Aims. Arthroplasty has become increasingly popular to treat end-stage ankle arthritis. Iatrogenic posterior neurovascular and tendinous injury have been described from saw cuts. However, it is hypothesized that posterior ankle structures could be damaged by inserting tibial guide pins too deeply and be a potential cause of residual hindfoot pain. Methods. The preparation steps for ankle arthroplasty were performed using the Infinity total ankle system in five right-sided cadaveric ankles. All tibial guide pins were intentionally inserted past the posterior tibial cortex for assessment. All posterior ankles were subsequently dissected, with the primary endpoint being the presence of direct contact between the structure and pin. Results. All pin locations confer a risk of damaging posterior ankle structures, with all posterior ankle structures except the flexor hallucis longus tendon being contacted by at least one pin. Centrally-aligned transcortical pins were more likely to contact posteromedial neurovascular structures. Conclusion. These findings support our hypothesis that tibial guide pins pose a considerable risk of contacting and potentially damaging posterior ankle structures during ankle arthroplasty. This study is the first of its kind to assess this risk in the Infinity total ankle system. Cite this article: Bone Jt Open 2021;2(7):503–508

Lisfranc injuries were previously described as fracture-dislocations of the tarsometatarsal joints. With advancements in modern imaging, subtle Lisfranc injuries are now more frequently recognized, revealing that their true incidence is much higher than previously thought. Injury patterns can vary widely in severity and anatomy. Early diagnosis and treatment are essential to achieve good outcomes. The original classification systems were anatomy-based, and limited as tools for guiding treatment. The current review, using the best available evidence, instead introduces a stability-based classification system, with weightbearing radiographs and CT serving as key diagnostic tools. Stable injuries generally have good outcomes with nonoperative management, most reliably treated with immobilization and non-weightbearing for six weeks. Displaced or comminuted injuries require surgical intervention, with open reduction and internal fixation (ORIF) being the most common approach, with a consensus towards bridge plating. While ORIF generally achieves satisfactory results, its effectiveness can vary, particularly in high-energy injuries. Primary arthrodesis remains niche for the treatment of acute injuries, but may offer benefits such as lower rates of post-traumatic arthritis and hardware removal. Novel fixation techniques, including suture button fixation, aim to provide flexible stabilization, which theoretically could improve midfoot biomechanics and reduce complications. Early findings suggest promising functional outcomes, but further studies are required to validate this method compared with established techniques. Future research should focus on refining stability-based classification systems, validation of weightbearing CT, improving rehabilitation protocols, and optimizing surgical techniques for various injury patterns to ultimately enhance patient outcomes. Cite this article: Bone Joint J 2024;106-B(12):1431–1442

Background. Research on midfoot injuries have primarily concentrated on the central column and the Lisfranc ligament without amassing evidence on lateral column injuries. Lateral column injuries have historically been treated with Kirschner wire fixation when encountered. Objective. Our aim in this study was to analyse lateral column injuries to the midfoot, their method of treatment and the radiological lateral column outcomes. Our nul hypothesis being that fixation is required to obtain and maintain lateral column alignment. Methods. Data was retrospectively collected from four centres on surgically treated midfoot fracture dislocations between 2011 and 2021. Radiographs were analysed using departmental PACS. All statistics was performed using SPSS 26. Results. A total of 235 cases were diagnosed as having a lateral column injury out of the 409 cases included. On cross tabulation, there was a significant association with having a central column injury (234/235, p<.001) and 70% of cases (166/235) also had an additional medial column injury. Of the 235 lateral column injuries, data was available regarding fixation radiographic alignment on 222 cases. There were 44 cases which underwent Kirschner wire fixation, 23 plate fixations and 3 screw fixations. Lateral column alignment loss was seen in 2.84% (4/141) of those which didn't undergo fixation, 13.64% (6/44) which underwent K wires, and 0 % in those fixed by screws or K wires. Conclusion. Lateral column injury occurs in over half of midfoot fractures in this study. It rarely occurs alone and is most commonly related to three column injuries. Nevertheless, following stabilisation of the central column, additional fixation of injuries to the lateral column do not appear beneficial. The use of a bridge plate to fix the central column appears protective and purely ligamentous injury was a higher risk than an injury that included the bone

Background. The use of a knotless TightRope for the stabilisation of a syndesmotic injury is a well-recognised mode of fixation. It has been described that the device can be inserted using a “closed” technique. This presents a risk of saphenous nerve entrapment and post-operative pain. Aim. We aimed to establish the actual risk of injury to the Saphenous Nerve using a “closed” technique for the insertion of a TightRope. Method. 20 TightRopes were inserted into Fresh Frozen Cadavers. This was done using the senior authors preferred technique of divergent tightropes with the distal implant directed slightly anterior to the fibula-tibia axis and the proximal implant slightly posterior in order to simulate the greatest risk to the nerve. This was done under image Intensifier guidance to simulate an intraoperative environment. The medial side of the distal tibia was then dissected to directly record and measure the relationship of the TightRope to the Saphenous Nerve. Measurements were taken using digital calipers from the centre of the button on the medial side of the TightRope to the centre of the nerve at the point of closest proximity. Results. 12 TightRopes were found to exit posterior to the nerve, 7 anterior and 1 penetrated through the centre of the nerve. The mean distance from the centre of the button to the nerve was 6.99mm (range 0.72–14.52mm, standard deviation 4.33mm). In 9 of the 20 TightRopes, the nerve was found to be less than 5mm away. Conclusion. Our findings demonstrated that the risks of damaging or indeed entrapping the Saphenous nerve were high, and therefore we would advocate an open incision on the medial side with judicious exploration to ensure there is no damage to the medial neurological structures

Sporting injuries around the ankle vary from simple sprains that will resolve spontaneously within a few days to severe injuries which may never fully recover and may threaten the career of a professional athlete. Some of these injuries can be easily overlooked altogether or misdiagnosed with potentially devastating effects on future performance. In this review article, we cover some of the common and important sporting injuries involving the ankle including updates on their management and outcomes. Cite this article: Bone Joint J 2016;98-B:874–83

Aims. In a randomized controlled trial with two-year follow-up, patients treated with suture button (SB) for acute syndesmotic injury had better outcomes than patients treated with syndesmotic screw (SS). The aim of this study was to compare clinical and radiological outcomes for these treatment groups after five years. Methods. A total of 97 patients with acute syndesmotic injury were randomized to SS or SB. The five-year follow-up rate was 81 patients (84%). The primary outcome was the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle Hindfoot Scale. Secondary outcome measures included Olerud-Molander Ankle (OMA) score, visual analogue scale (VAS), EuroQol five-dimension questionnaire (EQ-5D), range of movement, complications, reoperations, and radiological results. CT scans of both ankles were obtained after surgery, and after one, two, and five years. Results. The SB group had higher median AOFAS score (100 (interquartile range (IQR) 92 to 100) vs 90 (IQR 85 to 100); p = 0.006) and higher median OMA score (100 (IQR 95 to 100) vs 95 (IQR 75 to 100); p = 0.006). The SS group had a higher incidence of ankle osteoarthritis (OA) (24 (65%) vs 14 (35%), odds ratio (OR) 3.4 (95% confidence interval (CI) 1.3 to 8.8); p = 0.009). On axial CT we measured a significantly smaller mean difference in the anterior tibiofibular distance between injured and non-injured ankles in the SB group (–0.1 mm vs 1.2 mm; p = 0.016). Conclusion. Five years after syndesmotic injury treated with either SB or SS, we found better AOFAS and OMA scores, and lower incidence of ankle OA, in the SB group. These long-term results favour the use of SB when treating an acute syndesmotic injury. Cite this article: Bone Joint J 2020;102-B(2):212–219

Aims. Fractures of the navicular can occur in isolation but, owing to the intimate anatomical and biomechanical relationships, are often associated with other injuries to the neighbouring bones and joints in the foot. As a result, they can lead to long-term morbidity and poor function. Our aim in this study was to identify patterns of injury in a new classification system of traumatic fractures of the navicular, with consideration being given to the commonly associated injuries to the midfoot. Patients and Methods. We undertook a retrospective review of 285 consecutive patients presenting over an eight- year period with a fracture of the navicular. Five common patterns of injury were identified and classified according to the radiological features. Type 1 fractures are dorsal avulsion injuries related to the capsule of the talonavicular joint. Type 2 fractures are isolated avulsion injuries to the tuberosity of the navicular. Type 3 fractures are a variant of tarsometatarsal fracture/dislocations creating instability of the medial ray. Type 4 fractures involve the body of the navicular with no associated injury to the lateral column and type 5 fractures occur in conjunction with disruption of the midtarsal joint with crushing of the medial or lateral, or both, columns of the foot. Results. In order to test the reliability and reproducibility of this new classification, a cohort of 30 patients with a fracture of the navicular were classified by six independent assessors at two separate times, six months apart. Interobserver reliability and intraobserver reproducibility both had substantial agreement, with kappa values of 0.80 and 0.72, respectively. Conclusion. We propose a logical, all-inclusive, and mutually exclusive classification system for fractures of the navicular that gives associated injuries involving the lateral column due consideration. We have shown that this system is reliable and reproducible and have described the rationale for the subsequent treatment of each type. Cite this article: Bone Joint J 2018;100-B:176–82

Aims. This study reports the outcomes of a technique of soft-tissue coverage and Chopart amputation for severe crush injuries of the forefoot. Patients and Methods. Between January 2012 to December 2016, 12 patients (nine male; three female, mean age 38.58 years; 26 to 55) with severe foot crush injury underwent treatment in our institute. All patients were followed-up for at least one year. Their medical records, imaging, visual analogue scale score, walking ability, complications, and functional outcomes one year postoperatively based on the American Orthopedic Foot and Ankle Society (AOFAS) and 36-Item Short-Form Health Survey (SF-36) scores were reviewed. Results. The mean length of follow-up was 18.6 months (13 to 28). Two patients had a local infection, flap necrosis was seen in one patient, and one patient experienced a skin graft wound healing delay. Of the 12 patients, one had persistent infection and eventually required below-knee amputation, but pain-free walking was achieved in all the other patients. The mean one-year postoperative AOFAS and SF-36 scores were 75.6 (68 to 80) and 82 (74 to 88), respectively. Conclusion. Although our sample size was small, we believe that this treatment method may be a valuable alternative for treating severe foot crush injuries. Cite this article: Bone Joint J 2018;100-B:1359–63

Introduction. Injury to the syndesmosis is not always clearly demonstrated on radiographs and different tests have been described to assess for injury. In the presence of a significant injury to the syndesmosis, surgical fixation is often indicated and various fixation methods have been described. If the result of surgery is any mal-reduction of the fibula, this may result in ongoing ankle pain. Assessing how well the fibula has been reduced intra-operatively is currently limited to image intensifier views. We have previously developed a simple assessment, which has been shown to give accurate intra-operative demonstration of an injury to the syndesmosis. Our objective was to ascertain if the same test could demonstrate any malreduction of the fibular after repair of a syndesmosis injury. Methods. Seven fresh frozen cadavers had complete sydesmosis disruption performed before fixation using a well-recognised technique with a single 3.5 mm small fragment screw. Purposeful malreduction was performed in three ankles and standard reduction in the remaining four. 2–5mls of contrast medium was then injected into the ankle joint. Results. When there had been a malreduction, an obvious ‘blush’ of dye leaked superiorly into the surrounding soft tissues, whereas a normal ankle arthrogram was shown when the fibular had been anatomically reduced into the incisura and well fixed. Conclusion. This cadaveric study showed the test to be an easy and reliable adjuct to assess for acute malreduction of a syndesmosis injury

Objectives. The surgical challenge with severe hindfoot injuries is one of technical feasibility, and whether the limb can be salvaged. There is an additional question of whether these injuries should be managed with limb salvage, or whether patients would achieve a greater quality of life with a transtibial amputation. This study aims to measure functional outcomes in military patients sustaining hindfoot fractures, and identify injury features associated with poor function. Methods. Follow-up was attempted in all United Kingdom military casualties sustaining hindfoot fractures. All respondents underwent short-form (SF)-12 scoring; those retaining their limb also completed the American Academy of Orthopaedic Surgeons Foot and Ankle (AAOS F&A) outcomes questionnaire. A multivariate regression analysis identified injury features associated with poor functional recovery. Results. In 12 years of conflict, 114 patients sustained 134 fractures. Follow-up consisted of 90 fractures (90/134, 67%), at a median of five years (interquartile range (IQR) 52 to 80 months). The median Short-Form 12 physical component score (PCS) of 62 individuals retaining their limb was 45 (IQR 36 to 53), significantly lower than the median of 51 (IQR 46 to 54) in patients who underwent delayed amputation after attempted reconstruction (p = 0.0351). Regression analysis identified three variables associated with a poor F&A score: negative Bohler’s angle on initial radiograph; coexisting talus and calcaneus fracture; and tibial plafond fracture in addition to a hindfoot fracture. The presence of two out of three variables was associated with a significantly lower PCS compared with amputees (medians 29, IQR 27 to 43 vs 51, IQR 46 to 54; p < 0.0001). Conclusions. At five years, patients with reconstructed hindfoot fractures have inferior outcomes to those who have delayed amputation. It is possible to identify injuries which will go on to have particularly poor outcomes. Cite this article: P. M. Bennett, T. Stevenson, I. D. Sargeant, A. Mountain, J. G. Penn-Barwell. Outcomes following limb salvage after combat hindfoot injury are inferior to delayed amputation at five years. Bone Joint Res 2018;7:131–138. DOI: 10.1302/2046-3758.72.BJR-2017-0217.R2

Injuries to the foot in athletes are often subtle and can lead to a substantial loss of function if not diagnosed and treated appropriately. For these injuries in general, even after a diagnosis is made, treatment options are controversial and become even more so in high level athletes where limiting the time away from training and competition is a significant consideration. In this review, we cover some of the common and important sporting injuries affecting the foot including updates on their management and outcomes. Cite this article: Bone Joint J 2016;98-B:1299–1311

Isolated dislocations of the navicular are rare injuries; we present our experience of six cases in which the navicular was dislocated without fracture. All patients had complex injuries, with considerable disruption of the midfoot. Five patients had open reduction and stabilisation with Kirschner wires. One developed subluxation and deformity of the midfoot because of inadequate stabilisation of the lateral column, and there was one patient with ischaemic necrosis. We believe that the navicular cannot dislocate in isolation because of the rigid bony supports around it; there has to be significant disruption of both longitudinal columns of the foot. Most commonly, an abduction/pronation injury causes a midtarsal dislocation, and on spontaneous reduction the navicular may dislocate medially. This mechanism is similar to a perilunate dislocation. Stabilisation of both medial and lateral columns of the foot may sometimes be essential for isolated dislocations. In spite of our low incidence of ischaemic necrosis, there is always a likelihood of this complication

Introduction. Lisfranc joint injuries are increasingly recognised in elite soccer and rugby players. Currently no evidence-based guidelines exist on timeframes for return to training and competition following surgical treatment. This study aimed to see whether return to full competition following surgery for Lisfranc injuries was possible in these groups and to assess times to training, playing and possible related factors. Material/Methods. Over 46-months, a consecutive series of fifteen professional soccer (6) and rugby(9) players in the English Premierships/Championship, was assessed using prospectively collected data. All were isolated injuries, sustained during competitive matches. Each had clinical and radiological evidence of injury and was treated surgically within thirty-one days. A standardised postoperative regime was used. Results. Follow-up was obtained in all fifteen cases. Eight cases were ligamentous injuries and seven were bony. Time from injury to fixation ranged from 10–31 days. One athlete retired following a ligamentous injury. All remaining fourteen returned to training and full competition. Excluding the retired case, mean return to training time was 20.2 weeks and to full competition was 25.6 weeks. No significant difference existed between the mean return to competition time for rugby (27.8 weeks) and soccer(24.7 weeks). A significant difference existed between the mean return to competition time for ligamentous (23.7 weeks) compared to bony(27.6 weeks) injuries(p = 0.012). Three patients suffered deep peroneal nerve sensation loss, two of which fully recovered. Discussion/Conclusion. Return to competitive elite-level soccer and rugby is possible following surgically treated Lisfranc injuries. Return to training can take up to 24 weeks and playing up to 31 weeks, with bony injuries taking longer. To our knowledge this is the largest series of its kind and whilst we recognise it contains small numbers, we feel it provides some guidance on rehabilitative timeframes for those who treat and those who sustain these injuries. Evidence Level: 4

We used MRI to study a prospective series of 95 patients with inversion injuries of the ankle and no fracture on plain radiographs. We found an incidence of bone bruises of 27%, but these made no difference to the time of return to work, limitation of walking or physical activity, or the clinical outcome scores at three months. We conclude that bone bruises have very little clinical significance after inversion injuries of the ankle

We report an audit of 208 patients with a mean age of 39 years (16 to 65) attending the Orthopaedic Assessment Unit at the Wellington Hospital between January 2006 and December 2007 with an injury of the tendo Achillis requiring immobilisation in a cast. Information on assessment of venous thromboembolism (VTE) risk, prophylactic measures and VTE events for all patients was obtained from the medical records. A VTE risk factor was documented in the records of three (1%) patients. One of the 208 patients received aspirin prophylaxis; none received low molecular weight heparin. In all, 13 patients (6.3%, 95% confidence interval 3.4 to 10.5) developed symptomatic VTE during immobilisation in a cast, including six with a distal deep-vein thrombosis (DVT), four with a proximal DVT, and three with a confirmed pulmonary embolus. This incidence of symptomatic VTE is similar to that reported following elective hip replacement. We propose that consideration is given to VTE prophylaxis during prolonged immobilisation of the lower limbs in a cast, to ensure that the same level of protection is provided as for patients undergoing elective hip replacement

Introduction:. Isolated Weber B lateral malleolus fractures heal uneventfully, but concern that late subluxation may occur due to unrecognised medial ligament tearing, despite an intact mortice on initial radiographs, often results in overtreatment. The aim of this study was to determine the incidence of late talar shift with nonoperative management in a cohort of patients with no initial talar shift, and also record functional outcomes at 16–28 months following injury. Methods:. This was a retrospective review of 129 patients with Weber B lateral malleolar fractures initially referred to the fracture clinic between October 2011 and October 2012. Eight had obvious talar shift and therefore underwent surgery, with the remaining 121 treated in plaster (n=41), a Velcro boot (n=70) or bandage (n=10). No stress x-rays or MRI scans were performed. Weight-bearing was permitted as pain allowed. Radiographs taken on discharge from the clinic were reviewed to assess talar shift. Functional outcomes assessment was carried out using Manchester Oxford Foot Questionnaire and Olerud-Molander score. Results:. None of the 121 patients had talar shift initially; 21 patients where medial injury was strongly suspected were closely followed and had check x-rays more often (average 2.9 appointments per patient) than the other groups. No patients had talar shift in any of the subsequent x-rays and therefore none underwent delayed internal fixation. The mean MOXFQ and Olerud-Molander scores were 27 and 78 respectively in 57 patients and the functional outcomes were not influenced by type of immobilisation or suspected medial injury. Conclusion:. Our observation is that the risk of late talar shift is likely to be low in patients where initial x-rays had showed no talar displacement. It may be unnecessary to perform additional tests/imaging to establish the integrity of the medial ligament as satisfactory functional results are routinely observed

Introduction. Minimally invasive Achilles tendon repair has recently gained popularity amongst foot and ankle surgeons. This study aims to quantify the risk of sural nerve injury when using the Achillon device (Integra), as well as delineate its anatomical relationship to the Achilles tendon. Methods. In 15 cadaveric specimens, the Achilles tendon was transected through a 2cm transverse incision made 4cm proximal to the palpable Achilles tendon insertion point. The Achillon device was inserted beneath the paratenon both proximally and distally and six needle passers mounted with sutures were introduced percutaneously into the tendon (x3 proximal and x3 distal). We dissected around the Achillon jig to determine whether the needle and suture had punctured the sural nerve. We also documented the position of the sural nerve in relation to the Achilles tendon. Results. The mean horizontal distance from the Achilles tendon insertion to the sural nerve was 22.5mm (15.9mm–30.2mm). The mean vertical distance from the Achilles tendon insertion to the point where the sural nerve crosses the lateral border of the tendon was 96.1mm (77.4mm–134.9mm). In 4 out of 15 cadaveric specimens (27%) the sural nerve was punctured. In total, the sural nerve was punctured 6 times (twice in 2 specimens) in 90 needle passes (6.7%). Five out of the 6 punctures occurred when the Achillon device was inserted into the distal tendon portion with the most proximal hole being responsible for 3 of the punctures. Conclusions. The sural nerve displays a highly variable anatomical course and our findings highlight a significant risk of puncture during percutaneous Achilles tendon repair using the Achillon device. More studies are needed to clarify whether this risk equates to a significant clinical problem and whether a change in technique or instrumentation can decrease this risk

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. Supination-external rotation (SER) injuries make up 80% of all ankle fractures. SER stage 2 injuries (AITFL and Weber B) are considered stable. SER stage 3 injury includes disruption of the posterior malleolus (or PITFL). In SER stage 4 there is either medial malleolus fracture or deltoid injury too. SER 4 injuries have been considered unstable, requiring surgery. The deltoid ligament is a key component of ankle stability, but clinical tests to assess deltoid injury have low specificity. This study specifically investigates the role of the components of the deep deltoid ligament in SER ankle fractures. Aim. To investigate the effect of deep deltoid ligament injury on SER ankle fracture stability. Methods. Four matched pairs (8 specimens) were tested using a standardised protocol. Specimens were sequentially tested for stability when axially loaded with a custom rig with up to 750N. Specimens were tested with: ankle intact; lateral injury (AITFL and Weber B); additional posterior injury (PITFL); additional anterior deep deltoid; additional posterior deep deltoid; lateral side ORIF. Clinical photographs and radiographs were recorded. In addition, dynamic stress radiographs were performed after sectioning the deep deltoid and then after fracture fixation to assess tilt of the talus in eversion. Results. All specimens with an intact posterior deep deltoid ligament were stable when loaded and showed no talar tilt on dynamic assessment. Once the posterior deep deltoid ligament was sectioned there was instability in all specimens. Surgical stabilisation of the lateral side prevented talar shift but not talar tilt. Conclusion. If the posterior deep deltoid ligament is intact SER fractures may be managed without surgery in a plantigrade cast. Without immobilisation the talus may tilt, risking deltoid incompetence

Introduction. Early clinical examination combined with MRI following a high ankle sprain allows accurate diagnosis of syndesmosis instability. However, patients often present late, and for chronic injuries clinical assessment is less reliable. Furthermore, in many centres MRI may be not be readily available. The aims of the current study were to define MRI characteristics associated with syndesmosis instability, and to determine whether MRI patterns differed according to time from injury. Methods. Retrospectively, patients with an unstable ligamentous syndesmosis injury requiring fixation were identified from the logbooks of two fellowship trained foot and ankle surgeons over a five-year period. After exclusion criteria (fibula fracture or absence of an MRI report by a consultant radiologist), 164 patients (mean age 30.7) were available. Associations between MRI characteristics and time to MRI were examined using Pearson's chi-square tests or Fisher's exact tests (significance set at p< 0.05). Results. Overall, 100% of scans detected a syndesmosis injury if performed acutely (within 6 weeks of injury), falling to 83% if performed after 12 weeks (p=0.001). In the acute group, 93.5% of patients had evidence of at least one of either PITFL injury (78.7%), posterior malleolus bone oedema (60.2%), or a posterior malleolus fracture (15.7%). In 20% of patients with a posterior malleolus bone bruise or fracture, the PITFL was reported as normal. The incidence of posterior malleolus bone bruising and fracture did not significantly differ according to time. Conclusion. For unstable ligamentous syndesmosis injuries, MRI becomes less sensitive over time. Importantly, posterior malleolus bone oedema or fracture may be the only evidence of a posterior injury. Failure to recognise instability may lead to inappropriate management of the patient, long term pain and arthritis. We therefore advocate early MRI as it becomes more difficult to ‘grade’ the injury if delayed