralesional or marginal resections and using free tissue transfer. The addition of radiation therapy yielded an acceptable local control rate and very good functional outcomes. However, the impact this limb salvage approach on mortality is not clear.

Anna Kulidjian Benjamin Deheshi Peter C. Ferguson Jay S. Wunder Robert S. Bell Anthony Griffin

Purpose: To review the oncologic outcomes following treatment of soft tissue sarcomas in the foot and ankle, and to determine the results of limb salvage surgery in this anatomically constrained area with often expected close pathologic margins.

Method: One hundred twenty-nine patients with soft tissue sarcomas of the foot were treated at our institution since 1986. Average age at presentations was 55 years old. Females and males were equally represented. Most common diagnosis was MFH in 31 patients, followed by leiomyosarcoma in 16 patients, synovial sarcoma in 13, and clear cell sarcoma in 6, the remainder being other soft tissue sarcomas. Most of sarcomas were intermediate or high grade. Our follow-up averaged 58 months.

Results: Limb salvage surgery was possible in 97 patients. Of those, negative margin excision was achieved in 75 patients, 18 patients had micro-positive margins, and 4 had grossly positive margins. Fifty-three patients in the limb salvage group required free tissue transfer for coverage. Of 97 limb salvage patients, 82 received radiation therapy, 5 patients received chemotherapy. Local recurrence occurred in 24 patients. Two of these were amenable to re-excision, the remaining required amputation. Thirty-two patents developed systemic disease. Average disease-free survival for patients with recurrent disease was 23 months. At last follow-up, 78 patients were alive with no evidence of disease and 24 were alive with disease. Seventeen patients died of disease