Background. The complex deformities in cavovarus feet may be difficult to assess and understand. Weight-bearing CT (WBCT) is increasingly used to evaluate complex deformities. However, the bone axes may be difficult to calculate in the setting of severe deformity. Computer-assisted 3D-axis calculation is a novel approach that may allow for more accurate assessment of foot alignment / deformity. The aim of this study was to assess differences in measurements done manually on 2D slices of WBCT versus 3D computer models in normal and cavus feet. Methods. We retrospectively analyzed WBCT scans from 16 normal and 16 cavus feet in patients with Charcot-Marie Tooth. Eight measurements were assessed: Talus-1. st. metatarsal angle (axial plane), Forefoot arch angle (coronal plane), and Meary's angle, calcaneal pitch, cuneiform to floor, cuneiform to skin, navicular to floor and navicular to skin distance (sagittal plane). 2D measurements were performed manually and 3D measurements were performed using specialised software (BoneLogic, DISIOR). Results. There was no significant difference in the measured variables (2D manual versus 3D automated) in normal feet. In the cavus group, 3D assessment calculated increased values for the sagittal angles: Meary's 7.3 degrees greater (p = 0.004), calcaneal pitch 2.4 degrees greater (p = 0.011)), and lower values for the axial talus-1. st. MT angle, 10.6 degrees less (p = 0.001). Conclusion. There were no significant differences in the normal group. This suggests 3D automated techniques can reliably assess the alignment of bony axes. However, the 3D axis calculations suggest there may be greater sagittal and lesser axial deformity in cavus feet than measured by 2D techniques. This discrepancy may be on account of the rotation seen in cavovarus feet, which may not be readily assessed manually. 3D automated measurements may therefore have a role in better assessing and classifying the cavus foot which may ultimately help inform treatment algorithms

Aims. Cone beam CT allows cross-sectional imaging of the tibiofibular syndesmosis while the patient bears weight. This may facilitate more accurate and reliable investigation of injuries to, and reconstruction of, the syndesmosis but normal ranges of measurements are required first. The purpose of this study was to establish: 1) the normal reference measurements of the syndesmosis; 2) if side-to-side variations exist in syndesmotic anatomy; 3) if age affects syndesmotic anatomy; and 4) if the syndesmotic anatomy differs between male and female patients in weight-bearing cone beam CT views. Patients and Methods. A retrospective analysis was undertaken of 50 male and 50 female patients (200 feet) aged 18 years or more, who underwent bilateral, simultaneous imaging of their lower legs while standing in an upright, weight-bearing position in a pedCAT machine between June 2013 and July 2017. At the time of imaging, the mean age of male patients was 47.1 years (18 to 72) and the mean age of female patients was 57.8 years (18 to 83). We employed a previously described technique to obtain six lengths and one angle, as well as calculating three further measurements, to provide information on the relationship between the fibula and tibia with respect to translation and rotation. Results. The upper limit of lateral translation in un-injured patients was 5.27 mm, so values higher than this may be indicative of syndesmotic injury. Anteroposterior translation lay within the ranges 0.31 mm to 2.59 mm, and -1.48 mm to 3.44 mm, respectively. There was no difference between right and left legs. Increasing age was associated with a reduction in lateral translation. The fibulae of men were significantly more laterally translated but data were inconsistent for rotation and anteroposterior translation. Conclusion. We have established normal ranges for measurements in cross-sectional syndesmotic anatomy during weight-bearing and also established that no differences exist between right and left legs in patients without syndesmotic injury. Age and gender do, however, affect the anatomy of the syndesmosis, which should be taken into account at time of assessment. Cite this article: Bone Joint J 2019;101-B:348–352

Introduction:. Recent published studies have examined the normal dimensions of the syndesmosis on CT. However, previous anatomical studies have shown variations of the articulating facets within the tibialae fibularis and may contribute to the false appearance of increased spacing within the syndesmosis. In this study, we measured and compared anterior and posterior distances of the distal tibiofibular(DTF) syndesmosis on MRI and CT imaging. Methods:. We identified adult patients who had had both a CT scan and an MRI scan of their ipsilateral ankle to investigate symptoms unrelated to the DTF syndesmosis. The anterior and the posterior DTF dimensions were measured on CT and MRI axial images, at the level of the distal tibial physeal scar. This was taken from anterior tubercle of tibia and from the most anterior aspect of the posterior tibial tubercle to the nearest point of medial aspect of the fibula. The geometrical shapes of the syndesmosis and the anterior tibial tubercle were also recorded. Results:. 16 ankles in 15 patients were included. The mean age was 34.6+/−8.8 years. The mean (SD) for the anterior DTF distance was 2.0 mm (0.7 mm) on MRI and 2.9 mm (0.9 mm) on CT whilst the mean posterior DTF distance was 3.2 mm (1.1 mm) on MRI and 4.3 mm (1.0 mm) on CT. This difference reached statistical significance (p < 0.001, paired T-test). When examining the shape of the syndesmosis on MRI, 56% were crescent and 44% rectangular, this was compared to 69% and 31%, respectively, on CT. There was, however, no statistical difference in the shape of the syndesmosis between the two radiological modalities (p=0.625, McNemar test). Conclusion:. CT appears to over-estimate the distal tibiofibular separation and may lead to a false positive diagnosis. Further studies are needed to establish the reliability in the use of CT scans to investigate normal and abnormal syndesmosis

Background

Weightbearing computed tomography scans allow for better understanding of foot alignment in patients with Progressive Collapsing Foot Deformity. However, soft tissue integrity cannot be assessed via WBCT. As performing both WBCT and magnetic resonance imaging is not cost effective, we aimed to assess whether there is an association between specific WBCT and MRI findings.

Introduction:. Fibular malreduction is a common and important cause of pain after surgical fixation following a syndesmosis injury, but it is unclear which components of malreduction correspond to clinical outcome. Plain radiographs have been shown to be unreliable at measuring malreduction when compared to CT scans. A number of published methods for measuring fibular position rely on finding the axis of the fibula. Elgafy demonstrated that fibular morphology varies greatly, and some studies have demonstrated difficulty finding the fibular axis. Methods:. We developed a new method of measuring the distal fibular position on CT images. We used CT studies in 16 normal subjects. Two assessors independently measured the ankle syndesmosis using the Davidovitch method, and our new protocol for fibular AP position, diastasis and fibular length. Results:. We demonstrated that after statistical analysis (Pearson Product Moment Correlation) our method showed improved inter-observer reliability (r = 0.99 and 0.95 vs 0.59 and 0.78 respectively) for diastasis and AP translation, and improved intra-observer reliability (r = 0.99 and 0.99 vs 0.91 and 0.97 respectively). We found inter and intra observer reliability of 0.80 and 0.91 respectively for fibular length, but were unable to find a novel, accurate method for measuring fibular rotation. Conclusions:. Our method is a new, simple, accurate and reproducible system for measuring the ankle syndesmosis. We believe that this method could be used to assess fibular reduction after obtaining CT images of the uninjured side for comparison

Introduction:. Charcot arthropathy is a complex condition affecting diabetic patients with neuropathy. Diagnosis of acute Charcot arthropathy particularly in absence of any perceptible trauma is very challenging as clinically it can mimic osteomyelitis and cellulitis. Delay in recognition of Charcot arthropathy can result in gross instability of foot and ankle. Early diagnosis can provide an opportunity to halt the progression of disease. We report the role of SPECT /CT in the early diagnosis and elucidation of the natural progression of the disease. Methods:. Our multidisciplinary team analysed the scans of neuropathic patients presented with acute red, hot, swollen foot with normal radiological findings (Eichenholtz stage 0), attending the diabetic foot clinic from 2009–2013. The patients were selected from our database, clinic and nuclear medicine records. Initial workup included the assessment of peripheral neuropathy, temperature difference, between the feet, serum inflammatory markers and weight bearing dorsoplantar, lateral and oblique x-rays. All patients had three dimensional triple Phase Bone Scan using 800Mbq . 99m. Tc HDP followed by CT scan. Those patients with obvious radiological findings and signs of infection were excluded. Results:. We evaluated 193 scans in 189 patients. One hundred and forty nine patients showed increase in focal radionuclide uptake at ligament insertion or subchondral bone with a positive predictive value of 77 percent. Forty four out of 193 were negative for Charcot changes and they were not treated as Charcot. These patients did not develop any Charcot changes in the mean follow up of 8 months, indicating a clinically false positive rate of 23%. Conclusion:. SPECT/CT scan is a highly sensitive and specific tool for early diagnosis and accurate localisation of Charcot neuroarthropathy as clinical examination results in high false positive rate. SPECT/CT also helps to understand the natural progression of this disease

Introduction

Pes cavovarus is a foot deformity that can be idiopathic (I-PC) or acquired secondary to other pathology. Charcot-Marie-Tooth disease (CMT) is the most common adult cause for acquired pes cavovarus deformity (CMT-PC). The foot morphology of these distinct patient groups has not been previously investigated. The aim of this study was to assess if morphological differences exist between CMT-PC, I-PC and normal feet (controls) using weightbearing computed tomography (WBCT).

Aim. Single-photon emission computed tomography is a new imaging modality combining high detail CT with highly sensitive triple phase nuclear bone scanning to help clinicians in diagnosis and management of various conditions. Little has been published about its particular usefulness in foot and ankle pathology. We conducted a prospective study to evaluate the role of SPECT for the same. Material and Methods. Fifty patients were seen in a tertiary referral foot and ankle clinic presenting with a variety of foot and ankle conditions. SPECT-CT was requested when a definitive clinical diagnosis could not be reached after thorough clinical examination and plain radiography. Pathology shown by SPECT-CT was taken as the final diagnosis and interventional surgical management carried out accordingly. Patients were subsequently seen in the follow up clinic to evaluate the outcome of their treatment. Results. In eleven (22%) cases, clinical correlation matched with the findings of the SPECT-CT and no change in treatment was necessary. However, in 39 patients (78%) findings of SPECT-CT did not correlate exactly with clinical findings and led to a modified treatment plan. Of these 39 patients, 35 (88%) improved after the intervention based on SPECT-CT findings. Conclusions. We found SPECT-CT to be a very useful investigation in complex foot and ankle cases where definite diagnosis after clinical and simple radiographic examination was still somewhat unclear. Our study suggests that SPECT-CT helps clinical decision making and improves outcome

Aims. The purpose of this study was to assess the success rate and functional outcomes of bone grafting for periprosthetic bone cysts following total ankle arthroplasty (TAA). Additionally, we evaluated the rate of graft incorporation and identified associated predisposing factors using CT scan. Methods. We reviewed a total of 37 ankles (34 patients) that had undergone bone grafting for periprosthetic bone cysts. A CT scan was performed one year after bone grafting to check the status of graft incorporation. For accurate analysis of cyst volumes and their postoperative changes, 3D-reconstructed CT scan processed with 3D software was used. For functional outcomes, variables such as the Ankle Osteoarthritis Scale score and the visual analogue scale for pain were measured. Results. Out of 37 ankles, graft incorporation was successful in 30 cases. Among the remaining seven cases, four (10.8%) exhibited cyst re-progression, so secondary bone grafting was needed. After secondary bone grafting, no further progression has been noted, resulting in an overall 91.9% success rate (34 of 37) at a mean follow-up period of 47.5 months (24 to 120). The remaining three cases (8.1%) showed implant loosening, so tibiotalocalcaneal arthrodesis was performed. Functional outcomes were also improved after bone grafting in all variables at the latest follow-up (p < 0.05). The mean incorporation rate of the grafts according to the location of the cysts was 84.8% (55.2% to 96.1%) at the medial malleolus, 65.1% (27.6% to 97.1%) at the tibia, and 81.2% (42.8% to 98.7%) at the talus. Smoking was identified as a significant predisposing factor adversely affecting graft incorporation (p = 0.001). Conclusion. Bone grafting for periprosthetic bone cysts following primary TAA is a reliable procedure with a satisfactory success rate and functional outcomes. Regular follow-up, including CT scan, is important for the detection of cyst re-progression to prevent implant loosening after bone grafting. Cite this article: Bone Joint J 2024;106-B(5):475–481

Background. Lisfranc fracture dislocations are uncommon injuries, which frequently require surgical intervention. Currently, there is varying evidence on the diagnostic utility of plain radiographs (XR) and CT in identifying Lisfranc injuries and concomitant fractures. Our aim was to identify the utility of XR as compared to CT, with the nul hypothesis that there was no difference in fracture identification. Methods. A retrospective assessment of patients who had sustained a Lisfranc injury between 2013 and 2022 across two trauma centres within the United Kingdom who underwent surgery. Pre-operative XR and CT images were reviewed independently by 2 reviewers to identify the presence of associated fractures. Results. A total of 175 patients were included. Our assessment identified that XR images significantly under-diagnosed all metatarsal and midfoot fractures. The largest discrepancies between XR and CT in their rates of detection were in fractures of the cuboid (5.7% vs 28%, p<0.001), medial cuneiform (20% vs 51%, p=0.008), lateral cuneiform (4% vs 36%, p=0.113), second metatarsal (57% vs 82%, p<0.001), third metatarsal (37% vs 61%, p<0.001) and fourth metatarsal (26% vs 43%, p<0.001). As compared to CT, the sensitivity of XR was low. The lowest sensitivity for identification however was lateral foot injuries, specifically fractures of the lateral cuneiform (sensitivity 7.94%, specificity 97.3%), cuboid (sensitivity 18.37%, specificity 99.21%), fourth (sensitivity 46.7%, specificity 89.80%) and fifth metatarsal (sensitivity 45.00%, specificity 96.10%). Conclusion. From our analysis, we can determine that XR significantly under-diagnoses associated injuries in patient sustaining an unstable Lisfranc injury, with lateral foot injuries being the worst identified. We advised the use of CT imaging in all cases for appropriate surgical planning

Introduction. The current treatment for Freiberg's osteochondrosis centres around either: simple debridement or debridement osteotomy. The main principle of the osteotomy is to rotate normal articular cartilage into the affected area. We recommend the use of CT scanning to delineate the amount of available, unaffected cartilage available to rotate into the affected space. Methods. We retrospectively reviewed 32 CT scans of new Freiberg's diagnoses in Sheffield over a 10 year period using the PACS system. We identified the sagittal CT slice that displayed the widest portion of proximal articular margin of the proximal phalanx and measured the diseased segment of the corresponding metatarsal head as an arc (in degrees). This arc segment was divided by 360°. This gave a ratio of the affected arc in the sagittal plane. Results. 28 out of 32 cases involved the 2nd metatarsal with the remaining 4 involving the 3rd metatarsal head. Of 32 cases, 18 had fragmentation. Surgically, 20 had debridement only, 5 also had an osteotomy and 1 had a fusion. 6 of the 32 cases were managed non-operatively. 11 cases out of 32 had an arc ratio of < 0.3. Of these, only 3 had an osteotomy, 3 had no procedure and 5 had a simple debridement. Of those that had osteotomies (5/32), 3 of the 5 cases had an arc ratio of < 0.3 with the other 2 being 0.42 and 0.38. Discussion. We hypothesise that those cases with an arc ratio of less 0.3 would be amenable to a dorsal closing wedge osteotomy and those with a ratio of more than 0.4 would be better suited to a simple debridement. For those cases between 0.3–0.4, we feel either option is viable. Further work to prove or disprove outcomes related to our classification is required

Background. The importance of total ankle replacement (TAR) implant orientation in the axial plane is poorly understood with major variation in surgical technique of implants on the market. Our aims were to better understand the axial rotational profile of patients undergoing TAR. Methods. In 157 standardised CT Scans of end-stage ankle arthritis patients planning to undergo primary TAR surgery, we measured the relationship between the knee posterior condylar axis, the tibial tuberosity, the transmalleolar axis(TMA) and the tibiotalar angle. The foot position was measured in relation to the TMA with the foot plantigrade. The variation between medial gutter line and the line bisecting both gutters was assessed. Results. The mean external tibial torsion was 34.5±10.3°(11.8–62°). When plantigrade the mean foot position relative to the TMA was 21±10.6°(0.7–38.4°) internally rotated. As external tibial torsion increased, the foot position became more internally rotated relative to the TMA(pearson correlation 0.6;p< 0.0001). As the tibiotalar angle became more valgus, the foot became more externally rotated relative to the TMA(pearson correlation −0.4;p< 0.01). The mean difference between the medial gutter line and a line bisecting both gutters was 4.9±2.8°(1.7°-9.4°). More than 51% of patients had a difference greater than 5°. The mean angle between the medial gutter line and a line perpendicular to the TMA was 7.5°±2.6°(2.8°-13.7°). Conclusion. There is a large variation in rotational profile of patients undergoing TAR, particularly between the medial gutter line and the transmalleolar axis. Surgeon designers and implant manufacturers need to develop consistent methods to guide surgeons towards judging appropriate axial rotation of their implanton an individual basis. We recommend careful clinical assessment and CT scanspre-operatively to enable the correct rotation to be determined

Aims. The first metatarsal pronation deformity of hallux valgus feet is widely recognized. However, its assessment relies mostly on 3D standing CT scans. Two radiological signs, the first metatarsal round head (RH) and inferior tuberosity position (ITP), have been described, but are seldom used to aid in diagnosis. This study was undertaken to determine the reliability and validity of these two signs for a more convenient and affordable preoperative assessment and postoperative comparison. Methods. A total of 200 feet were randomly selected from the radiograph archives of a foot and ankle clinic. An anteroposterior view of both feet was taken while standing on the same x-ray platform. The intermetatarsal angle (IMA), metatarsophalangeal angle (MPA), medial sesamoid position, RH, and ITP signs were assessed for statistical analysis. Results. There were 127 feet with an IMA > 9°. Both RH and ITP severities correlated significantly with IMA severity. RH and ITP were also significantly associated with each other, and the pronation deformities of these feet are probably related to extrinsic factors. There were also feet with discrepancies between their RH and ITP severities, possibly due to intrinsic torsion of the first metatarsal. Conclusion. Both RH and ITP are reliable first metatarsal pronation signs correlating to the metatarsus primus varus deformity of hallux valgus feet. They should be used more for preoperative and postoperative assessment. Cite this article: Bone Jt Open 2024;5(11):1037–1040

Objective. The purpose of this study was to determine the outcomes of revision ankle replacements, using the Invision implant and impaction allograft for massive talar dome defects following primary ankle replacement failure. Outcomes were assessed in terms of bone graft incorporation; improvement in patient reported outcome measures (PROMs); and survivorship of the revision ankle arthroplasty. Methods. A retrospective review of prospectively collected data identified eleven patients who had massive bone cysts and underwent revision of a failed primary total ankle replacement to the Invision revision system, combined with impaction grafting using morselized femoral head allograft. These revisions occurred at a single high volume ankle arthroplasty centre. Computed tomography (CT) scans were used to assess bone graft incorporation and the Manchester-Oxford Foot Questionnaire (MOXFQ) and EQ-5D scores were used pre and post operatively to assess PROMs. Results. The mean follow up was 18 months (12–48months). In all eleven patients, improvement was reported in the post-operative MOXFQ and EQ-5D scores. CT scans showed bone graft incorporation in all cases. None of the patients have required further surgery and are continue to do well clinically at latest follow up. Conclusions. In the short term, this study confirms revision ankle replacements with the Invision prosthesis and impaction with morselized femoral head allograft is a suitable revision option for primary ankle replacement failure with massive talar bone loss. Long term follow up continues of these complex patients

Introduction. The treatment of posterior malleolar fractures is developing. Mason and Molloy (Foot Ankle Int. 2017 Nov;38(11):1229-1235) identified only 49% of posterior malleolar rotational pilon type fractures had syndesmotic instabilities. This was against general thinking that fixation of such a fragment would stabilize the syndesmosis. Methods. We examined 10 cadaveric lower limbs that had been preserved for dissection at the Human Anatomy and Resource Centre at Liverpool University in a solution of formaldehyde. The lower limbs were carefully dissected to identify the ligamentous structures on the posterior aspect of the ankle. To compare the size to the rotational pilon posterior malleolar fracture (Mason and Molloy 2A and B) we gathered information from our posterior malleolar fracture database. 3D CT imaging was analysed using our department PACS system. Results. The PITFL insertion on the posterior aspect of the tibia is very large. The average size of insertion was 54.9×47.1mm across the posterior aspect of the tibia. Medially the PITFL blends into the sheath of tibialis posterior and laterally into the peroneal tendon sheath. 78 posterior lateral and 35 posterior medial fragments were measured. On average, the lateral to medial size of the posteromalleolar fragment was 24.5mm in the posterolateral fragment, and 43mm if there is a posteromedial fragment present also. The average distal to proximal size of the posterolateral fragment was 24.5mm and 18.5mm for the posteromedial fragment. Conclusion. The PITFL insertion on the tibia is broad. In comparison to the average size of the posterior malleolar fragments, the PITFL insertion is significantly bigger. Therefore, for a posterior malleolar fracture to cause posterior syndesmotic instability, a ligamentous injury will also have to occur. This explains the finding by Mason and Molloy that only 49% of type 2 injuries had a syndesmotic injury on testing

Background. Undisplaced Lisfranc-type injuries are subtle but potentially unstable fracture-dislocations with little known about the natural history. These injuries are often initially managed conservatively due to lack of initial displacement and uncertainty regarding subsequent instability at the tarsometatarsal joints (TMTJ). The aim of this study was to determine the secondary displacement rate and the need for delayed operative intervention in undisplaced Lisfranc injuries that were managed conservatively at initial presentation. Methods. Over a 6-year period (2011 to 2017), we identified 24 consecutive patients presenting to a university teaching hospital with a diagnosis of an undisplaced Lisfranc-type injury that was initially managed conservatively. Pre-operative radiographs were reviewed to confirm the undisplaced nature of the injury (defined as a diastasis< 2mm at the second TMTJ). The presence of a ‘fleck’ sign (small bony avulsion of the second metatarsal) was also noted. Electronic patient records and sequential imaging (plain radiographs/CT/MRI) were scrutinized for demographics, mechanism of injury and eventual outcome. Results. The mean age of the patients at the time of injury was 42 years (19 Female). 96% (23/24) were low energy injuries and 88% (21/24) had a positive ‘fleck sign’. The secondary displacement rate in this group of patients was 62.5% (15/24) over a median interval of 14 days (range 0 to 482 days). 12 patients underwent open reduction internal fixation after a median interval of 29 days (range 1 to 294 days) from their initial injury. One patient required TMTJ fusion at 19 months and two patients were managed non-operatively. The injury remained undisplaced in 37.5% patients (9/24) with only one patient requiring subsequent TMTJ fusion at 5 months. Conclusion. Undisplaced Lisfranc injuries have a high rate of secondary displacement and warrant close follow-up. Early primary stabilisation of undisplaced Lisfranc injuries should be considered to prevent unnecessary delays in surgical treatment

Background. The cavovarus foot is a complex 3-dimensional deformity. Although a multitude of techniques are described for its surgical management, few of these are evidence based or guided by classification systems. Surgical management involves realignment of the hindfoot and soft tissue balancing, followed by forefoot balancing. Our aim was to classify the pattern of residual forefoot deformities once the hindfoot is corrected, to guide forefoot correction. Methods. We included 20 cavovarus feet from adult patients with Charcot-Marie-Tooth who underwent weightbearing CT (mean age 43.4 years, 14 males). Patients included had flexible deformities, with no previous surgery. Previous work established majority of rotational deformity in cavovarus feet occurs at the talonavicular joint, which is often reduced during surgery. Using specialised software (Bonelogic 2.1, Disior) a 3-dimensional, virtual model was created. Using data from normal feet as a guide, the talonavicular joint of the cavovarus feet was digitally reduced to a ‘normal’ position. Models of the corrected position were exported and geometrically analysed using Blender 3.6 to identify anatomical trends. Results. We identified 3 types of cavovarus forefoot morphotypes. Type 1 was seen in 13 cases (65%) and was defined as a foot where only the first metatarsal was relatively plantarflexed to the rest of the foot, with no significant residual adduction after talonavicular correction. Type 2 was seen in 4 cases (20%) and was defined as a foot where the second and first metatarsals were progressively plantarflexed, with no significant adduction. Type 3 was seen in 3 cases (15%) and was defined as a foot where the metatarsals were still adducted after talonavicular de-rotation. Conclusion. We classify 3 forefoot morphotypes in cavovarus feet. It is important to recognise and anticipate the residual forefoot deformities after hindfoot correction as different treatment strategies may be required for different morphotypes to achieve balanced correction

Background. Ankle and hindfoot fusion in the presence of large bony defects represents a challenging problem. Treatment options include acute shortening and fusion or void filling with metal cages or structural allograft, which both have historically low union rates. Impaction grafting is an alternative option. Methods. A 2 centre retrospective review of consecutive series of 32 patients undergoing hindfoot fusions with impaction bone grafting of morselised femoral head allograft to fill large bony void defects was performed. Union was assessed clinically and with either plain radiography or weightbearing CT scanning. Indications included failed total ankle replacement (24 patients), talar osteonecrosis (6 patients) and fracture non-union (2 patients). Mean depth of the defect was 29 ±10.7 mm and mean maximal cross-sectional area was 15.9 ±5.8 cm. 2. Tibiotalocalcaneal (TTC) arthrodesis was performed in 24 patients, ankle arthrodesis in 7 patients and triple arthrodesis in 1 patient. Results. Mean age was 57 years (19–76 years). Mean follow-up of 22.8 ±8.3 months. 22% were smokers. There were 4 tibiotalar non-unions (12.5%), two of which were symptomatic. 10 TTC arthrodesis patients united at the tibiotalar joint but not at the subtalar joint (31.3%), but only two of these were symptomatic. The combined symptomatic non-union rate was 12.5%. Mean time to union was 9.6 ±5.9 months. One subtalar non-union patient underwent re-operation at 78 months post-operatively after failure of metalwork. Two (13%) patients developed a stress fracture above the metalwork that healed with non-operative measures. There was no bone graft collapse with all patients maintaining bone length. Conclusion. Impaction of morselised femoral head allograft can be used to fill large bony voids around the ankle and hindfoot when undertaking arthrodesis, with rapid graft incorporation and no graft collapse despite early loading. This technique offers satisfactory union outcomes without the need for shortening or synthetic cages

Introduction. AlloStem/Cellular Bone Allograft and autologous bone graft are accepted methods for managing hindfoot degenerative arthritis. The purpose was to evaluate outcomes of AlloStem and autograft in subtalar arthrodesis and compare overall fusion rates. Methods. This study was conducted in IRB compliance. Patients between 18–80 years who qualified for a subtalar fusion were randomized 1:1 to AlloStem or autologous graft. The AOFAS hindfoot ankle scale, FFI-R and SF-12 were collected pre-operatively, 6 weeks, 3 & 6 months, 1 and 2 year. Weight-bearing 3-view ankle X-rays were done at the same intervals. A CT scan was obtained at 6 months. Results. 140 patients were enrolled; 124 patients had surgery(60-AlloStem and 64-Control). Withdrawals included 14 voluntarily before surgery and 2 intra-operative failures. 19 were lost to follow-up. Mean age for AlloStem was 56.69(20.3–79.6) and Autograft was 54.60(20.74–80.07). 59 AlloStem patients completed their 6 month visit and 45 completed 2 years. AOFAS score improved: 40.02 at pre-op to 72.16(6 mo) to 79.51 at 1 year and 80.38 at 2 year. SF-12 improved 58.29 at pre-op to 65.67 at 6 month and 71.59 at 2 year. FFI-R improved 236.88 at pre-op to 203.53 at 6 month 149.93 at 2 year.60 Autograft patients completed their 6 month visit and 51 patients completed their 2 year. AOFAS score improved 42.89 at pre-op to 75.67 (6 mo) to 79.75 at 1 year and 78.62 at 2 year. Autograft SF-12 improved 60.55 at pre-op to 70.40 at 6 month and 75.26 at 2 year. Autograft FFI-R improved 217.16 at pre-op to 166.77 at 6 month and 145.43 at 2 year. AlloStem patients had a mean posterior fusion rate of 28.9% at 6 months whereas the Autograft had 46.3%(p=.049). Non-union rates were AlloStem(9/57)(15.7%) whereas Autograft was 3/60(5%). Conclusion. AlloStem trended to be inferior to Autologous graft

Introduction. Primary ankle arthroplasty (TAR) is increasingly used to treat end-stage ankle arthritis. Reported revision rates of TAR vary from 8.5% to 11.1% at 9 years. Revision surgery remains technically challenging with options ranging from simple joint debridement to tibio-talar-calcaneal fusion. The efficacy of these procedures remains unclear and there is no consensus on optimal revision options. Methods. A retrospective cohort study was performed of all patients undergoing surgery for a failed primary TAR at the Nuffield Orthopaedic Centre (2004–2021). TAR failure was determined by clinical assessment, serial radiographs and CT scans. Primary outcome measures included type and time of index surgery post TAR. Secondary outcomes included frequency of re-operations, post-operative complications, patient reported outcomes and union rate (for revision arthrodesis procedures). Results. 70 failed TARs in 69 patients (35M:34F, mean 65.7 years, s.d.=11.6) underwent re-operation a mean of 6.24 years (range 1–30) post primary. In total, 107 operations were performed including revision fusion (n=50), revision arthroplasty (n=14), bearing exchange (n=9) and joint clearance (n=9). The overall revision fusion union rate was 73.5% over a mean of 12.5 months (s.d.=7.6). 16/23 (69.6%) Tibio-Talo-Calcaneal and 9/12 (75%) ankle fusions (previous subtalar/triple fusion) using a hindfoot nail united over a mean 11.4 months (s.d.=6.0) and 15 months (s.d.=9.48) respectively. Only 64% of ankle fusions using screws alone united (mean=10.6 months, s.d.=8.14). The average post-operative MOXFQ score was 28.3 (s.d.=19.3). 73% said the operation improved their function and would recommend it to a friend/family member. Conclusion. Despite low post-operative MOXFQ scores, over 70% of patients were satisfied with re-operation for a failed TAR. Over 26% of all TAR revision fusions fail to unite with the highest non-union rates observed post ankle arthrodesis with screws alone (36.4%)