Introduction. In this cohort study, the TightRope® fixation technique has been compared with the traditional screw fixation for ankle syndesmosis injuries, with respect to the accuracy of the syndesmotic reduction and their clinical correlation. Patients and Methods. This cohort study included consecutive patients treated for ankle syndesmotic diastases between July 2007 and June 2009. Single slice axial CT scans of both the ankles together were performed at the level of syndesmosis, 1 cm above the tibial plafond. More than 2 mm widening of syndesmosis as compared to normal contra-lateral ankle was considered as significant malreduction. Clinical outcomes were measured using AOFAS and FADI Scores. Results. Forty-six out of 55 eligible patients attended for the study. Twenty three patients were in the tightRope group and 23 in the syndesmosis screw group. Mean follow-up was 2.5 (1.5–3.5) years. Average age was 41.6 years in tightrope group and 39.8 years in syndesmosis screw group. The mean width of normal syndesmosis was 4.01 + 0.89 mm. In tightRope group the mean width of syndesmosis was 4.37 + 1.12 mm (t-test, p = 0.30) as compared to 5.16 + 1.92 mm in screw group (t-test, p = 0.01). Five (21.7%) out of 23 ankles in screw group had syndesmotic mal reduction, while none of the tightRope group showed mal-reduction on CT scans (fisher's exact test, p = 0.04). There was no significant difference in mean post operative AOFAS score (89.56 and 86.52) and FADI score (82.42 and 81.22) between two groups. Conclusion. The results of this study indicate that tightRope provides more accurate method of syndesmosis stabilization as compared with screw fixation. Syndesmosis malreduction is the most important independent predictor of clinical outcomes; therefore care should be taken to reduce the syndesmosis accurately

Classical AO teaching recommends that a syndesmosis screw should be inserted at 25 to 30 degree angle to the coronal plane of the ankle. In practice accurately judging the 25/30 degree angle can be difficult, and there are several reports based on post operative CT scans demonstrating that a significant minority of patients have poorly operatively reduced syndesmotic injuries. The CT scans of 200 normal ankles in one hundred individuals which had been performed as part a CT angiogram were retrospectively examined. The centroid of the fibula and tibia in the axial plane 15mm proximal to the talar dome was calculated. Since a force vector between the centroid of the fibula and the tibia in the axial plane should not displace the fibula relative to the tibia, a line connecting the two centroids was therefore postulated to be the ideal syndesmosis line, and also the optimum position in which to place a compression clamp after reducing the syndesmosis. Where this ideal line passed through the lateral border of the fibula, and through the medial malleolus was then noted. The ideal syndesmosis line was shown to pass through the fibula with in 2mm of the lateral cortical apex of the fibula, and the anterior half of the medial malleolus in 100% of the ankles studied. The results support the concept that in the operatively reduced syndesmosis, the anterior half of the medial malleolus can be used as a reliable guide for aiming the syndesmosis drill hole, provided that the fibular entry point is at or adjacent the lateral fibular apex. The corollary of these findings is that a screw inserted through a plate on the standard antero-lateral border of the fibula, or a plate in the anti-glide position posteriorly, cannot lie in the centroidal axis of the ankle

Background: Injuries to ankle joint consist 12% of visits to emergency departments. In spite of the common occurrence of ankle sprain, syndesmosis injuries are rare, but very debilitating and frequently misdiagnosed. Methods: Among 100 patients with ankle sprain we evaluated the incidence of syndesmosis sprain by MRI of the ankle. Adults who had acute ankle sprain with no fracture and examined on the same day that injury had took place were being included in the survey. Results: Out of 100 patients with ankle injury, four had syndesmosis sprain. Three patients had partial tear of syndesmotic complex and one had complete tear. All injuries occurred in sports except one which had happened in an accident, and two of the patients were athletes. Anterior inferior tibiofibular ligament was the most common ruptured ligament. Conclusions: We reported a four-percent incidence of this injury. Our high rate of this injury emphasized on the fact that all suspicious cases should go under more accurate investigation not to miss this diagnosis

Introduction. Aneurysmal bone cysts commonly found in lower limbs are locally aggressive masses that can lead to bony erosion, instability and fractures. This has major implications in the lower limbs especially in paediatric patients, with potential growth disturbance and deformity. In this case series we describe radical aneurysmal bone cyst resection and lower limb reconstruction using cable transport and syndesmosis preservation. Materials & Methods. Case 1 - A 12-year-old boy presented with a two-week history of atraumatic right ankle pain. An X-ray demonstrated a distal tibia metaphyseal cyst confirmed on biopsy as an aneurysmal bone cyst. The cyst expanded on interval X-rays from 5.5cm to 8.5cm in 9 weeks. A wide-margin en-bloc resection was performed leaving a 13.8cm tibial defect. A cable transport hexapod frame and a proximal tibial osteotomy was performed, with syndesmosis screw fixation. The transport phase lasted 11 months. While in frame, the boy sustained a distal femur fracture from a fall. The femur and the docking site were plated at the same sitting and frame removed. At one-year post-frame removal he is pain-free, with full ankle dorsiflexion but plantarflexion limited to 25 degrees. He has begun graduated return to sport. Results. Case 2 - A 12-year-old girl was referred with a three-month history of lateral left ankle swelling. X-ray demonstrated an aneurysmal bone cyst in the distal fibula metaphysis. The cyst grew from 4.2 × 2.3cm to 5.2 × 3.32cm in 2 months. A distal fibula resection (6.2cm) with syndesmosis fixation and hexapod cable transport frame were undertaken. The frame was in situ for 13 weeks and during this time she required an additional osteotomy for premature consolidation and had one pin site infection. After 13 weeks a second syndesmosis screw was placed, frame removed, and a cast applied. 3 months later she had fibular plating, BMAC and autologous iliac crest bone graft for slow union. At 3 years post-operative she has no evidence of recurrence, is pain-free and has no functional limitation. Conclusions. We describe two cases of ankle syndesmosis preservation using cable transport for juxta-articular aneurysmal bone cysts. This allows wide resection to prevent recurrence while also preserving primary ankle stability and leg length in children. Both children had a minor complication, but both had an excellent final outcome. Cable bone transport and prophylactic syndesmosis stabilization allows treatment of challenging juxta-articular aneurysmal bone cysts about the ankle. These techniques are especially useful in large bone defects

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

Abstract. Objectives. The syndesmosis joint, located between the tibia and fibula, is critical to maintaining the stability and function of the ankle joint. Damage to the ligaments that support this joint can lead to ankle instability, chronic pain, and a range of other debilitating conditions. Understanding the kinematics of a healthy joint is critical to better quantify the effects of instability and pathology. However, measuring this movement is challenging due to the anatomical structure of the syndesmosis joint. Biplane Video Xray (BVX) combined with Magnetic Resonance Imaging (MRI) allows direct measurement of the bones but the accuracy of this technique is unknown. The primary objective is to quantify this accuracy for measuring tibia and fibula bone poses by comparing with a gold standard implanted bead method. Methods. Written informed consent was given by one participant who had five tantalum beads implanted into their distal tibia and three into their distal fibula from a previous study. Three-dimensional (3D) models of the tibia and fibula were segmented (Simpleware Scan IP, Synopsis) from an MRI scan (Magnetom 3T Prisma, Siemens). The beads were segmented from a previous CT and co-registered with the MRI bone models to calculate their positions. BVX (125 FPS, 1.25ms pulse width) was recorded whilst the participant performed level gait across a raised platform. The beads were tracked, and the bone position of the tibia and fibula were calculated at each frame (DSX Suite, C-Motion Inc.). The beads were digitally removed from the X-rays (MATLAB, MathWorks) allowing for blinded image-registration of the MRI models to the radiographs. The mean difference and standard deviation (STD) between bead-generated and image-registered bone poses were calculated for all degrees of freedom (DOF) for both bones. Results. The absolute mean tibia and fibula bone position differences (Table 1) between the bead and BVX poses were found to be less than 0.5 mm for both bones. The bone rotation differences were found to be less than 1° for all axes except for the fibula Z axis rotation which was found to be 1.46°. One study. 1. has reported the kinematics of the syndesmosis joint and reported maximum ranges of motion of 9.3°and translations of 3.3mm for the fibula. The results show that the accuracy of the methodology is sufficient to quantify these small movements. Conclusions. BVX combined with MRI can be used to accurately measure the syndesmosis joint. Future work will look at quantifying the accuracy of the talus to provide further understanding of normal ankle kinematics and to quantify the kinematics across a healthy population to act as a comparator for future patient studies. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Nearly one quarter of ankle fractures have a recognized syndesmosis injury. An intact syndesmosis ligament complex stabilizes the distal tibio-fibular joint while allowing small, physiologic amounts of relative motion. When injured, malreduction of the syndesmosis has been found to be the most important independent factor that contributes to inferior functional outcomes. Despite this, significant variability in surgical treatment remains. This may be due to a poor understanding of normal dynamic syndesmosis motion and the resultant impact of static and dynamic fixation on post-injury syndesmosis kinematics. As the syndesmosis is a dynamic structure, conventional CT static images do not provide a complete picture of syndesmosis position, giving potentially misleading results. Dynamic CT technology has the ability to image joints in real time, as they are moved through a range-of-motion (ROM). The aim of this study was to determine if syndesmosis position changes significantly throughout ankle range of motion, thus warranting further investigation with dynamic CT. This is an a priori planned subgroup analysis of a larger multicentre randomized clinical trial, in which patients with AO-OTA 44-C injuries were randomized to either Tightrope or screw fixation. Bilateral ankle CT scans were performed at 1 year post-injury, while patients moved from maximal dorsiflexion (DF) to maximal plantar flexion (PF). In the uninjured ankles, three measurements were taken at one cm proximal to the ankle joint line in maximal DF and maximal PF: Anterior (ASD), middle (MSD), and posterior (PSD) syndesmosis distance, in order to determine normal syndesmosis position. Paired samples t-tests compared measurements taken at maximal DF and maximal PF. Twelve patients (eight male, six female) were included, with a mean age of 44 years (±13years). The mean maximal DF achieved was 1-degree (± 7-degrees), whereas the mean maximal PF was 47-degrees (± 8-degrees). The ASD in DF was 3.0mm (± 1.1mm) versus 1.9mm (± 0.8mm) in PF (p<0.01). The MSD in DF was 3.3mm (±1.1mm) versus 2.3mm (±0.9mm) in PF (p<0.01). The PSD in DF was 5.3mm (±1.5mm) versus 4.6mm (±1.9mm) in PF (p<0.01). These values are consistent with the range of normal parameters previously reported in the literature, however this is the first study to report the ankle position at which these measurements are acquired and that there is a significant change in syndesmosis measurements based on ankle position. Normal syndesmosis position changes in uninjured ankles significantly throughout range of motion. This motion may contribute to the variation in normal anatomy previously reported and controversies surrounding quantifying anatomic reduction after injury, as the ankle position is not routinely standardized, but rather static measurements are taken at patient-selected ankle positions. Dynamic CT is a promising modality to quantify normal ankle kinematics, in order to better understand normal syndesmosis motion. This information will help optimize assessment of reduction methods and potentially improve patient outcomes. Future directions include side-to-side comparison using dynamic CT analysis in healthy volunteers

Flexible fixation techniques combined with anatomic (open) syndesmosis reduction have demonstrated improved functional outcomes and rates of malreduction. Suture-button devices allow physiologic motion of the syndesmosis without need for implant removal, which may lower the risk of recurrent syndesmotic diastasis. There is limited longer-term assessment of the maintenance of reduction between static and flexible syndesmotic fixation using bilateral ankle CT evaluation. This is an a priori planned subgroup analysis of a multi-centre, randomized clinical trial comparing static syndesmosis fixation (two 3.5 mm screws) with flexible fixation (single knotless Tightrope) for patients with AO- OTA 44-C injuries. Patients who completed bilateral ankle CT scans at 3- and 12-month follow-up were included. The primary outcome measure was syndesmotic malreduction based on bilateral ankle CT scans, using the uninjured, contralateral ankle as a control. Anterior (ASD), middle (MSD), and posterior (PSD) syndesmosis distance were calculated to measure syndesmosis reduction. Secondary outcomes included re-operation, adverse events and functional outcomes including the EQ5D, Olerud-Molander Ankle Score (OM), Foot and Ankle Disability Index (FADI), and Work Productivity Activity Impairment Questionnaire (WPAI). Paired samples t-tests were used to compare injured to control ankles (R, v 3.5.1). 42 patients (24 Group S, 18 Group T) were included. ASD for Group T was 5.22mm (95%CI 4.69–5.77) at 3 months compared to 4.26mm (95%CI 3.82–4.71; p=0.007) in controls and 5.38mm (95%CI 4.72–6.04) at 12 months compared to 4.44mm (95%CI 3.73–5.16; p=0.048) in controls. ASD for Group S was 4.63mm (95%CI 4.17– 5.10) at 3 months compared to 4.67mm (95%CI 4.24–5.10; p=0.61) in controls, but significantly increased to 5.73mm (95%CI 4.81–6.66) at 12 months compared to 4.65mm (95%CI 4.15–5.15; p=0.04) in controls. MSD results were similar; Group T had a larger MSD than control ankles at 3 months (p=0.03) and 12 months (p=0.01), while the MSD in Group S was not different at 3 months (p=0.80) but increased at 12 months (p=<0.01). 88% (21/24) of Group S had broken or removed screws by 12 months. Unplanned re-operation was 15% in Group S and 4% in Group T (p=0.02), with an overall re-operation rate of 30% in Group S. There was no significant difference between treatment groups for EQ-5D, OM, FADI or WPAI at 3- or 12-month follow-up. Tightrope fixation resulted in greater diastasis of the ASD and MSD compared to contralateral, uninjured ankles at 3- and 12-months post-fixation. Group S initially had syndesmotic reduction similar to control ankles, but between 3- and 12-months post-fixation, there was significantly increased syndesmosis diastasis compared to controls. The majority of Group S (88%) had either broken screws or scheduled screw removal, which may explain the increased tibio-fibular diastasis seen at 12-months

Syndesmotic ankle injuries are present in one fourth of all ankle trauma and may lead to chronic syndesmotic instability as well as posttraumatic ankle osteoarthritis. The main challenge remains distinguishing them from other types of ankle trauma. Currently, the patient's injured and non-injured ankles are compared using plain radiographs to determine pathology. However, these try to quantify 3D displacement using 2D measurements techniques and it is unknown to what extent the 3D configuration of the normal ankle syndesmosis is symmetrical. We aimed to assess the 3D symmetry of the normal ankle syndesmosis between the right and left side in a non- and weightbearing CT. In this retrospective comparative cohort study, patients with a bilateral non-weightbearing CT (NWBCT; N=28; Mean age=44, SD=17.4) and weight-bearing CT (WBCT; N=33; Mean age=48 years; SD=16.3) were analyzed. Consecutive patients were included between January 2016 and December 2018 when having a bilateral non-weightbearing or weightbearing CT of the foot and ankle. Exclusion criteria were the presence of hindfoot pathology and age less than 18 years or greather than 75 years. CT images were segmented to obtain 3D models. Computer Aided Design (CAD) operations were used to fit the left ankle on top of the right ankle. The outermost point of the apex of the lateral malleolus (AML), anterior tubercle (ATF) and posterior tubercle (PTF) were computed. The difference in the coordinates attached to these anatomical landmarks of the left distal fibula in the ankle syndesmosis with respect to right were used to quantify symmetry. A Cartesian coordinate system was defined based on the tibia to obtain the direction of differences in all six degrees of freedom. Statistical analysis was performed using the Mann-Whitney U test to allow comparison between measurements from a NWBCT and WBCT. Reference values were determined for each 3D measurement in a NWBCT and WBCT based on their 2SD. The highest difference in translation could be detected in the anterior-posterior direction (Mean AP. NWBCT. = −0.01mm; 2SD=3.43/Mean AP. WBCT. =−0.1mm; 2SD=2.3) and amongst rotations in the external direction (Mean AP. NWBCT. =−0.3°; 2SD=6.7/Mean AP. WBCT. =-0,2°; 2SD=5.2). None of these differences were statistically significant in the normal ankle syndesmosis when obtained from a NWBCT compared to a WBCT (P>0.05). This study provides references values concerning the 3D symmetry of the normal ankle syndesmosis in weightbearing and non-weightbearing CT-scans. These novel data contribute relevantly to previous 2D radiographic quantifications. In clinical practice they will aid in distinguishing if a patient with a syndesmotic ankle lesion differs from normal variance in syndesmotic ankle symmetry

The incisura fibularis (IF) provides intrinsic stability to the ankle joint complex by interlocking the distal tibia and fibula. Despite a high frequency of ligamentous ankle injuries, scant attention has been given to the morphology of the IF morphology incisura fibularis in the onset and development of these lesions. Therefore, we systematically reviewed the relation between ligamentous ankle disorders and the morphometrics of the IF. A systematic literature search was conducted on following databases: PubMed, Embase and Web of Science. Search terms consisted of ‘ankle trauma’, ‘ankle injury’, ‘ankle sprain’, ‘ankle fracture’, ‘tibiofibular’, ‘fibular notch’, ‘fibular incisura’, ‘incisura fibularis’, ‘morphometric analysis’, ‘ankle syndesmosis’, ‘syndesmotic stability’. The evaluation instrument developed by Hawker et al. was used to assess the quality of the selected studies. This protocol was performed according to the PRISMA guidelines and is registered on PROSPERO (CRD42021282862). Nineteen studies were included and consisted of prospective cohort (n=1), retrospective comparative (n=10), and observational (n=8) study design. Comparative studies have found certain morphological characteristics in patients with ankle instability. Several studies (n=5) have correlated a shallow IF depth with a higher incidence of ankle injury. A significant difference has also been found concerning the incisura height and angle (n=3): a shorter incisura and more obtuse angle have been noted in patients with ankle sprains. The mean Hawker score was 28 out of 36 (range=24-31). A shallower IF is associated with ligamentous ankle lesions and might be due to a lower osseous resistance against tibiofibular displacement. However, these results should be interpreted in light of moderate methodological quality and should always be correlated with clinical findings. Further prospective studies are needed to further assess the relation between the incisura morphometrics and ligamentous disorders of the ankle joint. Keywords: ankle instability, ankle injury, incisura fibularis, fibular notch, tibiofibular morphometrics, ankle syndesmosis

The syndesmosis ligament complex stabilizes the distal tibiofibular joint, while allowing for the subtle fibular motion that is essential for ankle congruity. Flexible fixation with anatomic syndesmosis reduction results in substantial improvements in functional outcomes. New dynamic CT technology allows real-time imaging, as the ankle moves through a range of motion. The aim of this study was to determine if dynamic CT analysis is a feasible method for evaluating syndesmosis reduction and motion following static and flexible syndesmosis fixation. This is a subgroup analysis of a larger multicenter randomized clinical trial, in which patients with AO 44-C injuries were randomized to either Tightrope (one knotless Tightrope, Group T) or screw fixation (two 3.5-mm cortical screws, Group S). Surgical techniques and rehabilitation were standardized. Bilateral ankle CT scans were performed at one year post-injury, while patients moved from maximal dorsiflexion (DF) to maximal plantar flexion (PF). Three measurements were taken at one cm proximal to the ankle joint line in maximal DF and maximal PF: anterior, midpoint, and posterior tibiofibular distances. T-tests compared Group T and Group S, and injured and uninjured ankles in each group. Fifteen patients (six Group T [three male], nine Group S [eight male]) were included. There was no difference for mean age (T = 42.8 ± 14.1 years, S = 37 ± 12.6, P = 0.4) or time between injury and CT scan (T = 13 ± 1.8 months, S = 13.2 ± 1.8, P = 0.8). Of note in Group S, seven of nine patients had at least one broken screw and one additional patient had screws removed by the time of their dynamic CT. There was no significant difference between treatment groups for tibiofibular distance measurements in maximal PF or DF. Group T showed no significant difference between the injured and uninjured side for tibiofibular measurements in maximal PF and DF, suggesting anatomic reduction. For Group S, however, there was a significantly larger distance for all three measurements at maximal PF compared to the uninjured ankle (all P < 0 .05). In all but one Group S patient, screws were broken or removed prior to their dynamic CT, allowing possible increased syndesmotic motion, similar to Group T. Despite this, dynamic CT analysis detected increased tibiofibular distance in Group S as ankles moved into maximal PF when compared with the uninjured ankle. Given the importance of anatomic syndesmosis reduction, dynamic ankle CT technology may provide valuable physiologic information warranting further investigation

Malreduction of the syndesmosis is a poor prognosticator following ankle fracture and has been documented in as many as 52% of patients following fracture fixation. The current standard for assessment of reduction of the syndesmosis is bilateral computed tomography (CT) scan of the ankle. Multiple radiographic parameters are utilized to define malreduction, however, there has been limited investigation into the accuracy of these measurements to differentiate malreduction from inherent anatomical asymmetry. The purpose of this study was to identify the prevalence of positive malreduction standards within the syndesmosis of native, uninjured ankles. Bilateral lower extremity CT scans including ankles were screened. Studies were excluded if the patient was skeletally immature, had pathology below the knee or if they had congenital neuromuscular syndromes. The resulting cohort consisted of 207 patients. The indication for bilateral CT scan was femoral acetabular impingement in 110 patients (53%), rotation assessment following arthroplasty in 32 patients (15%), rotation assessment following femoral fracture in 30 patients (14%), rotational assessment for patellar instability in 30 patients (14%) and five miscellaneous indications (2%). Fifty patients were reviewed by three observers independently and to determine inter-observer reliability. A single observer repeated the measurements within the same cohort four weeks later to evaluate intra-observer reliability. Three observers then measured the anterior syndesmotic distance, posterior syndesmotic distance, central syndesmotic distance, fibular rotation and sagittal fibular translation at 1cm from the distal tibial articular surface. Overall side to side variability between the left and right ankle were assessed. Previously studied malreduction standards were evaluated. These included: anterior to posterior syndesmotic distance > 2mm, central syndesmotic difference > 1.5mm, average syndesmotic distance > 2mm, fibular rotational difference > 10o and sagittal translational difference > 2mm. The inter- and intra-observer reliability was good to excellent for anterior, posterior and central syndesmotic distance, and fibular rotation measurements. Sagittal fibular translation had an ICC of 0.583, and thus was only of fair reliability. Side to side comparison revealed statistically significant difference in only anterior syndesmotic difference (p=0.038). A difference of anterior to posterior syndesmotic distance of greater than 2mm was observed in 43 patients (20.2%). Thirty eight patients (17.8%) had a central syndesmotic difference of greater than 1.5mm. A fibular rotational difference of greater than 10o was observed in 49 patients (23%). The average difference between the anterior and posterior syndesmosis was greater than 2mm in 17 patients (8.2%). Nine patients (4.2%) had sagittal translation of greater than 2mm. Eighty one patients (39%) demonstrated at least one parameter beyond previously set standards for malreduction. Only one parameters was anomalous in 54 patients (26%), 18 patients (8%) had two positive parameters, while eight patients (4%) had three. One patient was asymmetrical in all measured parameters. In this study there was no statistically significant asymmetry between ankles. However, 39% of native syndesmoses would be classified as malreduced on CT scan using previously studied malreduction limits. Current radiographic parameters are not sufficient to differentiate mild inherent anatomical asymmetry from malreduction of the syndesmosis

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. 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

Injury to the syndesmosis occurs in 10–13% of all operative ankle fractures and there is evidence that both incomplete treatment and malreduction of the syndesmosis can lead to poor clinical outcomes. Much attention has been given to post–operative malreduction documented by computer tomography (CT), however, there is limited data about the intact positioning and relative motion of the native syndesmosis. The aim of this study is to elucidate more detailed information on the position of the fibula in the syndesmosis during simulated weight–bearing in intact state, with sequential ligament sectioning and following two reconstructive techniques. Fourteen paired, fresh–frozen human cadaveric limbs were mounted in a weight–bearing simulation jig. CT scans were obtained under simulated foot–flat loading (75 N) and in single–legged stance (700 N), in five foot positions: neutral, 15° external rotation, 15° internal rotation, 20° dorsiflexion, and 20° plantarflexion. The elements of the syndesmosis and the deltoid ligament were sequentially sectioned. One limb of each pair was then reconstructed via one of two methods: Achilles autograft and peroneus longus ligamentoplasty. The specimens were rescanned in all 5 foot positions following each ligament resection and reconstruction. Measurements of fibular diastasis, rotation and anterior–posterior translation were performed on the axial cuts of the CT scans, 1 cm proximal to the roof of the plafond. Multiple measurements were made to define the position of the fibula in the incisura. Clinically relevant deformity patterns were produced. The deformity at the incisura was consistent with clinical injury, and the degree of displacement in all ligament states was dependent on the foot position. The most destructive state resulted in the most deformity at the syndesmosis. Differences between the intact and reconstructed states were found with all measurements, especially when the foot was in external rotation and dorsiflexion. There was no significant difference with direct comparison of the reconstructions. This study has detailed the motion of the fibula in the incisura and its variation with foot position. Neither reconstruction was clearly superior and both techniques had difficulty in the externally rotated and dorsiflexed foot positions. This study design can serve as a model for future ex–vivo testing of reconstructive techniques

This study investigated athletes presenting with grade II syndesmosis injuries and identified the clinical and radiological factors important in differentiating a stable from dynamically unstable injury and those findings associated with a longer recovery and return to sport. Sixty-four athletes were prospectively assessed with an average follow-up of 37 months (range 24–66 months). Athletes with an isolated distal syndesmosis (+/− medial deltoid ligament) injury were included. Those athletes with a concomitant ankle fracture were excluded. Those considered stable (grade IIa) were treated conservatively with a boot and progressive rehabilitation. Those with clinical signs of instability underwent arthroscopy and if instability was confirmed (grade IIb) the syndesmosis was stabilized surgically. The clinical assessment of injury to individual ligaments of the ankle and syndesmosis were recorded along with MRI findings, complications and time to return to play. All athletes returned to the same level of professional sport – 28 with IIa injuries returned at a mean of 45 days whereas the 36 with grade IIb injuries returned to play at a mean of 64 days (p< 0.001). Clinical assessment of injury to the ligaments of the syndesmosis correlated well with MRI findings. Those with a positive squeeze test were 9.5 times as likely and those with a deltoid injury 11 times more likely to have an unstable syndesmosis confirmed arthroscopically. The combination of injury to the AITFL and deltoid ligament was associated with a delay in return to sport. Concomitant injury to the ATFL indicated a different mechanism of injury with the syndesmosis less likely to be unstable and was associated with an earlier return to sport. Clinical and MRI findings may differentiate stable from dynamically unstable grade II injuries and identify which athletes may benefit from early arthroscopic assessment and stabilization. It also suggests the timeframe for expected return to play

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

Introduction. Ankle fractures represent approximately 10% of the fracture workload and are projected to increase due to ageing population. We present our 5 years outcome review post-surgical management of ankle fractures in a large UK Trauma unit. Methods. A total of 111 consecutive patients treated for an unstable ankle fracture were entered into a database and prospectively followed up. Baseline patient characteristics, complications, further intervention including additional surgery, functional status were recorded during five-year follow-up. Pre-injury and post-fixation functional outcome measures at 2-years were assessed using Olerud-Molander Ankle Scores (OMAS) and Lower Extremity Functional Scales (LEFS). A p value < 0.05 was considered significant. Results. The mean age was 46 with a male:female ratio of 1:1.1. The distribution of comorbidities was BMI >30 (25%), diabetes (5%), alcohol consumption >20U/week (15%) and smoking (26%). Higher BMI was predictive of worse post-op LEFS score (p = 0.02). Between pre-injury and post fixation functional scores at 2 years, there was a mean reduction of 26.8 (OMAS) and 20.5(LEFS). Using very strict radiological criteria, 31 (28%) had less than anatomical reduction of fracture fragments intra-operatively. This was, however, not predictive of patients' functional outcome in this cohort. Within 5-year period, 22 (20%) patients had removal of metalwork from their ankle, with majority 13 (59%) requiring syndesmotic screw removal. Further interventions included: joint injection (3), deltoid reconstruction (1), arthroscopic debridement (1), superficial sinus excision (2), and conversion to hindfoot nail due to failure of fixation (1). Reduction in OMAS was predictive of patients' ongoing symptoms (p=0.01). Conclusion. There is a significant reduction in functional outcome after ankle fracture fixation and patients should be counselled appropriately. Need for removal of metalwork is higher in patients who require syndesmosis stabilisation with screw(s)

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

Approximately 20% of patients with ankle fracture sustain syndesmosis injury. This is most common in trans-syndesmotic (type B) and supra-syndesmotic (type C) fibula fractures. Intra-operative assessment of syndesmosis integrity is important because failure to treat these injuries can result in ankle instability and pain. Our aim was to audit the documentation of intra-operative testing of syndesmosis during ankle fracture open reduction and internal fixation (ORIF). All patients who had ankle fracture ORIF between 1/1/2010 and 21/11/2011 were included. Pre-operative radiographs were reviewed and fractures were classified according to AO classification. Operation notes were reviewed for documentation of assessment of syndesmosis integrity. 153 patients, of mean age 50 years (15–93) were included. 60% (n=92) were female. In 78% of cases (n=119), an assessment of syndesmosis integrity was documented in the operation note. Of the patients with no documented syndesmosis assessment (n=35), the majority had type B fractures (n=34). One patient had a type C fracture. We have shown that 22% of patients undergoing ankle ORIF for fracture do not have documented assessment of syndesmosis integrity. We suggest that all patients who have ankle ORIF should have intra-operative assessment and documentation of syndesmosis integrity so these injuries are identified and treated accordingly