The posterior malleolus of the ankle is the object of increasing attention, with considerable enthusiasm for CT scanning and surgical fixation, as expressed in a recent annotation in The Bone & Joint Journal. Undoubtedly, fractures with a large posterior malleolar fragment that allow posterior talar subluxation from the mortise are served better by fixation. However, in all other situations, the existing literature does not support this widespread change in practice. The available biomechanical evidence shows that the posterior malleolus has little part to play in the stability or contact stresses of the ankle joint. Radiographic studies have not shown that CT scanning offers helpful information on pathoanatomical classification, case selection, or prognosis, or that scanning improves the likelihood of an adequate surgical reduction. Clinical studies have not shown any improvement in patient outcome after surgical fixation, and have confirmed that the inevitable consequence of increased intervention is an increased rate of complications. A careful and thoughtful evaluation of indications, risks, and benefits of this fashionable concept is required to ensure that we are deploying valuable resources with efficacy, and that we do no harm. Cite this article: Bone Joint J 2018;100-B:566–9

The posterior malleolus component of a fracture of the ankle is important, yet often overlooked. Pre-operative CT scans to identify and classify the pattern of the fracture are not used enough. Posterior malleolus fractures are not difficult to fix. After reduction and fixation of the posterior malleolus, the articular surface of the tibia is restored; the fibula is out to length; the syndesmosis is more stable and the patient can rehabilitate faster. There is therefore considerable merit in fixing most posterior malleolus fractures. An early post-operative CT scan to ensure that accurate reduction has been achieved should also be considered. Cite this article: Bone Joint J 2017;99-B:1413–19

Aims

The primary aim of this study was to address the hypothesis that fracture morphology might be more important than posterior malleolar fragment size in rotational type posterior malleolar ankle fractures (PMAFs). The secondary aim was to identify clinically important predictors of outcome for each respective PMAF-type, to challenge the current dogma that surgical decision-making should be based on fragment size.

Aims

There has been an evolution recently in the management of unstable fractures of the ankle with a trend towards direct fixation of a posterior malleolar fragment. Within these fractures, Haraguchi type 2 fractures extend medially and often cannot be fixed using a standard posterolateral approach. Our aim was to describe the posteromedial approach to address these fractures and to assess its efficacy and safety.

It has previously been suggested that among unstable ankle fractures, the presence of a malleolar fracture is associated with a worse outcome than a corresponding ligamentous injury. However, previous studies have included heterogeneous groups of injury. The purpose of this study was to determine whether any specific pattern of bony and/or ligamentous injury among a series of supination-external rotation type IV (SER IV) ankle fractures treated with anatomical fixation was associated with a worse outcome.

We analysed a prospective cohort of 108 SER IV ankle fractures with a follow-up of one year. Pre-operative radiographs and MRIs were undertaken to characterise precisely the pattern of injury. Operative treatment included fixation of all malleolar fractures. Post-operative CT was used to assess reduction. The primary and secondary outcome measures were the Foot and Ankle Outcome Score (FAOS) and the range of movement of the ankle.

There were no clinically relevant differences between the four possible SER IV fracture pattern groups with regard to the FAOS or range of movement. In this population of strictly defined SER IV ankle injuries, the presence of a malleolar fracture was not associated with a significantly worse clinical outcome than its ligamentous injury counterpart. Other factors inherent to the injury and treatment may play a more important role in predicting outcome.

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

A number of classification systems exist for posterior malleolus fractures of the ankle. The reliability of these classification systems remains unclear. The primary aim of this study was to evaluate the reliability of three commonly utilised fracture classification systems of the posterior malleolus. 60 patients across 2 hospitals sustaining an unstable ankle fracture with a posterior malleolus fragment were identified. All patients underwent radiographs and computed tomography of their injured ankle. 9 surgeons including pre-ST3 level, ST3-8 level, and consultant level applied the Haraguchi, Rammelt, and Mason & Molloy classifications to these patients, at two timepoints, at least 4 weeks apart. The order was randomised between assessments. Inter-rater reliability was assessed using Fleiss’ kappa and 95% confidence intervals (CI). Intra-rater reliability was assessed using Cohen's Kappa and standard error (SE). Inter-rater reliability (Fleiss’ Kappa) was calculated for the Haraguchi classification as 0.522 (95% CI 0.490 – 0.553), for the Rammelt classification as 0.626 (95% CI 0.600 – 0.652), and the Mason & Molloy classification as 0.541 (95% CI 0.514 – 0.569). Intra-rater reliability (Cohen's Kappa) was 0.764 (SE 0.034) for the Haraguchi, 0.763 (SE 0.031) for the Rammelt, 0.688 (SE 0.035) for the Mason & Molloy classification. This study reports the inter-rater and intra-rater reliability for three classification systems for posterior malleolus fractures. Based on definitions by Landis & Koch (1977), inter-rater reliability was rated as ‘moderate’ for the Haraguchi and Mason & Molloy classifications; and ‘substantial’ for the Rammelt classification. Similarly, the intra-rater reliability was rated as ‘substantial’ for all three classifications

The February 2024 Trauma Roundup. 360. looks at: Posterior malleolus fractures: what about medium-sized fragments?; Acute or delayed total hip arthroplasty after acetabular fracture fixation?; Intrawound antibiotics reduce the risk of deep infections in fracture fixation; Does the VANCO trial represent real world patients?; Can a restrictive transfusion protocol be effective beyond initial resuscitation?; What risk factors result in avascular necrosis of the talus?; Pre-existing anxiety and mood disorders have a role to play in complex regional pain syndrome; Three- and four-part proximal humeral fractures at ten years

Aims. Paediatric triplane fractures and adult trimalleolar ankle fractures both arise from a supination external rotation injury. By relating the experience of adult to paediatric fractures, clarification has been sought on the sequence of injury, ligament involvement, and fracture pattern of triplane fractures. This study explores the similarities between triplane and trimalleolar fractures for each stage of the Lauge-Hansen classification, with the aim of aiding reduction and fixation techniques. Methods. Imaging data of 83 paediatric patients with triplane fractures and 100 adult patients with trimalleolar fractures were collected, and their fracture morphology was compared using fracture maps. Visual fracture maps were assessed, classified, and compared with each other, to establish the progression of injury according to the Lauge-Hansen classification. Results. Four stages of injury in triplane fractures, resembling the adult supination external rotation Lauge-Hansen stages, were observed. Stage I consists of rupture of the anterior syndesmosis or small avulsion of the anterolateral tibia in trimalleolar fractures, and the avulsion of a larger Tillaux fragment in triplanes. Stage II is defined as oblique fracturing of the fibula at the level of the syndesmosis, present in all trimalleolar fractures and in 30% (25/83) of triplane fractures. Stage III is the fracturing of the posterior malleolus. In trimalleolar fractures, the different Haraguchi types can be discerned. In triplane fractures, the delineation of the posterior fragment has a wave-like shape, which is part of the characteristic Y-pattern of triplane fractures, originating from the Tillaux fragment. Stage IV represents a fracture of the medial malleolus, which is highly variable in both the trimalleolar and triplane fractures. Conclusion. The paediatric triplane and adult trimalleolar fractures share common features according to the Lauge-Hansen classification. This highlights that the adolescent injury arises from a combination of ligament traction and a growth plate in the process of closing. With this knowledge, a specific sequence of reduction and optimal screw positions are recommended. Cite this article: Bone Joint J 2024;106-B(9):1008–1014

Aims. Involvement of the posterior malleolus in fractures of the ankle probably adversely affects the functional outcome and may be associated with the development of post-traumatic osteoarthritis. Anatomical reduction is a predictor of a successful outcome. The purpose of this study was to describe the technique and short-term outcome of patients with trimalleolar fractures, who were treated surgically using a posterolateral approach in our hospital between 2010 and 2014. Patients and Methods. The study involved 52 patients. Their mean age was 49 years (22 to 79). There were 41 (79%) AO 44B-type and 11 (21%) 44C-type fractures. The mean size of the posterior fragment was 27% (10% to 52%) of the tibiotalar joint surface. Results. Reduction was anatomical in all patients with a residual step in the articular surface of ≤ 1 mm. In nine of the C-type fractures (82%), the syndesmosis was stable after fixation of the posterior fragment and a syndesmosis screw was not required. Apart from one superficial wound infection, there were no wound healing problems. At a mean radiological follow-up of 34 weeks (seven to 131), one patient with a 44C-type fracture had widening of the syndesmosis which required further surgery. Conclusion. We conclude that the posterolateral surgical approach to the ankle gives adequate access to the posterior malleolus, allowing its anatomical reduction and stable fixation: it has few complications. Take home message: Fixation of the posterior malleolus in trimalleolar fractures can be easily done via the posterolateral approach whereby anatomical reduction and stable fixation can be reached due to adequate visualisation of the fracture. Cite this article: Bone Joint J 2016;98-B:812–17

The December 2023 Trauma Roundup. 360. looks at: Distal femoral arthroplasty: medical risks under the spotlight; Quads repair: tunnels or anchors?; Complex trade-offs in treating severe tibial fractures: limb salvage versus primary amputation; Middle-sized posterior malleolus fractures – to fix?; Bone transport through induced membrane: a randomized controlled trial; Displaced geriatric femoral neck fractures; Risk factors for reoperation to promote union in 1,111 distal femur fractures; New versus old – reliability of the OTA/AO classification for trochanteric hip fractures; Risk factors for fracture-related infection after ankle fracture surgery

The optimal management of rotationally-unstable ankle fractures involving the posterior malleolus remains controversial. Standard practice involves trans-syndesmotic fixation (TSF), however, recent attention has been paid to the indirect reduction of the syndesmosis by repairing small posterior malleolar fracture avulsion fragments, if present, using open reduction internal fixation. Posterior malleolus fixation (PMF) may obviate the need for TSF. Given the limited evidence and diversity in surgical treatment options for rotationally-unstable ankle fractures with ankle syndesmosis and posterior malleolar involvement, we sought to assess the research landscape and identify knowledge gaps to address with future clinical trials. We performed a scoping review to investigate rotational ankle fractures with posterior malleolar involvement, utilizing the framework originally described by Arksey and O'Malley. We searched the English language literature using the Ovid Medline and Embase databases. All study types investigating rotationally-unstable ankle fractures with posterior malleolus involvement were categorized into defined themes and descriptive statistics were used to summarize methods and results of each study. A total of 279 articles published from 1988 to 2018 were reviewed, and 70 articles were included in the final analysis. The literature consists of studies examining the surgical treatment strategies for PMF (n=21 studies, 30%), prognosis of rotational ankle fractures with posterior malleolar involvement (n=16 studies, 23%), biomechanics and fracture pattern of these injuries (n=13 studies, 19%), surgical approach and pertinent anatomy for fixation of posterior malleolus fractures (n=12 studies, 17%), and lastly surgical treatment of syndesmotic injuries with PMF compared to TSF (n=4 studies, 6%). Uncontrolled case series of single treatment made up the majority of all clinical studies (n=44 studies, 63%), whereas controlled study designs were the next most common (n=16 studies, 23%). Majority of research in this field has been conducted in the past eight years (n=52 studies, 74%). Despite increasing concern and debate among the global orthopaedic community regarding rotationally-unstable ankle fractures with syndesmosis and posterior malleolar involvement, and an increasing trend towards PMF, optimal treatment remains unclear when comparing TSF to PMF. Current research priorities are to (1) define the specific injury pattern for which PMF adequately stabilizes the syndesmosis, and (2) conduct a randomized clinical trial comparing PMF to TSF with the assistance of the orthopaedic community at large with well-defined clinical outcomes

Introduction. Diaphyseal tibial fractures account for approximately 1.9% of adult fractures. Studies have demonstrated a high proportion have ipsilateral occult posterior malleolus fractures. We hypothesize that this rotational element will be highlighted using the Mason & Molloy Classification. Materials and Methods. A retrospective review of a prospectively collected database was performed at Liverpool University Hospitals NHS Foundation Trust between 1/1/2013 and 9/11/2020. The inclusion criteria were patients over 16, with a diaphyseal tibial fracture, who underwent a CT. The Mason and Molloy posterior malleolus fracture classification system was used. Results. 764 diaphyseal tibial fractures were analysed, 300 had a CT. 127 were intra-articular fractures. 83 (27.7%) were classifiable using Mason and Molloy classification. There were 8 type 1 (9.6%), 43 type 2 (51.8%), 5 type 2B (6.0%) and 27 type 3 (32.5%). 90.4% (n=75) of the posterior malleolar fractures, were undisplaced. The majority of PM fractures occurred in type 42A1 (65 of 142 tibia fractures) and 42B1 (11 of 16). Conclusions. Most PM fractures occurred after a rotational mechanism. Unlike, the PM fractures of the ankle, the majority of PM fractures associated with tibia fractures are undisplaced. We theorise that unlike the force transmission in ankle fractures where the rotational force is in the axial plane in a distal-proximal direction, in the PM fractures related to fractures of the tibia, the rotational force in the axial plane progresses from proximal-distal. Therefore, the force transmission which exits posteriorly, finally dissipates the force and thus unlikely to displace

Aims. The ideal management of acute syndesmotic injuries in elite athletes is controversial. Among several treatment methods used to stabilize the syndesmosis and facilitate healing of the ligaments, the use of suture tape (InternalBrace) has previously been described. The purpose of this study was to analyze the functional outcome, including American Orthopaedic Foot & Ankle Society (AOFAS) scores, knee-to-wall measurements, and the time to return to play in days, of unstable syndesmotic injuries treated with the use of the InternalBrace in elite athletes. Methods. Data on a consecutive group of elite athletes who underwent isolated reconstruction of the anterior inferior tibiofibular ligament using the InternalBrace were collected prospectively. Our patient group consisted of 19 elite male athletes with a mean age of 24.5 years (17 to 52). Isolated injuries were seen in 12 patients while associated injuries were found in seven patients (fibular fracture, medial malleolus fracture, anterior talofibular ligament rupture, and posterior malleolus fracture). All patients had a minimum follow-up period of 17 months (mean 27 months (17 to 35)). Results. All patients returned to their pre-injury level of sports activities. One patient developed a delayed union of the medial malleolus. The mean return to play was 62 days (49 to 84) for isolated injuries, while the patients with concomitant injuries returned to play in a mean of 104 days (56 to 196). The AOFAS score returned to 100 postoperatively in all patients. Knee-to-wall measurements were the same as the contralateral side in 18 patients, while one patient lacked 2 cm compared to the contralateral side. Conclusion. This study suggests the use of the InternalBrace in the management of unstable syndesmotic injuries offers an alternative method of stabilization, with good short-term results, including early return to sports in elite athletes. Cite this article: Bone Joint J 2022;104-B(1):68–75

Management of complex posterior malleolar fractures requires a detailed appreciation of ligamentous and bony anatomy for optimal fracture fixation and restoration of articular congruency. Pre operative planning is vitally important to determine the surgical strategy for complex ankle fractures. We evaluated pre operative planning strategy pre and post implementation of BOAST 12 guidelines (2016) focussing on pre operative CT scans prior to definitive fixation at a major trauma centre. A multi-surgeon retrospective review of prospectively collected data from 2013 to 2018 was performed at a major trauma centre. Patients who had sustained a posterior malleolar fracture and definitive fixation were identified. Information was collated from PICS, PACS, the trauma database and operative notes. 134 patients were identified over a 5 year period who had sustained a posterior malleolar fracture and had definitive fixation. (Pre BOAST guidelines = 61, Post BOAST guidelines = 73). Prior to the implementation of BOAST guidelines ¼ with posterior malleolar fractures did not have a pre operative CT scan (15/61). Post implementation of BOAST 12 90% (66/73)patients with fixation of posterior malleolus fractures had a pre operative CT scan. Posterior malleolus surgery most commonly took place In patients between 18–30 years. Following implantation of BOAST 12 guidelines there was a 15% increase in pre operative CT scanning for ‘complex ankle fractures'. Changes in national guidelines have heavily influenced pre operative planning strategy for ankle fractures at University Hospitals Birmingham. A detailed appreciation of fracture pattern pre operatively helps guide surgical strategy

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

The aim of this study was to evaluate the long-term outcomes of patients who had sustained an unstable ankle fracture with a posterior malleolus fracture (PMF) and without (N-PMF). Adult patients presenting to a single academic trauma centre in Edinburgh, UK, between 2009 and 2012 with an unstable ankle fracture requiring surgery were identified. The primary outcome measure was the Olerud Molander Ankle Score (OMAS). Secondary measures included Euroqol-5D-3L Index (Eq5D3L), Euroqol-5D-VAS and Manchester Oxford Foot Questionnaire (MOXFQ). There were 304 patients in the study cohort. The mean age was 49.6 years (16.3–78.3) and 33% (n=100) male and 67% (n=204) female. Of these, 67% (n=204) had a PMF and 33% did not (n=100). No patient received a computed tomography (CT) scan pre-operatively. Only 10% of PMFs (22/204) were managed with internal fixation. At a mean of 13.8 years (11.3 – 15.3) the median OMAS score was 85 (Interquartile Range 60 – 100). There was no difference in OMAS between the N-PMF and PMF groups (85 [56.25 – 100] vs 85 [61.25 – 100]; p = 0.580). There was also no difference for MOXFQ (N-PMF 7 [0 – 36.75] vs PMF 8 [0–38.75]; p = 0.643), the EQ5D Index (N-PMF 0.8 [0.7 – 1] vs PMF 0.8 [0.7 – 1]; p = 0.720) and EQ5D VAS (N-PMF 80 [70 – 90] vs PMF 80 [60 – 90]; p = 0.224). The presence of a PMF does not affect the long-term patient reported outcomes in patients with a surgically managed unstable ankle fracture

Treatment of posterior malleolar (PM) ankle fractures remain controversial. Despite increasing recommendation for small PM fragment fixation, high quality evidence demonstrating improved clinical outcomes over the unfixated PM is limited. We describe the medium-to-long term clinical and radiographical outcomes in younger adult patients with PM ankle fractures managed without PM fragment fixation. A retrospective cohort study of patients aged 18–55 years old admitted under our orthopaedic unit between 1st of April 2009 and 31st of October 2013 with PM ankle fractures was performed. Inclusion criteria were that all patients must mobilise independently pre-trauma, have no pre-existing ankle pathologies, and had satisfactory bimalleolar and syndesmotic stabilisation. Open fractures, talar fractures, calcaneal fractures, pilon fractures, subsequent re-injury and major complications were excluded. All PM fragments were unfixated. Clinical outcomes were evaluated using Foot and Ankle Ability Measure (FAAM) with activities of daily living (ADL) and sports subscale, visual analogue scale (VAS) and patient satisfaction ratings. Osteoarthrosis was assessed using modified Kellgren-Lawrence scale on updated weightbearing ankle radiographs. 61 participants were included. Mean follow-up was 10.26 years. Average PM size was 16.19±7.39%. All participants were evaluated for clinical outcomes, demonstrating good functional outcomes (FAAM-ADL 95.48±7.13; FAAM-Sports 86.39±15.52) and patient satisfaction (86.16±14.42%), with minimal pain (VAS 1.13±1.65). Radiographical outcomes were evaluated in 52 participants, showing no-to-minimal osteoarthrosis in 36/52 (69.23%), mild osteoarthrosis in 14/52 (26.92%) and moderate osteoarthrosis in 2/52 (3.85%). Clinical outcomes were not associated with PM fragment size, post-reduction step-off, dislocation, malleoli fractured or syndesmotic injury. PM step-off and dislocation were associated with worse radiographical osteoarthrosis. Other published medium-to-long term studies reported overall good outcomes, with no differences after small fragment fixation. The unfixated smaller posterior malleolus fragment demonstrated overall satisfactory clinical and radiographical outcomes at 10-year follow-up and may be considered a valid treatment strategy

Introduction. Diaphyseal tibial fractures account for approximately 1.9% of adult fractures. Several studies demonstrate a high proportion of diaphyseal tibial fractures have ipsilateral occult posterior malleolus fractures, this ranges from 22–92.3%. Materials and Methods. A retrospective review of a prospectively collected database was performed at Liverpool University Hospitals NHS Foundation Trust between 1/1/2013 and 9/11/2020. The inclusion criteria were patients over 16, with a diaphyseal tibial fracture and who underwent a CT. The articular fracture extension was categorised into either posterior malleolar (PM) or other fracture. Results. 764 fractures were analysed, 300 had a CT. There were 127 intra-articular fractures. 83 (65.4%) cases were PM and 44 were other fractures. On univariate analysis for PM fractures, fibular spiral (p=.016) fractures, no fibular fracture(p=.003), lateral direction of the tibial fracture (p=.04), female gender (p=.002), AO 42B1 (p=.033) and an increasing angle of tibial fracture. On multivariate regression analysis a high angle of tibia fracture was significant. Other fracture extensions were associated with no fibular fracture (p=.002), medial direction of tibia fracture (p=.004), female gender (p=.000), and AO 42A1 (p=.004), 42A2 (p=.029), 42B3 (p=.035) and 42C2 (p=.032). On multivariate analysis, the lateral direction of tibia fracture, and AO classification 42A1 and 42A2 were significant. Conclusions. Articular extension happened in 42.3%. A number of factors were associated with the extension, however multivariate analysis did not create a suitable prediction model. Nevertheless, rotational tibia fractures with a high angle of fracture should have further investigation with a CT

Purpose. The anterior inferior tibiofibular ligament (AiTFL) is the primary lateral ligamentous stabilizer of the ankle syndesmosis. Current syndesmosis repair techniques traverse the tibia and fibula, but do not anatomically reconstruct the AiTFL. We compared a novel AiTFL anatomic repair technique (ART) to rigid syndesmosis screw fixation (SCREW). Method. Twelve cadaveric below knee specimens were compared radiographically and using a biomechanical testing protocol. All specimens underwent a CT scan of the ankle joint prior to testing. Next, the AiTFL, interosseous membrane and deltoid ligament were sectioned, and the posterior malleolus osteotomized, to recreate a trimalleolar-equivalent ankle fracture. The posterior malleolus was repaired with the posterior ligamentous insertions intact and functional (PMALL). Ankles were examined under fluoroscopy with an external rotation stress exam and the medial clear space (MCS) measured. Specimens were then randomized to receive either a conventional syndesmosis screw (SCREW), or the novel anatomic repair technique (ART). External rotation stress fluoroscopy was repeated. A second CT was completed and the fibular position compared to the pre-injury CT. Each specimen was then loaded in external rotation until failure using a custom biomechanical jig. Results. The MCS during stress examination increased by 1.04 0.31mm in the PMALL group. MCS increased significantly less at only 0.300.07mm (p=0.002) in the ART group. The SCREW fixation method demonstrated a delta MCS of 0.280.16mm (p=0.008). Post repair CT showed that 33% of specimens were subluxed from the SCREW group compared to 0% for the ART. Mean torque at failure for ART was 24.85.5Nm compared to 16.85.8Nm for SCREW (p=0.01). Conclusion. Repair of the posterior malleolus alone demonstrated a greater than 1mm of medial clear space widening and is not sufficient to re-establish syndesmotic stability. Addition of the ART or SCREW technique restored syndesmotic stability. None of the ART specimens demonstrated fibular subluxation, while 33% of SCREW specimens were subluxed anteriorly on CT. Biomechanical strength of the ART was found to be greater than that of rigid screw fixation