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Background: The lateral fibular stress test (LFST), also known as the hook or Cotton test, is commonly performed to assess syndesmotic instability intraoperatively. Several studies have used 100 N as the force applied when performing the LFST to detect syndesmotic instability, though no evidence-based requisite force has been described for the test. We hypothesize that surgeons do not apply force uniformly or consistently when performing the LFST and that substantial variation exists. Fundamentally, this could lead to inconsistent diagnosis of syndesmotic instability as surgeons may not be applying the force in a consistent manner. Methods: A biomechanical ankle model consisting of an industrial force gauge attached through a SawBones model was fashioned. Orthopaedic attending surgeons and trainees were asked to perform a series of LFSTs and to simulate the force they typically apply intraoperatively. Basic demographic data were collected on each participant. Results: Thirty-three surgeons participated in the study, including 18 trainees. The median (IQR) force applied during the LFST was 96.42 (71.42-126.33), 87.49 (69.19-117.40), 99.99 (79.91-137.49), for the pooled group, attendings, and trainees respectively. More than half (54.5%) of all trials were less than 100 N (57.8% of surgeons, 51.8% trainees). Intraobserver correlation was excellent within the overall cohort (0.92, P < .001), trainees (0.90, P < .001), and attendings (0.94, P < .001), respectively. Interobserver reliability was fair among the overall cohort (κ =0.28, P = .49), and poor between the attendings (κ = 0.11, P = .69) and the trainees (κ = 0.05, P = .82), respectively. Conclusion: Our study demonstrates that the amount of force applied by typical surgeons when performing the LFST test is highly variable. Variable force application when performing the LFST may lead to inconsistent detection of syndesmotic instability, which may portend a poorer outcome. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: The quest for optimal treatment of acute distal tibiofibular syndesmotic disruptions is still in full progress. Using suture-button repair devices is one of the dynamic stabilization options, however, they may not be always appropriate for stabilization of length-unstable syndesmotic injuries. Recently, a novel screw-suture repair system was developed to address such issues. The aim of this study was to investigate its performance in comparison to a suture-button stabilization of unstable syndesmotic injuries. Methods: Eight pairs of human cadaveric lower legs were CT scanned under 700 N single-leg axial loading in five foot positions - neutral, 15° external/internal rotation and 20° dorsi-/plantarflexion - in 3 different states: (1) pre-injured (intact); (2) injured, characterized by complete syndesmosis and deltoid ligaments cuts simulating pronation-eversion injury types III and IV as well as supination-eversion injury type IV according to Lauge-Hansen; (3) reconstructed, using a screw-suture (FIBULINK, Group 1) or a suture-button (TightRope, Group 2) implants for syndesmotic stabilization, placed 20 mm proximal to the tibia plafond/joint surface. Following, all specimens were: (1) biomechanically tested over 5000 cycles under combined 1400 N axial and +-15° torsional loading; (2) rescanned. Clear space (diastasis), anterior tibiofibular distance, talar dome angle and fibular shortening were measured radiologically from CT scans. Anteroposterior, axial, mediolateral and torsional movements at the distal tibiofibular joint level were evaluated biomechanically via motion tracking. Results: In each group clear space increased significantly after injury (p <= 0.004) and became significantly smaller in reconstructed compared with both pre-injured and injured states (p <= 0.041). In addition, after reconstruction it was significantly smaller in Group 1 compared to Group 2 (p < 0.001). Anteroposterior (AP) and axial movements were significantly smaller in Group 1 compared with Group 2 (p < 0.001, Figure). No further significant differences were identified/detected between the groups (p >= 0.113). Conclusion: Although both implant systems demonstrate ability for stabilization of unstable syndesmotic injuries, the screwsuture reconstruction provides better anteroposterior translation and axial stability of the tibiofibular joint and maintains it over time under dynamic loading. Therefore, it could be considered as a valid option for treatment of syndesmotic disruptions. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Foot and ankle injuries account for a large percentage of the over one million injuries sustained by high school level athletes. To date, many studies have examined the epidemiology of lower extremity injuries and ankle sprains, but few studies have classified sprains into subtypes across multiple sports. The purpose of this study was to describe the epidemiology of ankle sprain subtypes across 9 common high school sports. Methods: Athlete exposure and injury specific data from 7 seasons (2014 to 2021) were collected using the internet-based High School Reporting Information Online (High School RIO), a national high school sports injury surveillance system, for athletes participating in 1 of 9 sports (boys' and girls' soccer, girls' volleyball, boys' and girls' basketball, boys' baseball, girls' softball, boys' football, boys' wrestling). Incidence and ligament involvement of foot and ankle injuries were examined, with incidence being calculated as 1 injury per 10,000 athlete exposures (AE). Results: Ankle ligament injuries accounted for 89.0% of the 7,321 foot and ankle injuries across the 9 sports (81-94%). Girls and boys' basketball had the highest incidence of sprains, 3.46 and 3.37 respectively. Ankle ligament injuries accounted for 35.9% of all lower extremity injuries in basketball players. 85.0% of the sprains were classified as lateral ligament, 4.0% medial ligament, 11.5% syndesmosis (8.6% partial and 2.9% complete syndesmosis injuries). Football had the highest percentage of syndesmosis injuries at 11.0%, and the highest incidence of both syndesmosis injuries (0.44) and medial ligament injuries (0.17). Surgical intervention was required in 4.3% of complete syndesmosis injuries and 0.7% of lateral ligament injuries. No differences were found in incidence of ankle ligament injuries comparing pre-COVID-19 seasons (2014-2020) to the 2020-2021 season. Conclusion: Ankle sprains account for a large percentage of foot and ankle injuries sustained by high school level athletes. Syndesmosis injuries occur more commonly in football and are 6 times more likely to require early surgical intervention compared to lateral ligament injuries. Identifying sports commonly involved in these injuries and classifying the sprains is the first step in implementing early identification, rehabilitation, and prevention programs. Future studies should examine the efficacy of injury prevention programs and rates of ankle sprains among high school level athletes. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Forced external rotation is hypothesized as the key mechanism of syndesmotic ankle injuries, inducing a three-dimensional deviation from the normal distal tibiofibular joint alignment. These lesions, especially when subtle, present a deceitful diagnostic challenge. Current diagnostic imaging modalities are impeded by a two-dimensional assessment, without considering ligamentous stabilizers. Accurate diagnosis of syndesmotic lesions should involve 3D weightbearing osseous imaging in combination with - preferably automated- inclusion of patient-specific ligamentous information. Therefore, our aim is two-fold: (1) to construct a three-dimensional articulated statistical shape model of the normal distal tibiofibular joint with inclusion of ligamentous morphometry and (2) to detect differences in predicted syndesmotic ligament length of patients with syndesmotic lesions with respect to normative data. Methods: Training data comprised non-weightbearing CT scans from asymptomatic controls (N= 76, Mean age 63 +/- 19 years), weightbearing CT scans from patients with syndesmotic ankle injury (N = 13, Mean Age 35 +/- 15 years) and their weightbearing healthy contralateral side (N = 13). CT scan segmentation was used to generate 3D bone models in the control and patient group. All ankles were aligned based on the tibia. Path and length of the syndesmotic ligaments were predicted using a discrete element model, wrapped around bony contours. Statistical shape model evaluation was based on accuracy, generalization and compactness. The predicted ligament length in patients with syndesmotic lesions was compared to healthy controls by use of two-tailed TwoSample student's t-test. Results: Our presented skeletal shape model described the training data with an accuracy of 0.23 +/- 0.028 mm. Mean prediction accuracy of ligament insertions was 0.53 +/- 0.12 mm. Mean length of the Anterior inferior tibiofibular ligament was 12.26 +- 1.89mm for the control cases, 12.32 +- 1.58 mm for the contralateral cases and 14.13 +- 1.48 mm for the cases with syndesmotic lesions. Statistically significant differences were found between the latter two (95% CI [ 0.323.29], p = 0.017) There was a significant correlation between presence of syndesmotic injury and the positional alignment between the distal tibia and fibula (r = 0.873, p < 0,001). Conclusion: Statistical shape modelling combined with patient-specific ligament wrapping techniques can facilitate the diagnostic workup of syndesmotic ankle lesions under weightbearing conditions. In doing so, an increased anterior tibiofibular distance was detected, corresponding to an 'anterior open-book injury' of the ankle syndesmosis as a result of anterior inferior tibiofibular ligament elongation/rupture (Figure 1). [ABSTRACT FROM AUTHOR]

Introduction/Purpose: High ankle sprains or syndesmotic lesions can occur after an external rotation force in a dorsiflexed foot. These lesions may present isolated or combined with medial collateral ligaments lesions or fractures. Unstable lesions should be operatively treated since syndesmotic instability can cause pain, disability, chondral lesions and arthritis. A recent biomechanical cadaveric study suggested that syndesmosis suture button fixation with suture tape augmentation can restore stability to a pre injury level, while suture button alone was insufficient to restore stability and screw fixation was associated with overtightening of the syndesmosis. The purpose of this work is to describe a new minimally invasive arthroscopic technique that uses a synthetic tape to augment suture button fixation of syndesmotic instability. Methods: After arthroscopic debridement of the syndesmosis, one bone tunnel is made with a 4.0mm drill at the anterolateral distal tibia rim and at the anterior distal fibula just above the anterior talofibular ligament origin. A 4,75mm swivelock armed with a fibertape (Arthrex©) is introduced at the distal fibula hole. After obtaining adequate syndesmotic reduction with the help of a reduction clamp, suture button fixation was made through a mini lateral access. The fibertape was then appropriately tensioned and inserted at the distal tibia hole with another 4,75mm swivelock. Adequate reduction was observed with the Mercedes-Benz sign and stability was confirmed arthroscopically. Results: Only a few patients were submitted to this technique. At short follow up, none of them presented with complications or complaints Conclusion: We believe that unstable syndesmotic treatment using the suture button fixation and anterior inferior tibiofibular arthroscopic augmentation with suture-tape described in this work can restore syndesmotic stability to pre injury levels with low morbidity and lesser complication rates compared to other techniques. Nonetheless, comparative clinical studies are still needed to confirm our hypothesis. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: The lateral fibular stress test (LFST), also known as the hook or Cotton test, is commonly performed to assess syndesmotic instability intraoperatively. Several studies have determined that 100 Newtons (N) is the required force applied when performing the LFST to detect syndesmotic instability. We hypothesize that surgeons do not uniformly nor consistently apply 100N of force when performing the LFST and that substantial variation exists. Fundamentally, this could lead to under-detection of syndesmotic instability as surgeons may not be applying the requisite force in a consistent manner. Methods: A biomechanical SawBones lower leg model including simulated soft tissue envelope (SawBones inc., Vashon Island, Washington) was mounted to a board and a 1cm diameter hole was drilled across the tibia and fibula in the area of the syndesmosis. An industrial force gauge (Nidec-Shimpo, Kyoto, Japan) was then mounted. A metal extension piece was passed from the force gauge through the hole and positioned so that the tip was exposed on the lateral side of the model. A commonly utilized reduction clamp was affixed to the force gauge. Orthopaedic attending surgeons and trainees were asked to perform a series of LFSTs and to simulate the force they typically apply intra-operatively and this force was recorded in Newtons (N). Basic demographic data was collected on each participant. Results: 33 surgeons participated in the study, including 18 trainees. The median (IQR) force applied during the LFST was 96.42(71.42-126.33), 87.49 (69.19-117.40), 99.99(79.91-137.49), for the pooled group, attendings, and trainees respectively. Over half (54.5%) of all trials were less than 100N (57.8% of surgeons, 51.8% trainees). The distribution of pulls is shown in Figure 1. Intraobserver correlation was excellent within the overall cohort (0.92, p<0.001), trainees (0.90, p<0.001) and attendings (0.94, p<0.001), respectively. Inter-observer reliability was fair among the overall cohort (Kappa =0.28, p=0.49), and poor between the attendings (Kappa=0.11, p=0.69), and the trainees (Kappa=0.05, p=0.82), respectively. Conclusion: Our study demonstrates that the amount of lateral force applied by surgeons in a biomechanical ankle model when performing the LFST is variable and often less than 100N. Inadequate force application when performing the LFST may lead to under-detection of syndesmotic instability which may portend a poorer outcome. Either the intraoperative use of force gauges and/or specific practice outside of the operating theatre (to become familiarized with the proprioceptive feel of generating the requisite force) may permit surgeons to consistently apply the test in a manner that is clinically reproducible. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Despite the success of surgical intervention, about 13-35% of patients continue to have ankle symptoms after surgery for lateral ankle instability which could be due to presence of undetected and thus untreated injury to other ankle ligaments.Concomitant lateral ankle ligament and syndesmotic ligamentous injuries are common. It is unknown, however, whether syndesmotic ligaments directly contribute to lateral ankle stability. Therefore, the aim of this study was to fluoroscopically evaluate whether the syndesmotic ligaments contributes to lateral ankle stability. Methods: Twenty-four above-knee cadaveric specimens were divided into three groups that underwent fluoroscopic evaluation for lateral ankle stability. In all the groups, the assessment was first done with all syndesmotic and ankle ligaments intact. Thereafter, Group 1 underwent sequential transection of the lateral ankle ligaments: (1) anterior talofibular ligament (ATFL), (2)calcaneofibular ligament(CFL), and (3)posterior talofibular ligament (PTFL). Group 2 underwent sequential transection of the lateral ankle ligaments followed by the syndesmotic ligaments: (1) ATFL, (2) CFL, (3) PTFL, (4) anterior inferior tibiofibular ligament(AITFL), (5)interosseous ligament(IOL), and (6)posterior inferior tibiofibular ligament (PITFL). Group 3 alternating and sequential transection of the syndesmotic and lateral ankle ligaments: (1) AITFL, (2) ATFL, (3) CFL, (4) IOL, (5) PTFL, and (6) PITFL. In all scenarios, three loading conditions were considered:(1)An anterior drawer test at 50N and 80N of direct force, (2) talar tilt under 1.7Nm torque, and (2) lateral clear space (LCS) under 1.7Nm torque. Wilcoxon rank-sum test was used to compare the findings of each ligamentous transection state to the intact state. Results: The lateral ankle remained stable after transection of all syndesmotic ligaments (AITFL, IOL, PITFL). However, after additional transection of the ATFL, the lateral ankle became unstable in varus and anterior drawer testing conditions (p-values ranging from 0.036-0.012). Lateral ankle instability was also observed after transection of the ATFL and AITFL (p-values ranging from 0.036-0.012). Subsequent transection of the CFL worsened the lateral ankle instability. Conclusion: Our findings suggest that syndesmotic injuries can destabilize otherwise stable lateral ankle sprains. When treating lateral ankle instability, clinician should maintain a lower threshold for operative intervention for syndesmotic stabilization if there are any residual symptoms over the AITFL. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Portable fluoroscopy devices provide point-of-care imaging in emergency and out-patient clinics. In patients suffering from ankle syndesmosis injuries, imaging under physiologic load can lead to more accurate diagnosis, particularly in subtle cases. In this study, we compared weightbearing images obtained using a novel lightweight portable battery-powered fluoroscopy device with a conventional radiography device regarding syndesmosis examination measurements. Methods: In this prospective study, eleven healthy participants underwent bilateral three-view weightbearing imaging of both ankles using a radiography (X-ray group) device and a portable fluoroscopy system (Smart-C group). Radiographic measurements were done by two observers on anteroposterior, mortise, and lateral views were compared between the two techniques. These measurements included talar tilt, tibiofibular clear space, tibiofibular overlap, plafond malleolar angle, medial distal tibial angle, medial clear space, lateral distal tibial angle, anterior and posterior tibiofibular distance were measured using the appropriate view. Data were compared between the two techniques; the interobserver agreement was calculated within each group. P<0.05 was considered statistically significant. Results: Comparing the two imaging modalities, there was no significant difference between the measurements in Smart-C and Xray groups except plafond malleolar angle. The overall interobserver agreement was excellent between the two observers. There was no significant difference between the measures by the two observers and between the bilateral ankles. Conclusion: Our results support the use of weightbearing images using portable fluoroscopy device as an alternative for the conventional radiography systems, particularly in limited-resource settings. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Malreduction in ankle syndesmosis repair is associated with post-operative pain, instability, and revision. Although multiple surgical techniques are designed to minimize malreduction, little is understood regarding the multi-factorial sources of error these techniques aim to address. For example, image interpretation errors may be particularly problematic, as previous work indicates identifying subtle fibular displacements from imaging is challenging for experienced orthopaedic trauma surgeons. In this context, this study evaluates whether surgical experience and/or inclusion of a visual aid improves surgeon accuracy during an image interpretation task. The task originates from the center-center technique, which is designed to minimize syndesmosis malreduction by drilling through the aligned centers of the tibia and fibula on an internally-rotated, lateral ankle x-ray. Methods: Twenty-eight individuals participated in this IRB-approved study (10 orthopaedic surgery attendings, 8 orthopaedic surgery residents, 10 medical students). Each evaluated 90 lateral ankle images arranged in two equal sets. In each set, the fibula was displaced from perfectly centered (-40% posterior to +40% anterior in 10% increments; each increment repeated 5 times). The two sets were identical, except one was augmented with a visual aid (or crosshair) marking the center of the tibia. Image and set order were randomized to control for learning effects. For each image, participants classified the fibula as 'centered' or 'noncentered' while wearing eye-tracking glasses. The glasses recorded two physiological measures of cognitive burden: blinks per image and image interpretation time. Statistical analyses tested the hypotheses that surgical experience and addition of a visual aid improved interpretation accuracy and decreased cognitive burden. Statistical significance (p <= 0.05) was evaluated using ANOVA followed by paired t-tests. Results: All participants accurately identified images with large fibular displacements (>20%) and perfectly centered (0%) images; however, interpretation accuracy at small displacements (10%) approximated random chance (Fig. 1A). Inclusion of a visual aid significantly improved image interpretation accuracy for both the full image set (p = 0.015, Fig. 1B) and images with small displacements (p = 0.025, Fig. 1A 10% and 20%). Although surgical experience was not a significant predictor of interpretation accuracy, surgical experience did significantly influence physiological measures of cognitive burden. Interestingly, inclusion of a visual aid slightly increased cognitive burden as measured by blinks per image for trainees, but significantly decreased this metric for attendings (p = 0.014, Fig. 1C). Compared to attendings, time per image was significantly increased for residents (p = 0.007), but not medical students (Fig. 1D). Conclusion: This study demonstrates that a visual aid can improve image interpretation accuracy for both experienced surgeons and trainees. Interestingly, the inclusion of the visual aid decreased the physiologically measured cognitive burden of attendings, but not trainees. This suggests that additional visual information displayed on an x-ray image may be processed and used differently by experienced versus inexperienced surgeons. Thus, this study provides foundational evidence that augmenting images can improve surgical accuracy and motivates future work to characterize how image augmentation influences clinical and educational outcomes. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Maisonneuve fractures consist of a fracture of the fibula in the proximal third with associated syndesmotic injury. Surgical management generally involves restoration of fibula length, reduction of the syndesmosis, and stabilization of the syndesmosis. Flexible fixation devices have gained popularity for syndesmotic fixation over the last several years. Current flexible fixation devices are not reliable for fixation of length unstable patterns of injury, like the Maisonneuve fracture. The purpose of the study was to evaluate the results of a new screw- suture syndesmotic device providing aperture fixation of the syndesmosis for fixation of Maisonneuve fractures. Methods: 10 consecutive patients with Maisonneuve injuries were treated with indirect restoration of fibula length, open reduction of the syndesmosis, and stabilization of the syndesmosis with the screw suture device. Talocrural angle and medial clear space was measured and recorded at time of injury, post operatively and 6 months. Rate of hardware removal was recorded.***2 patients are 2 months short of 6 months. both have healed their proximal fibula fractures so no changes to data are anticipated *** Results: There were 5 males and 5 females. 5 patients slipped on ice, 4 patients fell on uneven walking surfaces, 1 patient was in a motorcycle accident. 2 patients had associated posterior malleolus fractures, 1 was fixed with a posterior plate. 1 patient had a medial malleolus fracture repaired with 2 screws. 9 devices were placed independently. 1 device was inserted through a 4 hole 1/3 tubular plate. Average time to surgery was 12.3 days (range 5-24 days). Talocrural angles averaged 8.92 (4.8-14.5mm) on injury films, 13.8mm (10.6-17mm) post operatively and 13.5mm (10.6-16.6) at 6 months. Medial clear space measurement averaged 5.68mm (2-10mm) on injury films, 2.06mm (1.9-2.3mm) post operatively and 2.1mm (2-2.3mm) at 6 months. No devices required removal during the study period. Conclusion: The screw-suture device provided length stable fixation for treatment of Maisonneuve fracture patterns. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Introduction: The diagnosis of low-energy syndesmotic injuries continues to be a challenge, and there is no standard for it. Being the dynamic exams, the ones with the best performance. With the development of Weight-Bearing computerized tomography (WBCT), the understanding of their lesion patterns has improved, however, there is high variability in the syndesmotic anatomy between different individuals, with asymmetry parameters in up to 89% of healthy syndesmosis. therefore the best element to evaluate them is the healthy contralateral ankle and compare these parameters. However, what are the normal values in our population, or the possible anatomical differences according to different age groups, in the morphology of the syndesmal notch of our patients, nor that there is a real symmetry between both ankles. Methods: Retrospective analysis of comparative bilateral ankle WBCT in healthy patients from March 2018 to July 2021 according to the parameters: anterior, posterior and central syndesmal distance, fibular rotation, sagittal translation and area. All patients with comparative bilateral ankle weight-bearing CT taken since January 2018 to August 2021, patients without history of ankle injuries, were included in the analysis. That have required a comparative bilateral WBCT to study another pathology. Patients with a history of acute or chronic ankle or syndesmal injuries, patients with degenerative ankle joint injuries, with severe misalignments > 10° in varus or valgus, incomplete or non-comparative study were excluded. Results: 150 patients with comparative bilateral WBCT were evaluated. Among the ankles evaluated with WB CT in a comparative manner, it is established that there were no significant differences between both ankles of subjects with healthy ankles (Wilcoxon Test) in anterior syndesmal distance (SD), posterior SD, central SD, syndesmal area (p > 0.05). While fibular rotation and sagittal translation showed significant differences between the measurements in healthy ankles, evaluated with comparative bilateral WB CT in independent evaluations (p < 0.05). Regarding the differences by age range established for the different syndesmotic reduction parameters, for the different subgroups of patients under 40 years of age, 40 and 60 years of age and over 60 years of age, no significant differences were generated between them (Wilcoxon test). Conclusion: We have established normal ranges for measurements in the syndesmal anatomy in axial slices during weight bearing CT, as well as that there are no differences between the right and left ankle in healthy ankles in anterior, posterior and central syndesmal distance, or syndesmal area. Being these parameters, the most suitable as internal control for patients with suspected syndesmotic injury regardless of the age of the patients. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: The interosseous ligament (IOL) of the ankle, together with the anterior and posterior inferior tibiofibular ligament (ATFL and PITFL), are important structures which stabilizes the inferior tibiofibular joint. Besides securing the fibula tightly to tibia, these ligaments prevent excessive lateral fibular displacement and external talar rotation. Thus, any injury to either bone or ligaments at this level will result in instability and abnormal joint motion. Our study aims to evaluate the anatomical angle of the ankle interosseous ligament on magnetic resonance imaging (MRI) studies to better understand the biomechanical forces that act within the distal tibiofibular joint, relevance of assimilating the anatomical angle and its relevance in syndesmosis fixations. Methods: MRIs of ankles were chosen anonymously from the global PACS system database between the months September to October 2020. A total of 34 patients' MRIs were identified. Patients who sustained bone or soft tissue injury at the level of ankle syndesmosis were excluded to avoid any ambiguity in altered position of the IOL due to trauma. The angle of interosseous ligament from the tibial plafond was measured on the coronal plane. The axial plane was used as a reference to ensure correct position of measurement. This was done in collaboration with radiologists to ensure that IOL is correctly identified, prior to start of the study. The angle was measured separately by two different investigators and the average angle was obtained for each MRI. Data was tabulated and statistical analysis was done. Results: All of the 20 ankles identified during the study period were included in the analysis. There were 10 male and 10 female patients. Nine were left ankles and 11 were right ankles. The median age was 54 years (range 14 - 83). The mean IOL angle was 65.66 degrees. The standard error of difference between the 2 investigators was 0.567 and the two-tailed P value was 0.4980. By conventional criteria, this difference is considered to be not statistically significant. Conclusion: The ligament angle formed against tibial plafond bears theoretical relevance. We propose further cadaveric studies to confirm IOL anatomical ligament angle and carrying out implant failure stress test in a lab between the implant inserted parallel to the normal angle of IOL (65 degrees) vs 90 degrees. We also propose that such studies may show that all implants to stabilize the syndesmosis may be more effective if we try to reproduce nature by replicating as close to the IOL's anatomical angle rather than using a long held dogma of fixing syndesmosis to neutralize the forces as nature intended [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Tibiofibular syndesmotic injuries occur in association with fractures or in isolation, often referred to as 'high ankle sprains'. Dynamic instability of the syndesmosis in the high-level athlete is difficult to diagnose, requiring a high index of suspicion for the identification and surgical stabilization to prevent late adverse sequelae, such as recurrent ankle pain, anterolateral soft tissue impingement, local synovitis, and chronic instability of distal syndesmosis. Both CT and MRI have been helpful in identifying syndesmotic injuries, but are static, non-weight bearing imaging modalities that cannot demonstrate dynamic instability, which may miss the unstable nature of some injuries. We present a novel imaging technique utilizing weight-bearing CT with syndesmotic stress in which a case is presented to illustrate it's utility in the elite athlete. Methods: Cone beam weight bearing computed tomography (WBCT) is a well-described imaging modality for evaluation of foot and ankle injuries. We have found it highly beneficial to teach our CT technologists about syndesmosis injuries and the importance of augmented physiologic stress applied across the ankle joint (in addition to the standard WBCT) to better demonstrate instability or motion, particularly at the tibiofibular syndesmosis. To perform an augmented stress weight bearing CT, the patient is positioned in the WBCT scanner and initial images are acquired in the standing weight bearing position with feet directed forward and weight distributed equally. A second image acquisition is then performed (augmented stress), where the patient is coached to firmly plant both feet on the ground and internally rotate the shin and knee. This places an external rotational moment on the TFS due to the planted foot and ankle. Results: Our case is of a 21-year-old male collegiate football player, wide receiver, that sustained an eversion injury to his left ankle during game play. He subsequently was unable to bear weight, with pain anteriorly over the distal tibiofibular joint. Pain was reproduced with dorsiflexion and eversion stress; however, he had a negative 'squeeze test' on examination. Initial weight bearing radiographs were negative. An MRI was obtained which did not reveal evidence of syndesmotic injury. Subsequently, weightbearing CT stress examination of the syndesmosis was obtained and found to have 8 mm widening of the tibiofibular syndesmosis, 4 mm increased when compared to his contralateral, uninjured, ankle. This was also compared with a neutral WBCT without stress that did not illustrate the unstable nature of the injury. The coronal images also demonstrate increased uncovering of the talus underneath the tibial plafond. Conclusion: Tibiofibular syndesmotic injuries have historically been detected with standard x-ray, stress plain films, standard CT, and MRI. In cases where injury and stability are not obvious by these diagnostic studies, more subtle injuries may be frequently missed leading to increased morbidity, chronic instability, and increased return to play times. The addition of a stress view on weight-bearing CT can allow further identification of instability of the syndesmosis. We propose this technique for diagnosing otherwise unrecognized, subtle dynamically unstable syndesmosis injuries where clinical suspicion persists despite negative imaging, particularly in the elite athlete. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Portable ultrasonography (P-US) is increasingly used to diagnose syndesmotic instability. The aim of this study was to evaluate syndesmotic instability by measuring the distal tibiofibular clear space (TFCS) in a cadaveric model using PUS with progressive stages of syndesmotic ligamentous transection. Methods: Ten fresh lower leg cadaveric specimens amputated above the proximal tibiofibular joint were used. Using P-US, the TFCS was evaluated in the intact stage and after progressive sectioning of the 1) anterior-inferior tibiofibular ligament (AITFL), 2) interosseous ligament (IOL), and 3) posterior-inferior tibiofibular ligament (PITFL). The TFCS was measured in both the unstressed (0 Nm) state and with 4.5 Nm, 6.0 Nm, 7.5 Nm, and 9.0 Nm of external rotation stress at each stage of ligamentous transection stage using both P-US and fluoroscopy. Results: When assessed with P-US, partial syndesmotic injury encompassing the AITFL and IOL resulted in significant TFCS widening at 4.5 Nm of external rotation torque when compared to intact state with a TFCS-opening of 2.6 +- 2 mm, p = 0.01. In contrast, no significant differences in TFCS were detected using fluoroscopy. Only a moderate correlation was found between PUS and fluoroscopy. Conclusion: P-US is much more sensitive than fluoroscopy in diagnosing syndesmotic instability during external rotation stress examination. Extrapolated to the clinical setting, 4.5 Nm of force can be used when comparing to the stressed, uninjured side, and may be better tolerated by patients than higher torque values. When using P-US, a TFCS-opening of 2.6 mm is likely to correlate with syndesmotic instability. While absolute threshold values may vary between individuals, the ready availability of the contralateral, uninjured side overcomes this constraint. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: When treating ankle fractures, the presence of talar osteochondral lesions and the extent of ligamentous injury are associated with the severity of injury. The Danis-Weber classification system has been used to predict potential ligament damage. The purpose of this study is to validate the ligament injury patterns that have been proposed to occur with the Danis-Weber Classification and identify the cartilage injury pattern that occurs on the talus with each fracture type. Methods: A prospective, multi-center foot and ankle arthroscopy registry was queried for patients who underwent arthroscopic treatment of ankle fractures. Preoperative and intraoperative findings were noted, including the Danis-Weber fracture classification, presence and location of osteochondral damage, and unstable deltoid, and/or syndesmotic ligaments. Kendall's tau-b, a nonparametric correlation coefficient for ordinal variables, was used to measure the strength and direction of association between Weber fracture type and the presence of a syndesmotic injury, deltoid ligament tear, medial malleolus fracture, or osteochondral lesion. The locations of osteochondral damage were compared as percentages. Results: 73 subjects were prospectively collected as part of a multicenter ankle arthroscopy database. Average subject age was 43 years (SD = 17) with 59% female and 41% male. A significant association between the presence of a syndesmotic injury and fracture type was identified, with syndesmotic injuries more likely occurring with a Weber C fracture (p < 0.0005). A significant association was not identified between Weber classification and a deltoid tear or medial malleolus fracture (p = 0.47, p = 0.79). Location of the talar osteochondral lesions were as follows: 22% medial-anterior, 22% lateral-anterior, 22% lateral-central, 17% central-anterior, 9% medial-central, 4% later-posterior, 4% central. There was no significant association identified between Weber classification and the location of the osteochondral injury (p = 0.99). Conclusion: Concurrent injuries with syndesmotic disruption, deltoid ligament tears, medial malleolus fractures, and osteochondral lesions have been proposed to be associated with Weber C ankle fractures. However, in this multicenter study, only syndesmotic injuries were associated with the Weber C classification. This study found similar rates of medial malleolus fractures and osteochondral lesions in Weber B and C type fractures. [ABSTRACT FROM AUTHOR]