Introduction. Hips following in-situ pinning for slipped capital femoral epiphysis (SCFE) have an altered morphology of the proximal femur with cam type deformity. This deformity can result in femoroacetabular impingement and early joint degeneration. The modified Dunn procedure allows to reorientate the slipped epiphysis to restore hip morphology and function. Objectives. To evaluate (1) hip pain and function, (2) 10-year survival rate and (3) subsequent surgeries and complications in hips undergoing modified Dunn procedure for SCFE. Methods. Between April 1998 and December 2005 we performed the modified Dunn procedure for 43 patients (43 hips) with SCFE. Twenty-five hips (58) presented with an acute or acute on chronic slip. The mean slip angle was 43° (range, 15° – 80°). A majority of 53% of procedures were performed in male patients and the mean age at operation was 13 years (10 – 19 years). We could followup all except one hip (followup of 5.5 year) for a minimum of 10 years (mean followup 13 [10 – 18 years]). We used the anterior impingement test to assess pain and the Merle d'Aubigné- ostel score to assess function. Survivorship calculation was performed using the method of Kaplan and Meier and any of the following factors as a definition of failure: radiographic evidence of worsening osteoarthritis (OA), or a Merle d'Aubigné-Postel score less than 15. Results. (1) The prevalence of a positive anterior impingement test decreased from 100% to 16% (p<0.001). The mean Merle d'Aubigné-Postel score improved from 13 (7 – 14) to 17 (14 – 18) at most recent followup (p<0.001). (2) Four hips (9%) showed progression of OA and three hips (7%) had a Merle d'Aubigné-Postel score of less than 15 at most recent followup. This resulted in a 93% survival rate at 10-year followup. (3) No hip developed avascular necrosis. Five hips (12%) had complications with reosteosynthesis due to screw breakage or nonunion. Another nine hips (21%) had subsequent surgeries including acetabular rim trimming / offset creation in 5 hips and screw removal in 4 hips. Conclusion. The modified Dunn procedure is a safe method to correct the morphology of the proximal femur in hips with SCFE. Ninety-free percent of the hips showed no progression of OA and a good clinical result at the 10-year followup. Twelve percent required revision surgery for complications all including screw breakage with nonunion of the greater trochanter

Introduction. To compare the union rates and post-operative mobility of antegrade intramedullary nailing of osteoporotic traumatic supracondylar femoral fractures (AO classification A to C2) with those of plating. Materials/Methods. We studied any traumatic intra or extra-articular supracondylar femoral fracture from 2005–2010. Patients were either admitted directly to our level 1 trauma centre or were referred from another hospital. Nineteen patients were identified, consisting of primarily fixation with five antegrade nails and fourteen plates. We defined osteoporotic bone as being present in anyone over sixty years old or who had a clinical diagnosis. One nail and six plates were excluded due to young age or fracture severity. This left four nails, six less invasive stabilisation system plates and two dynamic condylar screw plates. Both groups were comparable with respect to age, sex and AO fracture classification. Results. There was a significant difference in achieving union between the two groups (p=0.040). Union occurred within three months in all four fractures in the nail group but only three fractures (38%) united after primary fixation in the plate group. There were two failures due to screw pullout, one failure due to screw breakage, one broken plate after delayed-union and one screw breakage after non-union. The patients in the nail group had better mobility and less pain than the plate group but the difference was not statistically significant. Conclusion. We have shown that for patients with osteoporotic, supracondylar femoral fractures, fixation with an antegrade IM nail provides significantly better healing compared to plate fixation

Traditional procedures for orthopedic total joint replacements have relied upon bone cement to achieve long-term implant fixation. This remains the gold standard in number of procedures including TKR and PKR. In many cases however, implants fixed with cement have proven susceptible to aseptic loosening and 3. rd. body wear concerns. These issues have led to a shift away from cement fixation and towards devices that rely on the natural osteoconductive properties of bone and the ability of porous-coated implants to initiate on-growth and in-growth at the bone interface, leading to more reliable fixation. To facilitate long-term fixation through osseointegration, several mechanical means have been utilized as supplemental mechanism to aid in stabilizing the prostheses. These methods have included integrated keels and bone screws. The intent of these components is to limit implant movement and provide a stable environment for bone ingrowth to occur. Both methods have demonstrated limitations on safety and performance including bone fracture due keel induced stresses, loosening due to inconsistent pressfit of the keel, screw-thread stripping in cancellous bone, head-stripping, screw fracture, screw loosening, and screw pullout. An alternative method of fixation utilizing blade-based anchoring has been developed to overcome these limitations. The bladed-based fixation concept consists of a titanium alloy anchor with a “T-shaped” cross-section and sharped-leading end that can be impacted directly into bone. The profile is configured to have a bladed region on the horizontal crossbar of the “T” for engagement into bone and a solid rail at the other end to mates with a conforming slot on the primary body of the prosthesis. A biased chisel tip is added to the surface of the leading blade edge to draw the bone between the anchor's horizontal surface and surface of the implant, thus generating a compressive force at the bone-to-prothesis interface. The anchoring mechanism has been successfully been integrated into the tibial tray component of a partial knee replacement; an implant component that has a clinical history of revision due to loosening. A detailed investigation into the pulloff strength, wear debris generation, compressive-force properties, and susceptibility to tibial bone fracture was carried out on the anchor technology when integrated in a standard tibial tray of a partial knee replacement. When tested in rigid polyurethane bone foam (Sawbones, Grade 15) the pulloff strength of the construct increased by 360% when utilizing the anchor. The tibial tray and anchor construct were cycled under compressive loading and demonstrated no evidence of interface corrosion or wear debris generation after 1 million cycles. In addition, the anchor mechanism was shown to generate 340N of compressive force at the tibial tray-to-bone interface when evaluated with pressure sensitive film (Fuji Prescale, Medium Grade). Finally, the ultimate compressive load to induce tibial fracture was shown to increase by 17% for the anchored tray as compared to a traditional keeled tray when tested in an anatomic tibial sawbones model; and by 19% when evaluated in human cadaveric tibias. For any figures or tables, please contact authors directly

Additive manufacturing has enabled a radical change in how surgeons reconstruct massive acetabular defects in revision hip surgery. We report on the early clinical and radiological results from our methods for surgical planning, design, and implantation of 3D printed trabecular titanium implants in a cohort of patients with large unclassifiable pelvic defects. We set up a prospective investigation involving 7 consecutive patients. Inclusion criteria was the following: 1) A history of previous total hip replacement; and 2) Current imaging showing at least a Paprosky 3B defect. Planned acetabular inclination and version was 40° and 20° respectively. Post operatively all patients had a CT scan which was analysed with software to determine component position and compared to planned. Outpatient review was done at 2 weeks (For wound), 6 weeks (for weight bearing and fixation) and 52 weeks (for fixation and infection) post-operative. The median age at surgery was: 65 years (40–78). The median bone defect volume was 140cm. 3. Median surgery length was 5.2 hours (3–6.25). Median blood loss was 1300mL (450– 2000). Radiologically, components were stable and no screw breakages were identified. Achieved inclination was 41.0° (29.0–55.6) and achieved version was 15.8° (3.8–43.6). Median Oxford Hip score improved from 9 (2–44) to 25 (18–32). We have demonstrated a new series of pre, intra and post-operative methods for reconstruction of unclassifiable acetabular bony defects. Initial clinical and radiological results are excellent considering the severity of the bony defects. We recommend the use of our or similar methods when trying to reconstruct these defects

We identified 26 tibial tubercle osteotomies (TTOs) performed in 23 revision knee arthroplasties between 2009 and 2013. Average age at last operation was 66 (33–92). Mean follow-up period was 14 months (3–33). Eleven TTOs were performed in 10 knees for single stage revisions and 15 TTOs were performed in 13 knees for 2 stage revisions in the setting of deep infection. In this infected subset 11 patients had a TTO performed at the first stage. This osteotomy was left unfixed to avoid leaving metalwork in a potentially contaminated wound, reopened, and then definitively secured with screws at the second stage. Our technique involves fashioning a long 7×1cm tibial tuberosity osteotomy without a proximal step-cut. All osteotomies united with no fractures. Minor proximal migration was noted in one case associated with screw loosening. There was no proximal migration noted in the 2 stage cases where the osteotomy had been left initially unfixed. There were no extensor lags. We conclude that TTO is a safe and reproducible procedure when adequate exposure cannot be obtained in revision knee arthroplasty. In 2 stage revisions sequential osteotomies does not decrease union rates and leaving the osteotomy unfixed after the first stage does not cause any issues

Purpose:. To describe a plating technique for the Lapidus procedure as an alternative to the traditional screw fixation technique. To look at the complications experienced during the Lapidus procedure and to find possible solutions to prevent these complications. Methods:. A retrospective study of 34 Lapidus procedures in 26 patients (8 bilateral) between 2006 and 2009 was performed. All were done with a plating technique and a primary bone graft. The indications were:. metatarsus primus varus. hypermobility. degenerative TMT joint. Results:. The average intermetatarsal angle pre-operatively was 17.1° and this was reduced to 6,4° post – operatively. The complications experienced were:. post –operative metal removal = 6. transfer metatarsalgia = 1. hallux varus = 1. screw breakage = 1. delayed union = 1. non-union = 1. Conclusion:. The plating technique for the Lapidus procedure gives stable fixation and the outcome compares well with other methods of fixation

Introduction. Osteoporotic intertrochanteric fracture (ITF) is frequent injuries affecting elderly, osteoporotic patients leading to significant morbidity and mortality. Successful prognosis including union and alignment is challenging even though initial successful reduction with internal fixation. Although many factors are related to the patient's final prognosis. Well reduction with stable fracture fixation is still the goal of treatment to improve the quality of life and decrease morbidity in patients with hip fractures, but this in turn depends on the type of fracture and bone quality. Poor bone quality is responsible for common complications, such as failure of fixation, varus collapse and lag screw cut-out, in elderly patients. Kim et al. found that the complication rate when using conventional DHS in unstable ITFs can be as high as 50% because of screw cut-out. We used the dynamic hip screws (DHS) strengthened by calcium phosphate cement (CPC) for treatment femoral intertrochanteric fracture and review the prognosis of our patients. Materials and Methods. From January of 2011 to January of 2014, 42 patients with femoral intertrochanteric fracture underwent surgery with DHS strengthened by CPC. Comparisons were made between the DHS plus CPC group with the other patients with only DHS used in our department. All patients were followed up for an average time of 14.8(6 to 24) months. X-ray was reviewed for the conditions of union and implant failure. Results. In DHS group, fixation failure happened in 3 case, delayed union and coax varus deformity in 2 cases. IN DHS plus CPC group, all fractures healed uneventfully, there is no non-union or malunion in this group. There is only 1 fixation cut-out and 1 secondary lag screw sliding was noted, however, union was still well over fracture site in this case, the patient had no clinical symptoms. Discussion. Residual bony defects present after DHS fixation in intertrochanteric fracture may lead to postoperative complications, including nonunion or implant failure. DHS strengthened by CPC is reliable fixation for old patients with intertrochanteric fracture, We demonstrated that augmentation of the bony defect with dynamic hip screw by reinforced calcium phosphate cement significantly improved the strength of osteoporotic bone, prevent screw loosening, and promote early healing of fracture. The patients can be decreased the risk of refracture and allow early weight bearing, especially in elderly patients with osteoporotic bone

While reverse shoulder arthroplasty (RSA) is a reliable treatment option for patients with rotator cuff deficiency, loss of glenoid baseplate fixation often occurs due to screw loosening. We questioned whether an analysis of the trabecular bone density distribution in the scapula would indicate more optimal sites for screw placement. As such, the purpose of this study was to determine the anatomic distribution of trabecular bone density in regions of the scapula available for screw placement in RSA. Seven cadaveric shoulders were computed tomography (CT) scanned, and then voxels of the scapulae were isolated from the CT volume (Mimics 15.0 Materialise, Leuven, Belgium). Analyses were conducted in a common, 3D coordinate system. Volumetric regions of interest (ROI) within the scapula were identified based on potential baseplate screw sites. ROIs included areas at the base of the coracoid process lateral and inferior to the suprascapular notch, in the posterior and anterior lateral spine and in the anterosuperior and posteroinferior lateral border. Hounsfield Units (HU) were extracted from voxels corresponding to trabecular bone within each ROI. Overall bone density was summarised as the frequency of HU values above 80% of the ROI's maximum density value. Paired, two-tailed t-tests assuming unequal variance were used for pairwise comparisons (P≤0.05). Intra-region analyses compared two ROIs within the same broad anatomical structure; inter-region analyses compared ROIs between anatomical structures. Areas of the spine and lateral border of the scapula appeared to be denser than the coracoid process. Intra-region comparisons indicated no significant differences within ROI: coracoid P=0.43, spine P=0.95, lateral border P=0.41. ROI inferior to the suprascapular notch were on average 3.78% (P=0.08) and 6% (P=0.04) less dense than the anterosuperior and posteroinferior lateral border and 7.59% (P=0.006) and 7.72% (P=0.01) less dense than the anterior and posterior lateral spine. ROI lateral to the suprascapular notch were 6% (P=0.05) and 8.21% (P=0.02) less dense than the anterosuperior and posteroinferior lateral border and 9.8% (P=0.006) and 9.94% (P=0.008) less dense than the anterior and posterior lateral spine. There was no significant difference between the anterior spine and anterosuperior and posteroinferior lateral border (P=0.12, P=0.58), nor between the posterior spine and anterosuperior and posteroinferior lateral border (P=0.14, P=0.57). Results from this study indicate that the spine and lateral border of the scapula contain denser trabecular bone relative to regions in the coracoid. The higher quality bone of the spine and lateral border should be favoured over the coracoid process when fixing the glenoid baseplate in RSA. Further research may support the redesign of the glenoid baseplate geometry to better integrate the anatomy of the scapula and improve implant survival

Introduction. Distal femur fracture is a critical issue in orthopedic trauma, because it is difficult to manage especially in cases with intra-articular fracture. Osteoporosis may cause instability of implant and increase complications. Few studies investigate on the stability of distal femur osteoporotic fracture and the behaviors under cycling. Our hypothesis was that the stiffness of construct would decrease as cycling in osteoporotic bone. Materials and Methods. Seven cadaver specimens were used in this study. Relative bone density for each specimen was evaluated using CT scanning by three known calibration phantoms scanned simultaneously with the specimen. All cadaver specimens were divided normal (group 1) and osteoporosis (group 2) in accordance with the bone density. The titanium distal femur locking plates with 6 screws placed in distal femur condyle and 4 in shaft. A 10 mm gap with 65 mm proximal to the center of articular surface and a vertical fractural line between intra-articular were created to simulate AO C2 type fracture. Each specimen was cyclically loaded in two-phase at a frequency of 2 Hz. Phase 1 was set at 1000 N for 10000 cycles. In phase 2, the load was set at 2000 N for 10000 cycles. Then, the specimen was loaded up to failure at a rate of 5 mm/min. Stiffness was evaluated from the linear portion of load-displacement curve at 2000 cycle interval. Results and Discussion. Figure 1 showed the stiffness deterioration during cycling. Group 1 expresses the cadaveric specimen with normal bone density, and group 2 expresses osteoporosis. The stiffness of group 1 (with normal bone density) decreased for 26.2 % after 20000 cycles, however, group 2 (osteoporotic bone) revealed 90.3 % decay in stiffness. The stiffness decay observably when the load increased from 0 to 1000 N and from 1000 to 2000 N. The maximum load for group1 and group 2 were 4883±134 N and 2538 N, respectively. It can be found the normal bone density group showed intact circular hole, however, the osteoporotic bone revealed an oval contour. The subsidence of screws increased the risk of screw loosening and instability. It can be concluded that the bone quality and cyclic loading could be the important factors that affect the stability and failure strength of the construct

Introduction. Recently ventral plating implants made of carbon/PEEK composite material have been developed with apparently superior material properties in terms of implant fatigue and imaging suitability. In this study we assessed the outcome of the first clinical application of this new implant. Methods. Retrospective, single-center case series of 16 consecutive patients between 2011 and 2013 undergoing ventral stabilization surgery with a new carbon plating system (see figure 1). We collected data in terms of safety of the procedure (screw positioning, blood loss, operation time), quality and reliability of the implant (revisions, dislocations, screw loosening, fusion, adjacent segment degeneration), clinical outcome and biological tolerance (cervical pain / discomfort, dysphagia). Results. All patients were available for clinical and radiological follow up. Mean surgery time was 128 minutes, in 11 cases one in 5 cases 2 segments were treated. The clinical findings and patient's satisfaction were good in 14 and fair in two cases. All patients who completed the 6 months control had a radiographically confirmed interbody fusion; no implant loosening or failure and no infections were observed. (see figure 2). There was one implant related complication (dysphagia due to malpositioning of the plate which was removed 4 days after implant insertion) and one complication related to the approach (Horner's syndrome). Conclusion. In this retrospective study of 16 patients we found that the use of a carbon-composite plating system lead to results comparable to the “gold standard” metal plates in terms of safety / clinical outcome and reliability of the implant. There was one revision due to dysphagia. The MR imaging of the patients who have been operated with the carbon/PEEK system showed superior quality with reduced artifacts and improved diagnostical properties, especially when evaluating the neurogical structures. (see figure 3). The overall clinical outcome and patient acceptance of the implant was good. The radiologic findings on follow up of 2, 6 and 12 months have shown a high fatigue strength with no signs of implant failure in terms of dislocation, loosening or breakage. Therefore we conclude that the use of the carbon/PEEK plating system is suitable for ventral stabilization in trauma and degenerative disease

Background. Tension band epiphysiodesis for lower limb length discrepancy in children Planned physeal growth arrest (epiphysiodesis) for the treatment of limb length discrepancy (LLD) in growing children is a well described treatment modality in the literature. We describe our experience of temporary epiphysiodesis using a tension band technique with the “8-plate” in the treatment of LLD in growing children. Aim. The main objective of this study was to confirm whether bilateral 8-plates achieve an epiphysiodesis or not?. Methods and results. This is a prospective study of 27 patients who were treated with 8-plate epiphysiodesis for limb length discrepancy with a mean follow up of 28 months. Perthes disease was the most common underlying pathology for the LLD. The average preoperative LLD was 25.9 mm (15–49 mm). 17 patients successfully corrected to < 15 mm LLD, 5 patients corrected to between 15–20 mm and 5 patients did not correct to with in 15 mm LLD (22.2%). In those patients whom have corrected, the average correction length was 25.6 months with an average correction rate of 1.52 mm per month. There was a trend for insufficient equalisation if the procedure was performed < 1.5 years prior to skeletal maturity. The was also a trend for insufficient equalisation if performed at single physis only (femur or tibia). Complications included one superficial infection and one deep infection following plate removal at the end of treatment. Screw breakage was noticed in one patient. No long term complications were reported. No angular deformity was reported. Conclusion. This study has confirmed that bilateral 8 plates produce an epiphysiodesis. Failures are mainly due to late insertion or single physis usage. Future application depends on demonstrating reversibility when applied to younger children

Bioabsorbable screws for anterior cruciate ligament reconstruction (ACLR) have been shown to be associated with femoral tunnel widening and cyst formation. To compare a poly-L-lactide–hydroxyapatite screw (PLLA-HA) with a titanium screw with respect to clinical and radiological outcomes over a 5 year period. 40 patients were equally randomized into 2 groups (PLLA-HA vs titanium) and ACLR performed with a 4 strand hamstring graft with femoral tunnel drilling via the anteromedial portal. Evaluation at 2 and 5 years was performed using the International Knee Documentation Committee assessment (IKDC), Lysholm knee score, KT 1000 arthrometer, single-legged hop test. Magnetic resonance imaging was used to evaluate tunnel and screw volume, ossification around the screws, graft integration and cyst formation. There was no difference in any clinical outcome measure at 2 or 5 years between the 2 groups. At 2 years, the PLLA-HA femoral tunnel was significantly smaller than the titanium screw tunnel (p=0.015) and at 5 years, there was no difference. At 2 years the femoral PLLA-HA screw was a mean 76% of its original volume and by 5 years, 36%. At 2 years the tibial PLLA-HA screw mean volume was 68% of its original volume and by 5 years, 46%. At 5 years, 88% of femoral tunnels and 56% of tibial tunnels demonstrated a significant ossification response. There was no increase in cyst formation in the PLLA-HA group and no screw breakages. The PLLA-HA screw provides adequate aperture fixation in ACLR with excellent functional outcomes. It was not associated with femoral tunnel widening or increased cyst formation when compared with the titanium screw. The resorbtion characteristics appear favourable and the hydroxyapatite component of the screw may stimulate osteoconduction, contributing to these results. The PLLA-HA screw is a good alternative to a titanium screw in ACLR, which may aid revision procedures and allow for imaging without artifact

Purpose:. The purpose of the study was to evaluate the safety and efficacy of fixation of the lumbar spine, without fusion, using the Cosmic Pedicle Fixation System. Method:. Prospective study of 107 patients selected to have either a completely non fused fixation (40 patients), and 67 who underwent a hybrid fusion. During the same period 299 standard fusions were performed at same institution. Enrolment was from January 2006 to August 2008. Appropriate consent was obtained, but the choice of which levels to fuse and which levels to fix only was the surgeon's choice. Pre-operative ODI and VAS scores were obtained as well as parameters of sitting, standing and walking potential. Regular follow-up visits were done, and these parameters were controlled together with regular x-rays at each visit at 6 weeks, 6 months and 12 months and annually thereafter. Intra-operative blood loss, hospital stay and any adverse reaction or complications were documented. Results:. The average follow up was more than 3 years. Average age at surgery was 62 years. Most were treated for spinal stenosis (79/107). Average VAS score improved from 8 to 2.2. ODI score improved from 50 to 14 (at 12 months), but there was a slight deterioration with time and aging. All improved dramatically on walking distances and sitting time. Revision surgery was required in 10 patients, of which only 5 had fusions performed at the previously non fused segment. Screw breakage occurred in a number of patients but was not correlated to poor outcomes. Average blood loss was 336 ml while hospital stay was only 3 days. Conclusion:. Cosmic fixation without fusion is safe, giving comparable results to fusion with less complications, shorter hospital stay and very modest blood loss. Although not measured as such, pain control and use of opioids were deemed much less than conventional fusion surgery

Various operative treatments have been proposed for proximal humeral fractures. The purpose of our study was to compare complications of plate versus nail for these proximal humeral fractures and to determine whether it is the implant or fracture and surgeon related factors which result in complications. We had 74 patients operated from March 2006 till June 2008 for displaced 3 (49pts) or 4 (25pts) part proximal humeral fractures. 43 had plating (PHILOS) and 31 had a humeral nail inserted. 57 patients were over 60 years at presentation while 17 were younger than 60. All patients were followed regularly radiologically. The functional outcomes were assessed by Quick DASH score and were comparable in both groups at 1 year postoperatively.18 of the 43 patients in the Plating group had a radiological complication with 9 cases of screw cut-out, 5 fractures maluniting and 1 nonunion. There was no case of osteonecrosis. In the nailing group, 13 patients had radiological complications, with 8 patients having varus malunion, 3 having proximal screw loosening and 1 having osteonecrosis apart from the clinical complications of impingement and rotator cuff problems. Given the similar complication rate and similar functional outcome achieved by both these techniques it is hard to determine if any one in particular is better than the other. The key determining factors for a proximal humeral fracture might actually be patient and surgeon related. It is important to achieve medial continuity and good initial reduction in these fractures to prevent them from collapsing into varus, especially with the nails. Also, patient age, osteoporosis and functional demand are factors determining success of surgery in these patients. We did not find the severity of the fracture to be a determining factor, maybe this was because the relative proportion of type 4 fractures in our series was less

To elucidate the molecular biology of fracture healing, murine models are preferred. We performed a study with the first internal fixation system that allows studying murine fracture healing in a controlled mechanical environment, to characterise the timing of the fracture healing cascade with this model, based on a histological evaluation. Femoral osteotomies were performed in 68 male C57BL/six mice and stabilised with locking internal fixation plates in either stiff, or defined, flexible configurations. Healing progression was studied at 10 time points between 3 and 42 days post- surgery. After surgery, mice were radiographed to confirm the correct implant positioning. After sacrifice, the extracted femora were processed for decalcified histology. Thin sections were taken as serial transverse sections and stained for subsequent histomorphometric analysis and three-dimensional reconstruction of the different fracture callus tissues. The surgery was successful in 62 animals. Only six6 (8.8%) animals had to be sacrificed due to complications during surgery. The post-operative radiographs demonstrated a high reproducibility of implant positioning and no implant failure or screw loosening occurred during the experimental period. The improved consistency in surgical technique leading to more uniform results represents a key advantage of this system over other mouse fracture healing models. As such, it may allow a reduction in the sample size needed in future murine fracture healing studies. The histological evaluation confirmed the lack of a periosteal callus, and exclusively endosteal, intramembraneous bone formation in the bones stabilised with the stiff implants. The bones that were stabilised with the more flexible internal fixation plates showed additional endochondral ossification with extensive, highly asymmetrical, periosteal callus formation. Our results demonstrate that this murine fracture model leads to different healing patterns depending on the flexibility of the chosen plate system. This allows researchers to investigate the molecular biology of fracture healing in different ossification modes by selection of the appropriate fixation

Percutaneous cannulated screw placement (PCSP) is a common method of fixation. In pelvic trauma neurovascular structures are in close proximity to the screw path. Pre-operative planning is needed to prevent injury. This study aims to the safety margin and accuracy of screw placement with computer navigation (CAS). A control had no pathology in the pelvis but CT scans were performed for suspected trauma. The treated group had pelvic and acetabular fractures and were treated with CAS PCSP at our institution. Using a new technique involving CT 3D modelling of the whole (3D) safe corridor, the dimensions of the Posterior elements (PE) of the pelvic ring and the anterior column of the acetabulum (AC) were measured in the control group. The accuracy of screw placement (deviation between the actual screw and planned screw) was measured in treated patient using a screenshot method and post-operative CTs. There were 22 control patients and 30 treated patients (40 screws). The mean ± (standard deviation, SD) minimum measurement of the safe corridor at the PE was 15.6 ± 2.3 mm (range 11.6 mm to 20.2 mm) and at the AC was 5.9 ±1.6 mm (range 3.0 mm to 10.0 mm). The mean ± (SD) accuracy of screw placement was 6.1 ± 5.3 mm and ranged from a displacement of 1.3 mm to 16.1 mm. There was a notable correlation between Body Mass Index, duration of surgery and inaccuracy of screw placement in some patients. The largest inaccuracy of screw placement was due to reduction of the fracture during screw insertion, causing movement of the bone fragments relative to the array and therefore also the computerised screw plan. There were no screw breakages, non-unions, neurological or vascular complications. CAS PCSP is a safe and accurate technique. However, the safe corridor is variable and often very narrow. We recommend that the dimensions of the safe corridor be assessed pre-operatively in every patient using 3D modelling to determine the number and size of screw that can be safely placed

Introduction. Anterior reconstruction has the advantage of conferring immediate stability to the cervico-thoracic junction. Aims and objectives. Assess clinical and radiological outcome in cervico-thoracic kyphosis treated with anterior reconstruction. Material and methods. 62 cases were treated with anterior reconstruction from 1996-2007. Minimum follow-up was 2years (2-6). Indications included tuberculosis (45), dysplastic(10), neoplastic (3) and traumatic (4). Average age was 28.6 years (13-72 years). Average pre-operative kyphosis was 26.4 degrees (5-84). Patients were grouped as long-neck (35) and short-neck (27) according to classification proposed by Bapat and Laheri. The caudal normal vertebra (CNV) matched on plain radiology and MRI in 40 (64.51%). In 22 level of fixation was extended due to poor bone mass in the adjacent vertebral body (caudal 17, cranial 5). Pre-operative neurological deficit was seen in 57 (91.3%) and average Nurick's grade was 3.8 (0-5). Results. 32 long-neck patients required strap-muscle tenotomy to expose the CNV. In 3(9.3%) manubriotomy was required (large neck girth 1, thyroid goitre 2). 26 short-neck patients required manubriotomy for plate placement. In 42 (67.8%) patients a standard anterior cervical plate was used. In 22 locking plate was used. Commonest cranial and caudal vertebrae instrumented were C7 (32) and T2 (20) respectively. Post-operative kyphosis averaged 14.68 degrees (0-78) and correction averaged 11.72 degrees. Average post-operative Nurick's grade was 2.8. One patient with fracture dislocation of T1-T2 and traumatic oesophageal rupture died. In 1 the implant loosened and was revised with posterior construct. In 1, screw loosening was observed but implant position remained unaltered. 2 patients had recurrent laryngeal palsy. Iatrogenic pleural rent occurred in 2 patients. Transient dysphagia was noticed in 12. The scar hypertrophy was seen in 30(48.38%). The loss of correction averaged 2.3mm (0-4mm) at the final follow-up. Conclusion. Anterior reconstruction allows excellent reconstruction of cervico-thoracic junction obviating need for a posterior construct

Reverse shoulder arthroplasty has a high complication rate related to glenoid implant instability and screw loosening. Better radiographic post-operative evaluation may help in understanding complications causes. Medical radiographic imaging is the conventional technique for post-operative component placement analysis. Studies suggest that volumetric CT is better than use of CT slices or conventional radiographs. Currently, post-operative CT use is limited by metal-artifacts in images. This study evaluated inter-observer reliability of pre-operative and post-operative CT images registration to conventional approaches using radiographs and CT slices in measuring reverse shoulder arthroplasty glenoid implant and screw percentage in bone. Pre-operative and post-operative CT scans, and post-operative radiographs were obtained from six patients that had reverse shoulder arthroplasty. CT scans images were imported into a medical imaging processing software and each scapula, glenoid implant and inferior screw were reconstructed as 3D models. Post-operative 3D models were imported into the pre-operative reference frame and matched to the pre-operative scapula model using a paired-point and a surface registration. Measurements on registered CT models were done in reference to the pre-operative scapula model coordinate frame defined by a computer-assisted designed triad positioned in respect to the center of the glenoid fossa and trigonum scapulae (medial-lateral, z axis) and superior and inferior glenoid tubercle (superior-inferior, y axis). The orthogonal triad third axis defined the anterior-posterior axis (x axis). A duplicate triad was positioned along the central axis of the glenoid implant model. Using a virtual protractor, the glenoid implant inclination was measured from its central axis and the scapula transverse plane (x - z axes) and version from the coronal plane (y - z axes). Inferior screw percentage in bone was measured from a Boolean intersection operation between the pre-operative scapula model and the inferior screw model. For CT slices and radiographic measurements, a first 90-degree Cobb angle, from medical records software, was positioned from the trigonum scapulae to the centre of the central peg. Using the 90-degree line as reference, a second Cobb angle was drawn from the most superior to the most inferior point of the glenoid implant for inclination and from of the most anterior to the most posterior point for version. Version can only be measured using CT slices. Screw percentage in bone was calculated from screw length measures collected with a distance-measuring tool from the software. For testing the inter-observer reliability of the three methods, measures taken by three qualified observers were analysed using an intra-class correlation coefficient (ICC) method. The 3D registration method showed excellent reliability (ICC > 0.75) in glenoid implant inclination (0.97), version (0.98) and screw volume in bone (0.99). Conventional methods showed poor reliability (ICC < 0.4); CT-slice inclination (0.02), version (0.07), percentage of screw in bone (0.02) and for radiographic inclination (0.05) and percentage screw in bone (0.05). This CT registration of post-operative to pre-operative novel method for quantitatively assessing reverse shoulder arthroplasty glenoid implant positioning and screw percentage in bone, showed excellent inter-observer reliability compared to conventional 2D approaches. It overcomes metal-artifact limitations of post-operative CT evaluation