Aims

Proximal humeral fractures are the third most common fracture among the elderly. Complications associated with fixation include screw perforation, varus collapse, and avascular necrosis of the humeral head. To address these challenges, various augmentation techniques to increase medial column support have been developed. There are currently no recent studies that definitively establish the superiority of augmented fixation over non-augmented implants in the surgical treatment of proximal humeral fractures. The aim of this systematic review and meta-analysis was to compare the outcomes of patients who underwent locking-plate fixation with cement augmentation or bone-graft augmentation versus those who underwent locking-plate fixation without augmentation for proximal humeral fractures.

Proximal humeral shaft fractures are commonly treated with long straight locking plates endangering the radial nerve distally. The aim of this study was to investigate the biomechanical competence in a human cadaveric bone model of 90°-helical PHILOS plates versus conventional straight PHILOS plates in proximal third comminuted humeral shaft fractures. Eight pairs of humeral cadaveric humeri were instrumented using either a long 90°-helical plate (group1) or a straight long PHILOS plate (group2). An unstable proximal humeral shaft fracture was simulated by means of an osteotomy maintaining a gap of 5cm. All specimens were tested under quasi-static loading in axial compression, internal and external rotation as well as bending in 4 directions. Subsequently, progressively increasing internal rotational loading until failure was applied and interfragmentary movements were monitored by means of optical motion tracking. Flexion/extension deformation (°) in group1 was (2.00±1.77) and (0.88±1.12) in group2, p=0.003. Varus/valgus deformation (°) was (6.14±1.58) in group1 and (6.16±0.73) in group2, p=0.976. Shear (mm) and displacement (°) under torsional load were (1.40±0.63 and 8.96±0.46) in group1 and (1.12±0.61 and 9.02±0.48) in group2, p≥0.390. However, during cyclic testing shear and torsional displacements and torsion were both significantly higher in group 1, p≤0.038. Cycles to catastrophic failure were (9960±1967) in group1 and (9234±1566) in group2, p=0.24. Although 90°-helical plating was associated with improved resistance against varus/valgus deformation, it demonstrated lower resistance to flexion/extension and internal rotation as well as higher flexion/extension, torsional and shear movements compared to straight plates. From a biomechanical perspective, 90°-helical plates performed inferior compared to straight plates and alternative helical plate designs with lower twist should be investigated in future paired cadaveric studies

To date, the fixation of proximal humeral fractures with angular stable locking plates is still insufficient with mechanical failure rates of 18% to 35%. The PHILOS plate (DePuy Synthes, Switzerland) is one of the most used implants. However, this plate has not been demonstrated to be optimal; the closely symmetric plate design and the largely heterogeneous bone mineral density (BMD) distribution of the humeral head suggest that the primary implant stability may be improved by optimizing the screw orientations. Finite element (FE) analysis allows testing of various implant configurations repeatedly to find the optimal design. The aim of this study was to evaluate whether computational optimization of the orientation of the PHILOS plate locking screws using a validated FE methodology can improve the predicted primary implant stability. The FE models of nineteen low-density (humeral head BMD range: 73.5 – 139.5 mg/cm3) left proximal humeri of 10 male and 9 female elderly donors (mean ± SD age: 83 ± 8.8 years) were created from high-resolution peripheral computer tomography images (XtremeCT, Scanco Medical, Switzerland), using a previously developed and validated computational osteosynthesis framework. To simulate an unstable mal-reduced 3-part fracture (AO/OTA 11-B3.2), the samples were virtually osteotomized and fixed with the PHILOS plate, using six proximal screws (rows A, B and E) according to the surgical guide. Three physiological loading modes with forces taken from musculoskeletal models (AnyBody, AnyBody Technology A/S, Denmark) were applied. The FE analyses were performed with Abaqus/Standard (Simulia, USA). The average principal compressive strain was evaluated in cylindrical bone regions around the screw tips; since this parameter was shown to be correlated with the experimental number of cycles to screw cut-out failure (R2 = 0.90). In a parametric analysis, the orientation of each of the six proximal screws was varied by steps of 5 in a 5×5 grid, while keeping the screw head positions constant. Unfeasible configurations were discarded. 5280 simulations were performed by repeating the procedure for each sample and loading case. The best screw configuration was defined as the one achieving the largest overall reduction in peri-screw bone strain in comparison with the PHILOS plate. With the final optimized configuration, the angle of each screw could be improved, exhibiting significantly smaller average bone strain around the screw tips (range of reduction: 0.4% – 38.3%, mean ± SD: 18.49% ± 9.56%). The used simulation approach may help to improve the fixation of complex proximal humerus fractures, especially for the target populations of patients at high risk of failure

Aims

Fixation of osteoporotic proximal humerus fractures remains challenging even with state-of-the-art locking plates. Despite the demonstrated biomechanical benefit of screw tip augmentation with bone cement, the clinical findings have remained unclear, potentially as the optimal augmentation combinations are unknown. The aim of this study was to systematically evaluate the biomechanical benefits of the augmentation options in a humeral locking plate using finite element analysis (FEA).

Proximal humeral fractures occur frequently, with fixed angle locking plates often being used for their treatment. However, the failure rate of this fixation is high, ranging between 10 and 35%. Numerous variables are thought to affect the performance of the fixation used, including the length and configuration of screws used and the plate position. However, there is currently limited quantitative evidence to support concepts for optimal fixation. The variations in surgical techniques and human anatomy make biomechanical testing prohibitive for such investigations. Therefore, a finite element osteosynthesis test kit has been developed and validated - SystemFix. The aim of this study was to quantify the effect of variations in screw length, configuration and plate position on predicted failure risk of PHILOS plate fixation for unstable proximal humerus fractures using the test kit. Twenty-six low-density humerus models were selected and osteotomized to create a malreduced unstable three-part fracture AO/OTA 11-B3.2 with medial comminution which was virtually fixed with the PHILOS plate. In turn, four different screw lengths, twelve different screw configurations and five plate positions were simulated. Each time, three physiological loading cases were modelled, with an established finite element analysis methodology utilized to evaluate average peri-screw bone strain, this measure has been previously demonstrated to predict experimental fatigue fixation failure. All three core variables lead to significant differences in peri-screw strain magnitudes, i.e. predicted failure risk. With screw length, shortening of 4 mm in all screw lengths (the distance of the screw tips to the joint surface increasing from 4 mm to 8 mm) significantly (p < 0 .001) increased the risk of failure. In the lowest density bone, every additional screw reduced failure risk compared to the four-screw construct, whereas in more dense bone, once the sixth screw was inserted, no further significant benefit was seen (p=0.40). Screw configurations not including calcar screws, also demonstrated significant (p < 0 .001) increased risk of failure. Finally, more proximal plate positioning, compared to the suggested operative technique, was associated with reduced the predicted failure risk, especially in constructs using calcar screws, and distal positioning increased failure risk. Optimal fixation constructs were found when placing screws 4 mm from the joint surface, in configurations including calcar screws, in plates located more proximally, as these factors were associated with the greatest reduction in predicted fixation failure in 3-part unstable proximal humeral fractures. These results may help to provide practical recommendations on the implant usage for improved primary implant stability and may lead to better healing outcomes for osteoporotic proximal fracture patients. Whilst prospective clinical confirmation is required, using this validated computational tool kit enables the discovery of findings otherwise hidden by the variation and prohibitive costs of appropriately powered biomechanical studies using human samples

Aims

The aim of this study was to describe the technique of distraction osteogenesis followed by arthrodesis using internal fixation to manage complex conditions of the ankle, and to present the results of this technique.

Aims. Plating displaced proximal humeral fractures is associated with a high rate of screw perforation. Dynamization of the proximal screws might prevent these complications. The aim of this study was to develop and evaluate a new gliding screw concept for plating proximal humeral fractures biomechanically. Methods. Eight pairs of three-part humeral fractures were randomly assigned for pairwise instrumentation using either a prototype gliding plate or a standard PHILOS plate, and four pairs were fixed using the gliding plate with bone cement augmentation of its proximal screws. The specimens were cyclically tested under progressively increasing loading until perforation of a screw. Telescoping of a screw, varus tilting and screw migration were recorded using optical motion tracking. Results. Mean initial stiffness (N/mm) was 581.3 (. sd. 239.7) for the gliding plate, 631.5 (. sd. 160.0) for the PHILOS and 440.2 (. sd. 97.6) for the gliding augmented plate without significant differences between the groups (p = 0.11). Mean varus tilting (°) after 7500 cycles was comparable between the gliding plate (2.6; . sd. 1.9), PHILOS (1.2; . sd. 0.6) and gliding augmented plate (1.7; . sd. 0.9) (p = 0.10). Similarly, mean screw migration(mm) after 7500 cycles was similar between the gliding plate (3.02; . sd. 2.85), PHILOS (1.30; . sd. 0.44) and gliding augmented plate (2.83; . sd. 1.18) (p = 0.13). Mean number of cycles until failure with 5° varus tilting were 12702 (. sd. 3687) for the gliding plate, 13948 (. sd. 1295) for PHILOS and 13189 (. sd. 2647) for the gliding augmented plate without significant differences between the groups (p = 0.66). Conclusion. Biomechanically, plate fixation using a new gliding screw technology did not show considerable advantages in comparison with fixation using a standard PHILOS plate. Based on the finding of telescoping of screws, however, it may represent a valid approach for further investigations into how to avoid the cut-out of screws. Cite this article: Y. P. Acklin, I. Zderic, J. A. Inzana, S. Grechenig, R. Schwyn, R. G. Richards, B. Gueorguiev. Biomechanical evaluation of a new gliding screw concept for the fixation of proximal humeral fractures. Bone Joint Res 2018;7:422–429. DOI: 10.1302/2046-3758.76.BJR-2017-0356.R1

Background. Osteoporotic fracture fixation in the proximal humerus remains a critical challenge. While the biomechanical benefits of screw augmentation with bone cement are established, minimising the cement volume may help control any risk of extravasation and reduce surgical procedure time. Previous experimental studies suggest that it may be sufficient to only augment the screws at the sites of the lowest bone quality. However, adequately testing this hypothesis in vitro is not feasible. Methods. This study systematically evaluated the 64 possible strategies for augmenting six screws in the humeral head through finite element simulations to determine the relative biomechanical benefits of each augmentation strategy. Two subjects with varying levels of local bone mineral density were each modeled with a 2-part and 3-part fracture that was stabilised with a PHILOS plate. The biomechanical fixation was evaluated under physiological loads (muscle and joint reaction forces) that correspond to three different motions: 45 degrees abduction, 45 degrees abduction with 45 degrees internal rotation, and 45 degrees flexion. Results. The higher risk cases (low bone quality or 3-part fracture) exhibited greater peri-implant bone strains and derived greater benefits from screw augmentation. When selecting four screws to augment, the biomechanical benefits ranged from a 25% reduction in bone strain to a 59% reduction in bone strain, depending on the choice of screws. Further, the relative benefits of each augmentation strategy varied between patients and under different loading conditions. Correlations between local bone mineral density and benefits of augmentation were not significant. Conclusions. An optimal augmentation strategy is likely patient-specific and a larger cohort, modeled under a variety of conditions, would be required to elucidate any patient-specific factors (e.g. morphology or bone quality) that may dictate the relative benefits of each augmentation strategy

Aims

A pragmatic multicentre randomised controlled trial (PROFHER) was conducted in United Kingdom National Health Service (NHS) hospitals to evaluate the clinical effectiveness and cost effectiveness of surgery compared with non-surgical treatment for displaced fractures of the proximal humerus involving the surgical neck in adults.

Contoured locking plates are commonly used to fix the proximal humerus fractures. Their long-term results are unknown. We present long-term radiological and functional outcome of three and four part fractures of the proximal humerus treated with PHILOS plate. We prospectively analysed 53 consecutive three and four part proximal humerus fractures treated with PHILOS plate between 2002 and 2007. Patients were assessed using Oxford Shoulder Score and DASH score. 44 fractures (21 three part and 23 four part) were available at the final follow up. At a mean follow-up of 8.5 years (6.4 years–10.8 years) the average Oxford Shoulder Score was 43.9 (range 23–48) and the average DASH score was 7.7 (range 0–36.7). 30% of patients required re-operation (five for hemiarthroplasty, three for impingement syndrome, five for removal of implant). Avascular necrosis (AVN) developed in 10 patients, of which only three required hemiarthroplasty. All except one patient were satisfied with the result of their operation. Our study supports the use of locking plates for the treatment of three and four part proximal humeral fractures. In spite of some patients requiring secondary surgical intervention in the first few years, the function of the shoulder continues to improve and in the long term patients were satisfied with the outcome. An important finding of our study is that the post-traumatic AVN of humeral head does not necessarily need major surgical intervention. We believe that the possibility of avascular necrosis should not be a major determinant in the choice of surgical treatment of proximal humeral fractures

The purpose of this study is to describe the use of the PHILOS plate (Synthes) in reverse configuration to treat complex distal humeral non-unions. Non-union is a frequent complication of distal humeral fracture. It is a challenging problem due to the complex anatomy of the distal humerus, small distal fragment heavily loaded by the forearm acting as a long lever arm with powerful forces increasing the chances of displacement. Rigid fixation and stability with a device of high “pull-out” strength is required. The PHILOS plate has been used in reverse configuration to achieve good fixation while allowing central posterior placement of the implant. 11 patients with established non-union of distal humeral fractures were included in this study. No patient in whom this implant was used has been excluded. Initial fixation was revised using the PHILOS plate in reverse configuration and good fixation was achieved. Bone graft substitutes were used in all cases. Patients were followed to bony union, and functional recovery. All fractures united. One required revision of plate due to fatigue failure. Average time to union was 8 months with excellent restoration of elbow function. A reversed PHILOS plate provides an excellent method of fixation in distal humeral non-union, often complicated by distorted anatomy and previous surgical intervention. It has a high “pull-out” strength and may be placed in the centre of the posterior humerus, allowing proximal extension of the fixation as far as is required. It provides secure distal fixation without impinging on the olecranon fossa. It is more versatile and easier to use than available pre contoured plating systems

We present a novel use for an adult proximal humeral locking plate. In our case an 18-year-old female with cerebral palsy sustained a peri-prosthetic fracture of a blade plate previously inserted for a femoral osteotomy. Treatment was revision using a long proximal humeral locking plate. She had a successful outcome. We present the history and operative management. The female had a history of quadriplegic cerebral palsy, asthma, diabetes mellitus and congenital heart disease. She had a gastrostomy tube for enteral feeding. She was on nutritional supplements, baclofen, Omeprazole and movicol. She is looked after by her parents and requires a wheelchair for mobility. She is unable to communicate. Surgical History: Right adductor tenotomy, aged 11. Femoral Derotation Osteotomy & Dega Acetabular Osteotomy, aged 13. Right distal hamstring and knee capsule release, aged 14. Admitted to A&E (aged 18); unwitnessed fall. Painful, swollen, deformed thigh with crepitus. Xrays demonstrated peri- prosthetic fracture below blade plate. No specific equipment available to revise. Decision made to use PHILOS (Synthes, UK). GA, antibiotics, supine on table. Lateral approach. Plate removed after excising overgrown bone. Reduced and held. 10hole PHILOS applied. Near anatomical reduction. Secure fixation with locking screws proximally away from blade plate defect. Blood loss 800ml. 5 days in hospital. Sequential fracture clinic review. Wound healed well. Fracture healed on Xray at 11 months and discharged. To our knowledge this is the first reported use of a PHILOS plate for this specific fracture. The complexity of this case and underlying neurological disorder deemed long blade plate revision unsuitable. Fracture rates after femoral derotation osteotomies rare. 5/157 and 1/58 in the two largest studies to date. Conservative measures were the main recommendation. We have demonstrated a straightforward method for revision fixation with an excellent outcome. It would be recommended as an alternative to other surgeons in this position

Displaced proximal Humeral fractures at Inverclyde Royal Hospital prior to 2008 were previously treated with the antegrade Acumed Polaris Proximal Humeral, predominantly in 2 part fractures. The Philos plate was introduced in 2008, initially being used to treat select non unions, and then expanded to acute fractures. The aim of this study was to assess time to union and complications in the lower volume District General setting comparing to published outcomes. From February 2008 – January 2011, 20 patients were identified. Age range 49–75 (mean 61.2) years, 8 male; 12 female. Left 9, Right 11 Neers 2 part 35%; 3 35%; 4 30%. 16 (80%) were performed in acute fractures with 4 for non-unions, 3 of which were previous polaris nail fixations. 2 patients were lost to follow up after 6/52 but were progressing well. Union was confirmed radiologically and clinically in all but 2 remaining patients (10%), one of whom suffered a significant complication of plate fracture, the second treated with revision for painful non union. 2 other significant complications were observed: transient axillary nerve palsy and deep infection. Both of these patients recovered with delayed union observed in the infection case (52 weeks). Time to union range was 8–52 weeks (mean 17.1). The literature shows a high failure rate of up to 45% with intramedullary nail fixation and limited predominantly to 2 part fractures with risk of damage to the rotator cuff. This study shows a satisfactory union rate using the Philos of 90% with only 3 (15%) requiring further surgery for non-union, plate fracture and infection. 3 and 4 part fractures composed 65% of case load. Early results indicate satisfactory outcomes compared to current published literature

There is continued concern over complication rates (20–30% of cases) in locked proximal humeral plating. The most common sequelae of this is screw penetration of the humeral head. This is associated with natural settling of the fracture, malreducition in varus, insufficent medial support of the fracture. The proximity of the screws to the articular surface can also be influential on outcome if collapse occurs. Our operative technique is to establish the rotation of the humeral head where the drill appears closest to the articular margin (by sequential xray screening) and subtract from this to avoid intra-articular penetration of the humeral head. 55 Consecutive patients of average age 56.4 years (14.7–86.1), 17 male and 38 females, who underwent PHILOS plating were identified using Bluespier database. Xrays were analysed for fracture pattern, restoration of neck-shaft angle, plate positioning, number and configuration of screws and presence of screw penetration both intra-operatively and at postoperative follow-up. There were 6.07 screws used per head (total 330). There was one intraoperative screw penetration and 3 patients had evidence of screw penetration at follow-up, which required implant removal (total screw penetration rate of 7%). There was one case of AVN. The mean neck shaft angle was 137 degrees (anatomical 135 degrees). Accurate reduction of fractures and placement of screws in the humeral head using image intensifier can act to minimise risk of screw penetration and make some of the complications of locked proximal humeral plating avoidable

Introduction. Proximal humeral shaft fractures are rare injury. In such case, to the best of our knowledge, the treatment by both double-plate method and the MIPO has never been seen before in the literature. Here we report our experience and management about this method. Materials & Methods. A 69-year-old man who suffered falling down at home to his right shoulder that resulted in co-existing fractures of the proximal humerus and humeral shaft. According to AO/ASIF classification, he had 11-B1 and 12-A1 fractures ipsilaterally. He was treated by double plate method with PHILOS (SYNTHES, Japan) to proximal humerus and narrow LC-LCP(SYNTHES, Japan) to humeral shaft. Intraoperatively we put the skin incision about 3.0 cm each in three places, for reduction and fixation by the MIPO. Postoperatively, external fixation was only sling and physiotherapy was initiated after third post-operative days for range of motion exercises. Results. Union was achieved after 3.0 months and, at follow-up 1 year after injury, he had no pain and a good range of shoulder movement. Constant-Murley score was 90 points. Also he had no complication such as avascular necrosis and implant failure. Discussion & Conclusion. In this case, less invasive and rigid fixation by this method could result in early mobilization of the shoulder, relatively early union and a good functional outcome. Double-plate method with the MIPO might be one valid option in the treatment of proximal humeral shaft fractures

The aim of the study was to assess the medium term outcome for complex proximal humeral fractures treated with the long proximal humeral internal locking system (PHILOS) plate fixation. All patients who had long PHILOS plate fixation of proximal humerus fractures with metaphyseal or diaphyseal extension over a three year period at our institution were included in the study. Patients had their case notes and radiographs reviewed. Patients were also contacted to assess functional outcome using the Visual Analogue Scale (VAS) for pain, DASH, Oxford shoulder score (OSS) and Stanmore Percentage of Normal Shoulder Assessment (SPONSA). Out of an initial cohort of 34 patients, 1 died, 2 patients had unrelated illnesses resulting in them being unable to complete the assessment and 6 were lost to follow-up, leaving 25 patients (74%) for review. All patients had proximal humeral fractures with metaphyseal or diaphyseal extension requiring long plate osteosynthesis. One patient had the procedure for non union following initial treatment with an intra medullary nail and the rest were acute injuries. The patients were followed up after a mean of 27 months (range 11–60). The length of plate used varied from 5 to 12 holes for the shaft region. There was 1 wound infection. 3 patients had non unions which required bone grafting and revision internal fixation. At final follow-up, mean pain was 3.6 (95% Confidence Interval 2.5–4.8) with only 4 patients having residual pain greater than 5 on the VAS scale. Mean DASH score was 41.2 (95% CI 32.0–50.4), mean OSS was 29.1 (95% CI 24.3–33.9) and mean SPONSA was 63.9% (95% CI 50.8–77.2). The long PHILOS plate appears to represent a good treatment option for complex proximal humerus fractures with favourable medium term results and few complications

Patients using a neutral rotation brace post proximal humerus fracture fixation have improved functional outcome and external rotation of the shoulder compared to patients using a standard polysling. Patients who have proximal humerus fracture fixation with extramedullary plates and screws have a risk of reduced range of movement especially external rotation. Gerber et al showed that the average external rotation after fixation of proximal humeral fractures was 39 degrees in their patient cohort compared to a normal range of 80–100 degrees. This can lead to reduced function and poor patient related outcomes. Geiger et al showed that in a cohort of 28 patients, poor functional outcome was noted in 39.3% with an average Constant-Murley Score of 57.9. Current practice is to utilise a polysling holding the shoulder in internal rotation post-shoulder fixation. Patients usually wear the sling for up to 6 weeks. We believe that this increases the risk of adhesion formation with the shoulder in internal rotation in the shoulder joint. Therefore this can cause loss of external rotation in the shoulder joint. We believe that holding the shoulder in a neutral alignment, with a neutral rotation brace post-fixation, will enable an increased rate of external rotation post-operatively thus improving external rotation and functional outcome. There is currently no literature comparing the different slings used post-operatively and we believe that this study would be the first of its kind. It would have a substantial change in the way clinicians manage proximal humeral fractures and will potentially reduce the numbers of re-operations to divide adhesions or perform capsular releases. Secondary benefits include a potential earlier return to full function and work and improved patient satisfaction. Study proposal: Prospective Randomised Controlled Trial of the neutral rotation brace compared to the standard, currently used, polysling post proximal humerus fracture fixation. No blinding of either participants or clinicians. Three surgeons utilising similar fixation techniques via the deltopectoral approach and using Philos plate fixation (Synthes Ltd.). Standardised post-operative rehabilitation protocol for all patients. Follow up: clinical review and postal outcomes for 1 year. Primary outcomes: Post operative functional outcome scores (Oxford, DASH, EQL) obtained at 6 weeks, 9 weeks, 3 months and 1 year). These will be compared to scores taken pre-operatively. Secondary outcomes: Clinical review at 6 weeks, 3 months and 1 year with range of movement measurements. Radiographs also taken at 6 weeks and 3 months to assess union. Patient questionnaire at 1 year (with outcome scores) assessing patient return to work, complications and patient satisfaction. Inclusion criteria: Proximal humeral fractures requiring operative intervention with extramedullary plate fixation (i.e. fractures displaced by 1cm and/or angulated by 45 degrees or more). Age>18. Exclusion Criteria: Patients having intra-operative findings of complete Pectoralis major rupture or if operative exposure requires complete Pectoralis major tenotomy. (These patients need to be held in internal rotation with a standard polysling to allow healing of the Pectoralis major tendon)

Locked plates confer angular stability across fusion sites, and as such are more rigid than either screws or intramedullary nails. This gives the advantage of reducing motion to enhance union rates and potentially allowing early weight bearing. The Philos plate (Synthes) is a contoured locking plate designed to fix humeral fractures but which also fits the shape of the hindfoot and provides strong low profile fixation. Its successful use for tibiotalocalcaneal (TTC) arthrodesis has been reported. Our aim was to prospectively evaluate the use of the Philos plate in hindfoot arthrodesis Twenty-one hindfoot arthrodeses were performed using the Philos plate between Oct 2008 and Jan 2010. Patients were followed up for a minimum of 1 year and had preoperative and 6 monthly AOFAS hindfoot scores and serial radiographs until union. Overall there were 15 ankle fusions, 5 tibiotalocalcaneal fusions and 1 subtalar fusion. At 6 months there were 13 unions and 9 non-unions (4 ankle, 5 TTC) giving a non-union rate of 38% overall and 25% for ankle fusions in isolation. Mean AOFAS scores at 6 months were 74/100 for the union group and 47 for non-unions (chi squared p < 0.001). No patient in the non-union group went on to fuse within a year without further surgery. Both groups had similar case mixes including osteoarthritis, AVN of the talus and failed arthroplasty. They also had similar co-morbidities, rates of smokers and bone grafting. Our conclusion is that the high non-union rates are probably due to the lack of compression conferred across the join by the Philos plate as there is no compression hole and we did not supplement the fixation with a lag screw. We recommend using locked plates for hindfoot arthrodesis only with additional compression