Introduction: Vertebroplasty increases stiffness and partly restores normal load-sharing in the human spine following vertebral fracture. The present study investigated whether the mechanical effects of vertebroplasty are influenced by the distribution of injected cement.

Methods: Ten pairs of cadaver motion segments (58–88 yr) were loaded to induce fracture, after which one from each pair underwent vertebroplasty with polymethyl-methacrylate cement, the other with a resin (Cortoss). Various mechanical parameters were measured before fracture, after fracture and following subsequent vertebroplasty. Micro-computed tomography scans and plane radiographs (sagittal, frontal, and axial) obtained from each augmented vertebral body were analysed to determine percentage cement fill in the whole vertebral body and in selected regions. The relationship between volumetric fill obtained by micro-CT and areal fill obtained by radiography was investigated using linear regression analysis. Regression analysis also indicated whether changes in mechanical parameters following vertebroplasty were dependent upon cement distribution.

Results: Cement type had no significant influence upon regional fill patterns, so data from both cements were pooled for all subsequent analyses. Volumetric fill of the whole vertebral body was predicted best by areal fill in the sagittal plane (R2=0.366, P=0.0047). Restoration of intradiscal pressure and compressive stiffness following vertebroplasty were dependent upon volumetric cement fill both in the whole vertebral body (R2=0.304, P=0.0118 and R2=0.197, P=0.0499 respectively), and in the anterior half (R2=0.293, P=0.0137 and R2=0.358, P=0.0053).

Conclusion: Cement fill patterns can best be assessed radiographically from sagittal plane views. Placement of cement in the anterior vertebral body may help to improve mechanical outcome following vertebroplasty.

Total hip arthroplasty (THA) allows patients to return to an active lifestyle. Unfortunately one of the more common complications of cementless THA is a fracture of the greater trochanter (GT) or the calcar. These may compromise the outcomes of THA, but there are no large studies looking into this hypothesis.

Between September 1998 and August 2005 the Hamilton Arthroplasty group performed 2282 THA operations. Demographic and outcome data on these patients was collected and tabulated in a prospective database. Radiographs were available on a picture archiving system for 1075 of the patients, 85% of which were primary THAs. GT and calcar fractures were identified. Statistical comparisons on the normal distributed outcome data were made using the Student’s T-test comparing repaired and missed fractures.

A total of 60 GT fractures were found in the review of 1075 radiographs, giving an incidence of 5.6%. This included 19 isolated GT fractures and 10 GT fractures with associated calcar fractures that were found in primary hip arthroplasties, 48% of the total. Revision hip surgeries had 14 isolated GT fractures and 17 GT fractures with associated calcar fracture. We found that 23 (40%) of all GT fractures were missed intra-operatively and did not receive any fixation. All calcar fractures were noted and repaired, even if the associated GT fracture was not.

106 isolated calcar fractures were noted, 10% of all arthroplasties, only one of which did not receive fixation. Of this, 85 (80%) were from primary total hip arthroplasty and 21 (20%) from revision hip arthroplasty.

Evaluation of the outcome data showed no significant difference between repaired and missed GT fractures. Reported outcomes compared favourably with the average for all THA in that time period.

Adoption of cementless total hip arthroplasty in North America undoubtedly increases the rate of GT and calcar fractures. Most calcar fractures were noted and fixed but only 50% of GT fractures were discovered intraoperatively, an area of potential improvement. Greater trochanter and recognized calcar fractures may not have long-term detrimental effects.

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 evidence is just developing in the literature as to gender specific outcomes. We hypothesised that outcomes in arthroplasty patients are affected by gender.

Methods: 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 Harris Hip/Knee Society Score and Oxford Hip/Knee scores. These were compared to determine differences, if any, between males and females using independent samples t-test.

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 had differing rates of comorbidities and complications. Female KSS, Oxford and ROM outcomes were significantly inferior to male scores preoperatively and at 1 year follow up. Significantly more females reported higher pain scores than males from pre-op to 1 year. Interestingly, females showed significantly more improvement from pre-op to 1 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 improvements from pre-op to 1 year in both outcome scores.

Conclusion: As reported in the literature, results of this study indicate that women choose TJR 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 1 year. Surgeons must counsel females differently about expectations and recovery in joint arthroplasty.

Introduction: Unilateral posterior Pelvic Ring injuries but especially bilateral sacral fractures or bilateral sacroiliac joint (SI) ruptures as well as lumbosacral dislocations and fracture dislocations remains a significant surgical challenge.^1,2,3 despite advances in surgical techniques. Although the true incidence of these fractures are unknown, 30% are identified late.⁴

The treatment of those fractures varies from conservative treatment, posterior plate fixation, anterior plating as well as percutaneous and open Sacroiliac (SI) joint screws.

However, screw pull-outs and loss of fixation in those methods are well described In the Alfred Hospital, Melbourne (Australia) a Level 1 Trauma Center a series of 14 patients were treated from 10/2006 to date with a multiaxial spinal system.

Methods: Patients with posterior pelvic injuries separation were identified prospectively since October 2006. Data was extracted from the trauma registry database and medical record and diagnostic imaging. Since Ocober 2006, 10 patients with bilateral posterior pelvic ring injuries and 4 with unilateral injuries were identified for fixation.

Technique: The patients were put supine and a incision medial/distalto the posterior iliac spine was made. The placement for the incision gives the surgeon the opportunity to estend the approach to an open reduction of the sacral fracture or SI Joint disruption if a closed reduction cannot be achieved.

A pedicel screw from a multiaxial spinal system (Xia, Stryker or Pangea, Synthes) is placed percutaneously in the posterior iliac crest on both sides and the reduction is performed with the screws attached to the screw handles and with Image Intensifier.

After the reduction the multiaxial screwheads are bent and transfixed with a bar which is tunneled epifacial.

All patients underwent a multislice pelvic and lumbar spine CT and these patients were assessed clinically for neurovascular symptoms and stability. The follow-up included clinical assessment and CT imaging.

Results: Since October 2006 14 patients (10 male, 4 female) with an average age of 32.4 years (range: 20–44 years, median 33 years) and an average ISS (Injury Severity Score) of 37 (range: 14–66, median 34). The mechanism of injury for these patients included: pedestrians versus car; motorcylce; paragliding and motor car collision. All patients had associated anterior pelvic ring injuries which were internally fixed in all but one case.

The follow up time was one to 18 month. The patients were assessed clinically and with CT imaging. No complications or loss of fixation have been observed in this patient group in this short follow up time.

Discussion: The fixation system is highly versaitle and the whole posterior iliac crest can be used for fixation. The posterior instrumentation provides also a good control of the reduction of anterior pelvic ring fractures which should be fixed when associated. In all cases but 3 the nature of the comminuted sacral fractures did not allow the use of SI-Joint screws or anterior SI-Joint plating.

The construct provides initial stability and allows mobilization of the patient. It can be used in cases with sacral comminution and may offer advantages over posterior plate fixation, by reducing complications with prominent metalware.

Endoprosthetic replacement is often the preferred treatment for neoplastic lesions as internal fixation has been shown to have a high failure rate. Due to anatomical location, disease factors and patient factors internal fixation may be the treatment of choice. No reports exist in the literature regarding the use of locking plates in the management of neoplastic long bone lesions.

Data was collected prospectively on the first 10 patients who underwent locking plate fixation of neoplastic long bone lesions. Data was collected on the nature of the lesion, surgery performed, complications and outcome.

The patients mean age was 56.6 (15–88). Six lesions were metastatic, one haematological (myeloma) and 3 were primary bone lesions (lymphoma, Giant cell tumour, simple bone cyst). In nine cases a fracture through the lesion had occurred. Anatomical locations of the lesions were; proximal humerus (four), proximal tibia (three), distal femur (two) and distal tibia (one). Cement augmentation of significant bone defects was necessary in seven cases.

The mean hospital stay was 8 days (3–20). There were no inpatient complications. Five patients received adjuvant radiotherapy and one patient received neo-adjuvant radiotherapy to the lesion. There have been 3 deaths. All were due to metastatic disease and occurred between 6 and 12 months after surgery. The mean follow up in the surviving patients is currently 9 months (5–16). There have been no fixation related complications. Patients who had suffered a fracture had restoration of their WHO performance status. At last follow up the mean MSTS was 78% (57–90) for lower limb surgery and 70% (63–76) for upper limb surgery. These figures compare favourably with the results of endoprosthetic replacement.

The early results of locking plate fixation for neoplastic long bone lesions are excellent. Follow up continues to observe how these devices perform in the long term.

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.

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.

Pelvic fractures in multi-trauma patients are an indicator of severe trauma and often require advanced wound management of pelvic, abdominal or extremity injuries. Poor wound management may result infected pelvic hardware, necessitating revision surgery. We propose that TNP is a safe method of wound management and report our experience.

In 2006 91 multi-trauma patients required pelvic/ace-tabular fixation at The Alfred, either internal or external. Of those, 23 needed TNP for wound care of pelvic, abdominal or extremity injuries. Indications for TNP included Morel-Lavelle lesions, concomitant bladder disruption with anterior wounds, severe edema preventing any wound closure, extremity open fractures/degloving/fasciotomies and post-op infections.

The average age of the group was 33, the average injury severity score was 36, 5 were female, 18 were male. There was one pelvic wound infection that resolved with TNP and local wound care. Two unsalvageable limbs (one transhumeral, one transfemoral) required amputation after TNP, all others were either closed primarily or with a flap and skin graft. There was one death in the group from unrelated causes. Pelvic scores, SF-12, visual analog pain scores and sexual dysfunction rates are being gathered and will be reported.

Topical negative pressure is a safe and effective method of managing complex wounds in multi-trauma patients with pelvic injuries.

Introduction: The aim of this cadaver study was to examine how cement volume used in vertebroplasty influences the restoration of normal load-sharing and stiffness to fractured vertebrae.

Methods: Nineteen thoracolumbar motion segments obtained from 13 spines (42–91 yrs) were compressed to failure in moderate flexion to induce vertebral fracture. Fractured vertebrae underwent two sequential vertebroplasty treatments (VP1 and VP2) each of which involved unipedicular injection of 3.5ml of polymethyl-methacrylate cement. During each injection, the volume of any cement leakage was recorded. At each stage of the experiment (pre-fracture, post-fracture, post-VP1 and post-VP2) measurements were made of motion segment stiffness, in bending and compression, and the distribution of compressive stress across the disc. The latter was measured in flexed and extended postures by pulling a pressure transducer through the mid-sagittal diameter of the disc whilst under 1.5kN load. Stress profiles indicated the intradiscal pressure (IDP), stress peaks in the posterior annulus (SPP), and neural arch compressive load-bearing (FN). Measurements obtained after VP1 and VP2 were compared with pre-fracture and post-fracture values using repeated measures ANOVA to examine the effect of cement volume (3.5 ml vs. 7 ml) on the restoration of mechanical function.

Results: Fracture reduced compressive and bending stiffness by 50% and 37% respectively (p< 0.001) and IDP by 59%–85%, depending on posture (p< 0.001). SPP increased from 0.53 to 2.46 MPa in flexion, and from 1.37 to 2.83 MPa in extension (p< 0.01). FN increased from 11% to 39% of the applied load in flexion, and from 33% to 59% in extension (p< 0.001). VP1 partially reversed the changes in IDP and SPP towards pre-fracture values but no further restoration of these parameters was found after VP2. Bending and compressive stiffness and FN showed no significant change after VP1, but were restored towards pre-fracture values by VP2. Cement leakage occurred in 3 specimens during VP1, and in 7 specimens during VP2. Leakage volumes ranged from 0.5–3.0 ml, and were larger during VP2 than VP1.

Conclusions: Unipedicular injection of 3.5 ml of cement reversed fractured induced changes in IDP and SPP, but did not affect stiffness and neural arch load-bearing. Larger injection volumes may provide some extra mechanical benefit in terms of restoring stiffness and reducing neural arch loading, but these extra mechanical benefits can be at the cost of increased risk of cement leakage.

Thinning of the femoral neck occurs in 77% of patients undergoing hybrid Birmingham hip resurfacing using a posterior approach (Shimmin 2007). Villar recently reported lower neck thinning rates in uncemented Cormet resurfacings (11.7%) compared with hybrid Birmingham resurfacing (13.4%), both via a posterior approach.

We have evaluated implant position and femoral neck thinning in a cohort of 273 uncemented HA coated Cormet 2000 hip resurfacings using ‘B’-series (Titanium/HA coated) cups in 269 patients (mean age 54 years, 39% female) with a mean follow-up of 3 years (range 1–4 years).

Mean cup inclination was 45° (30°–63°), mean SSA 138° (120°–178°). No lucent or sclerotic zones have been identified around the stem of the component. Only one femoral neck fracture has occurred (incidence 0.36%)

We have identified only one case of femoral neck thinning in our series (0.36%).

Whilst Villar has demonstrated a slight reduction in neck thinning rates using the same implants compared to a hybrid fixation Birmingham resurfacing, his neck thinning rates are almost 40 times higher than in our series. Shimmins ‘severe neck thinning (> 10%) rates (27%) are approximately 120 times higher than our series. In addition, we have been unable to confirm the relationship between implant position and neck thinning described by Shimmin in our series using the combined Ganz/uncemented resurfacings compared with Birmingham resurfacings.

Implant design and surgical approach have an impact on ‘neck thinning after resurfacing; we should be wary of treating all resurfacing implants and techniques as a uniform cohort.

The purpose of the study was to determine how suture materials commonly used in arthroscopic surgery were affected by electrocautery. The effects of electrocautery were evaluated on four different suture materials commonly used in arthroscopic surgery; PDS, Ethibond, Orthocord and Fibrewire. Single suture strands were tied around two plastic rods immersed in a saline filled water bath at 37°C. Sutures were exposed to heat using the Mitek VAPR 3 electrosurgical unit and a corresponding side electrode. This was used on the high intensity vaporisation setting, at a power level of 240W. The electrode was applied directly to the suture strand, under tension, until the strand was completely burnt through. Fibrewire demonstrated a significantly higher burn through time in comparison to the other materials tested (83.30±38.69s, p< 0.001). Orthocord also demonstrated high heat tolerance (38.96±12.64s), which was significantly higher than both PDS (1.61±0.25s) and Ethibond (0.93s±0.06s) (p< 0.001). This is the first study to our knowledge assessing the tolerance of suture materials to electrocautery. This has important implications for the arthroscopic surgeon. On completion of an arthroscopic repair, the surgeon must always be extremely cautious, for fear of damaging the suture material and compromising their soft tissue repair. This study demonstrates that both Fibrewire and Orthocord can tolerate prolonged, direct heat application from electrocautery. We therefore conclude that short bursts of soft tissue vaporisation, after completing an arthroscopic repair with Fibrewire or Orthocord, are unlikely to have a detrimental effect on the suture material. However care should be exercised by the surgeon using Ethibond or PDS.

Introduction: Kyphoplasty is a modification of the basic vertebroplasty technique used to treat osteoporotic vertebral fracture. This study evaluated whether kyphoplasty conferred any short-term mechanical advantage when compared with vertebroplasty.

Methods: Pairs of thoracolumbar “motion segments” were harvested from nine spines (42–84 yrs). Specimens were compressed to failure in moderate flexion to induce vertebral fracture. One of each pair underwent vertebroplasty, the other kyphoplasty. Specimens were then creep loaded at 1.0kN for 2 hours to allow consolidation. At each stage of the experiment, motion segment stiffness in bending and compression was determined, and the distribution of compressive “stress” was measured in flexed and extended postures by pulling a pressure- sensitive needle through the mid-sagittal diameter of the disc whilst under 1.5kN load. Stress profiles indicated the intradiscal pressure (IDP), stress peaks in the posterior annulus (SPP), and neural arch compressive load-bearing (FN).

Results: Vertebral fracture reduced bending and compressive stiffness by 37% and 55% respectively (p< 0.0001), and IDP by 55%–83%, depending upon posture (p< 0.001). SPP increased from 0.188 to 1.864 MPa in flexion, and from 1.139 to 3.079 MPa in extension (p< 0.05). FN increased from 13% to 37% of the applied load in flexion, and from 29% to 54% in extension (p< 0.001). Vertebroplasty and kyphoplasty partially reversed these changes, and their immediate mechanical effects were mostly sustained after creep-loading. No differences were found between vertebroplasty and kyphoplasty.

Conclusion: Kyphoplasty and vertebroplasty are equally effective in reversing fracture-induced changes in motion segment mechanics. In the short-term, there is no mechanical advantage associated with kyphoplasty.

The rate of homologous blood transfusion (HBT) following primary total hip replacement (THR) can be as high as 30–40% and is not without risk. Postoperative blood salvage (POS) with autologous blood transfusion may minimize the necessity for HBT but the clinical, haematological and economic benefits have yet to be clearly demonstrated for primary THR.

The aim of this randomized prospective study was, therefore, to determine if the use of post-operative salvage affects post-operative haemoglobin and haematocrit values and reduces the rate of homologous blood transfusion. Secondary outcome measures included length of hospital stay and patient satisfaction. A cost analysis was also conducted on the basis of the results obtained.

The patients were randomized during the operation (at the point of reduction of the primary THR) to receive either two Medinorm vacuum drains or the autologous retransfusion system. A power calculation estimated that 72 patients would be required in each group to detect a significant difference of 0.7 gdL-1 in post operative haemoglobin level (at 80% power with an value of 0.05). This assumed a standard deviation of 1.5 gdL-1 obtained from a previous retrospective study.

There were 82 patients in the Medinorm vacuum drain group and 76 patients in the autologous retransfusion group. In the group with the autologous system, 76% of the patients were retransfused with a mean of 252mls. There was no significant difference between the groups when comparing haemoglobin and haematocrit values. However, significantly fewer patients in the group with the autologous system had a postoperative haemoglobin value less than 9.0 gdL-1 (8% vs. 20%, p = 0.035). Furthermore, significantly fewer patients with the autologous retransfusion system required a transfusion of homologous blood (8% vs. 21%, p = 0.022). There was a small overall cost saving in this group.

This study has shown that use of an autologous retransfusion system for primary THR reduces the necessity for HBT and is cost effective. POS also results in significantly fewer patients dropping their post-operative haemoglobin level below 9.0 gdL-1. As a result our unit routinely uses the autologous retransfusion system for primary THR.

Purpose of the study: To determine if cement type, bone mineral density (BMD), disc degeneration and fracture severity influence the restoration of spinal load-sharing following vertebroplasty.

Methods: Fifteen pairs of thoracolumbar motion-segments (51–91 yrs) were loaded to induce fracture. Vertebroplasty was performed so that one of each pair was injected with Cortoss, the other with Spineplex. Specimens were then creep loaded at 1.0kN for 2 hours. At each stage of the experiment, stress” profiles were obtained by pulling a pressure-sensitive needle through the disc whilst under 1.5kN load. From these profiles, the intradiscal pressure (IDP), posterior stress peaks (SP_P), and neural arch compressive load (F_N) were determined. BMD was measured using dual photon X-ray absorptiometry. Severity of fracture was quantified from height loss.

Results: Fracture reduced IDP (p< 0.001) but increased SP_P and F_N (p< 0.001). Following vertebroplasty, these effects were significantly reversed, and in most cases persisted after creep-loading. However, no differences were observed between PMMA- and Cortoss-injected specimens. After fracture, decreases in IDP, and increases in SP_P and F_N, were greater in specimens with lower BMD or greater height loss (p< 0.05). After vertebroplasty, specimens with lower BMD showed greater increases in IDP, and those with more degenerated discs showed greater reductions in SP_P (p< 0.05).

Conclusions: Changes in spinal load-sharing following fracture were partially restored by vertebroplasty, and this effect was independent of cement type. The effects of fracture and vertebroplasty were influenced by BMD, disc degeneration, and fracture severity. People with more severe fractures, low BMD and degenerated discs may gain most mechanical benefit from vertebroplasty.

Introduction: We have shown that vertebroplasty increases stiffness and partly restores normal load-sharing in the human spine following vertebral fracture. The present study investigated how this restorative action is influenced by type of cement injected, bone mineral density (BMD), and fracture severity.

Methods: Fifteen pairs of thoracolumbar motion-segments (51–91 yrs) were loaded on a hydraulic materials testing machine to induce vertebral fracture. One from each pair underwent vertebroplasty with polymethyl-methacrylate (PMMA) cement, the other with a biologically- active resin (Cortoss). Specimens were then creep loaded at 1.0kN for 2 hours. At each stage of the experiment, bending and compressive stiffness were measured, and ‘stress’ profiles were obtained by pulling a pressure-sensitive needle through the disc whilst under 1.5kN load. Profiles indicated the intradiscal pressure (IDP) and neural arch compressive load (FN). BMD was measured using dual photon X-ray absorptiometry. Severity of fracture was quantified from height loss. Changes were compared using repeated measures ANOVA.

Results: Fracture reduced bending and compressive stiffness by 31% and 41% respectively (p< 0.0001), and IDP by 43%–62%, depending upon posture (p< 0.001). In contrast, FN increased from 14% to 37% of the applied load in flexion, and from 39% to 61% in extension (p< 0.001). Following vertebroplasty, these effects were significantly reversed, and in most cases persisted after creep-loading. No differences were observed between PMMA- and Cortoss-injected specimens. The decrease in IDP and increase in FN after fracture were correlated with BMD in flexion and with height loss in extension (p< 0.01). After vertebroplasty, restoration of IDP and FN in flexion were correlated with their loss after fracture (p< 0.01). The former was also related to BMD (p< 0.05).

Conclusions: Changes in spinal load-sharing following fracture were partially restored by vertebroplasty, and this effect was independent of cement type. The effects of fracture and vertebroplasty on spinal load-sharing were influenced by severity of fracture, and by BMD.

These findings suggest that people with more severe fractures and low BMD may gain most mechanical benefit from vertebroplasty.

Scarf osteotomy improves hallux valgus and can be used for deformities with large intermetatarsal angles. It is designed to minimise shortening of the first ray. The aim of this radiographic analysis was to assess the outcome of patients undergoing Scarf osteotomy at the Royal Cornwall Hospital.

The initial 18 consecutive cases performed by the senior author were analysed using the guidelines recommended by the American Foot and Ankle Society. Standardised anterior-posterior radiographs of the foot were compared pre-operatively and at 6 weeks postoperatively. Measurements of the intermetatarsal angle (IMA), hallux valgus angle (HVA), joint congruency angle (JCA), distal metatarsal articular angle (DMAA), sesamoid position and metatarsal length were used to assess any improvement.

The results showed a significant median reduction of the IMA of 70, HVA of 180, JCA of 50, and the DMAA of 30 (all p values < 0.001). The medial sesamoid position in relation to the first metatarsal also improved from a mean value of 2.28 to 1 using the American Foot and Ankle Society grading system. There was no shortening of metatarsal length as measured using the Hardy and Clapham method.

This study shows that the radiographic outcome of Scarf osteotomy at the Royal Cornwall Hospital compares favourably with that found in the literature. It provides effective correction of moderate to large intermetatarsal angles.

It is known that activity level correlates with wear in total joint arthroplasty. UCLA activity score surveys were sent to four hundred and sixty-seven knee and hip arthroplasty patients with good/excellent clinical outcomes as determined by one-year postoperative Knee Society (KSS) and Harris Hip (HHS) scores. The UCLA activity score was correlated with clinical outcomes and demographic data. Average UCLA score was 6.2 for hips, 6.3 for knees, indicating moderate activity levels. Hip arthroplasty UCLA score significantly correlated with age, gender and one-year Oxford score. Knee arthroplasty UCLA score significantly correlated with gender, one-year functional KSS and Oxford score.

Arthroplasty patients are often warned to avoid high level activities for fear of implant loosening, failure or increased polyethylene wear. Patients with good/excellent clinical outcomes may however be inclined to participate in higher demand activities. There is need for specific information regarding patient profile and activity level following TJR.

Current recommendations for activity among TJR patients may not be justified. Longer-term follow-up will elucidate specific activities which may be permissible or detrimental to implant survivorship.

Survey response rate was 70.2% among THA patients at mean 40.7months. Mean UCLA score was 6.2/10, indicating moderate activity. Mean outcome scores; one-year HHS 94.8, Oxford 6.6. UCLA score significantly correlated with age, gender and one-year Oxford.

Survey response rate was 81.8% among TKA patients at mean 36.6months. Mean UCLA score was 6.3/10, indicating moderate activity. Mean outcome scores; one-year KSS clinical 95.9, KSS function 95, Oxford 18.2. UCLA score significantly correlated with gender, one-year KSS function and Oxford.

No significant differences among clinical outcomes and survey non-respondents.

UCLA activity score survey of two hundred and twenty-five primary TKA and two hundred and forty-two primary THA patients. Patients abstracted from prospective database and pre-selected for good/excellent outcomes based on KSS and HHS at one-year. Clinical outcomes included Oxford Hip/Knee scores. UCLA, demographics and clinical outcomes correlated using Pearson’s correlation.

UCLA scores indicate the average TJR patient maintains a moderate activity level. Younger male patients with low Oxford can be expected to participate in higher level activities. One THA patient underwent subsequent revision despite moderate activity level.

Decreased head-neck ratio diameter and component malposition in total hip arthroplasty are factors known to result in impingement, increased rates of dislocation, wear and failure. In addition to these complications, impingement of the femoral neck on the acetabular component of a hip resurfacing may result in femoral neck fracture and loosening of the acetabular component. Little is known regarding the optimum femoral and acetabular hip resurfacing component position to avoid impingement.

In the first part of this study we analysed the radiographic component position of 131 consecutive hip resurfacings. In the second part the effect of three component variables on the range of motion to impingement were analysed using a dry bone model:

Inclination of the acetabular cup

The mean femoral-stem shaft angle in the first part of the study was 138° (range 121° to 158°). The mean acetabular inclination angle was 45° (range 30° to 63°). This wide range in position mirrors that described in the literature. The dry bone study revealed an optimum acetabular cup inclination tending towards 50° and an anteversion of 25°. A large diameter femoral head relative to the femoral neck resulted in a greater range of motion to impingement. A fine balance however exists, to remove a minimum amount of pelvic bone to accommodate a larger acetabular component with an ‘oversized’ femoral component.

The acetabular resurfacing cup positions described allow the greatest range of physiological hip movement. New technology and improvements to existing equipment and techniques will hopefully lead to more accurate placement of hip resurfacing components minimising the risk of impingement and its complications in this high demand group of patients

Background: More patients are turning to the Internet for health-related information. Studies indicate that this information is being used to make decisions about their management. The aim of this study was to assess the information available specific to scoliosis on the Web using four common search engines.

Methods: Four search engines (Google, Yahoo, Hotmail and Ask Jeeves) were used in scanning the Web for the following key word- “Scoliosis”. Both U.K. only and World Wide sites were accessed. Four Spinal Surgery Consultants independently graded each site for layout, content, relevance to patients as opposed to medical professionals, ease of use and links to other sites. Each point was marked on a scale of 0–2 and a total of 10 points available. Web sites were assessed via U.K. search engines and forty via World Wide search engines. Good was awarded to a site with a score of 7–10; an average awarded for a score of 4–7 and poor was given to a site with a score of 0–4.

Results: For the U.K. search engines, twenty sites were evaluated and five common sites identified (spineuniverse.com, S.A.U.K.org, orthoteers.co.uk, B.O.A.ac. uk and scoilosis.info). From these sites only two were given a rating of good. For the World Wide Web search engines eighteen sites evaluated and seven common sites identified (SRS, spineuniverse.com, scoliosis.org, orthinfo.aaos.org, iscoliosis.com, scoliosisrx.com and scoliosis-world.com). From these sites four were given a rating of good. It was evident that the Scoliosis Association of United Kingdom did not appear in three of the search engines but only in Hotmail.

Conclusion: These results suggest that there are good sites available for patients to access information with regards to their condition and treatment options but there are also very poor sites available where incorrect information is available. Commonly, unfamiliar users of the Web will not search U.K. sites specifically and could easily miss the S.A.U.K. site, which is an excellent site and was one of the two sites via the U.K. search engine awarded a good score. Obviously, there were more good sites via the World Wide Web due to the American healthcare system. We recommend that leaflets should be available to parents and patients with scoliosis with information from the BSS of the condition and available Web sites with good ratings. Also we recommend that these sites be linked to the Royal College of General Practitioners Web site to provide reference on good practice.

Purpose: Chondroblastomas are a lesion of immature cartilage found in a typically epiphyseal location. The peak incidence is in teenagers. Current surgical treatment is a balance between complete excision, with potential for physeal and articular cartilage damage, and local recurrence. A minimally invasive technique with a low complication rate providing effective treatment may be provided by radiofrequency (RF) thermocoagulation. Already the treatment of choice for Osteoid Osteoma – another lesion that can occur in the epiphysis.1,2,3 Literature to date on clinical use of RF thermocoagulation in chondroblastoma is scarce.4 The high water content of chondroblastoma should ensure its sensitivity to RF ablation. Our units experience in osteoid osteoma has been extended to RF thermocoagulation of chondroblastoma.

Patients: Four patients were treated with RF thermocoagulation for a chondroblastoma. Minimum follow up one year.

Methods: A RITA Starburst probe thermocoagulates the lesion for at least 5 minutes at 90 degrees centigrade. Overnight stay and outpatient follow up until skeletal mature, or two years following treatment.

Results: Two chondroblastomas were in the proximal tibia, one in the distal femur and one in the proximal humerus. One patient had surgery previously and one patient presented with collapse of the proximal tibial plateau. All patients were treated successfully and are pain free. All patients, accepting the one with pre-existing collapse, have a full range of movement. There has been no local recurrence at one year.

Conclusion & Discussion: Our experience suggests that radiofrequency thermocoagulation is a safe and effective treatment method for patients with chondroblastoma.