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Category: Ankle; Arthroscopy Introduction/Purpose: Syndesmotic instability, when subtle, can be challenging to diagnose-and often requires visualization of the syndesmosis during applied stress. Portable ultrasonography is increasingly used to evaluate ankle instability at the point of care. This study aims to evaluate 1) whether portable ultrasonography (P-US) can diagnose syndesmotic instability in the sagittal plane, and 2) how P-US measurements compare to arthroscopic evaluation. Methods: Eight fresh, above-knee cadaveric specimen were used. The syndesmosis was evaluated with P-US and arthroscopy in the intact state, and thereafter with progressive sectioning of, 1) anterior-inferior tibiofibular ligament (AITFL), 2) interosseous ligament (IOL), and 3) posterior-inferior tibiofibular ligament (PITFL). Sagittal plane translation was simulated with 100N of anterior to posterior (A to P) and posterior to anterior (P to A) directed force using a bone hook. Separately, a 50N manual force was applied to the fibular tip and measured with P-US to simulate a fibular 'shuck test' performed in the clinical setting. Results: When all three syndesmotic ligaments were transected, there was a significant increase in fibular motion in the sagittal plane when evaluated using portable ultrasonography with application of 50N of manual pressure and when applying a 100N hook test when measuring total sagittal plane motion (p=

Category: Ankle 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 P- US 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 P- US 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.

Category: Ankle; Sports; Trauma Introduction/Purpose: While the lateral hook test (LHT) has been widely used to arthroscopically evaluate syndesmotic instability in the coronal plane, it is unclear whether the angulation of the applied force has any impact on the degree of instability. The aim of this study was to determine if changing the direction of the force applied while performing the LHT impacts the amount of coronal diastasis observed in purely ligamentous syndesmotic injuries. Methods: In 10 cadaveric specimens, arthroscopic evaluation of the distal tibiofibular joint in the coronal plane was performed. Anterior and posterior third coronal plane diastasis were assessed in the intact state and repeated after sequential transection of the, 1) anterior inferior tibiofibular ligament (AITFL), 2) the interosseous ligament (IOL) and the 3) posterior inferior tibiofibular ligament (PITFL). In all scenarios, the lateral hook test (LHT) was performed under 100N of laterally directed force. Additionally, LHT was also performed under 1) anterior inclination of 15 degrees and 2) posterior inclination of 15 degrees in the intact and AITFL+IOL deficient state. One-way ANOVA with post hoc Tukey HSD was used to test for significant differences in coronal plane measurements between each stage of ligament transection, and to determine the effect of different directions of force application on coronal space measurements in the intact and AITFL+IOL transected states. Results: Compared to the intact state, the distal tibiofibular joint remained stable after transection of AITFL under laterally directed force with no angulation. However, after additional transection of the IOL, the syndesmosis became unstable in the coronal plane (p = 0.029 and 0.025 for anterior and posterior third diastasis, respectively). This instability worsened further with subsequent transection of the PITFL (p =

Category: Ankle; Trauma Introduction/Purpose: Despite the fact that stress fluoroscopy is the most common method of quantifying lateral ankle instability, ultrasound evaluation has grown in popularity as a way to assess ankle stability at the point of care due to its simplicity, accuracy, low cost, and lack of exposure. The aim of this study is to introduce a new method for evaluating lateral ankle instability using ultrasound. Methods: A 37-year-old man with history of lateral ankle ligament injury underwent ultrasound and fluoroscopic evaluation. The anterior drawer distance (ADD) was quantified under anterior drawer stress. During ADD measurement, the patient sat with the knee extended and the heel on the examination table or chair, and the examiner performed the anterior drawer test (Image 1a). The amount of talar movement was measured as an ADD using an ultrasound probe placed on the posteromedial side of the ankle (Image 1b). A lateral clear space (LCS) was also measured under varus stress using ultrasound from the tip of the lateral malleolar to the lateral process of the talus. The aforementioned measurements were repeated under stress fluoroscopy and compared with ultrasound findings. Results: On ultrasound evaluation, the ADD was 7.1 mm and the LCS was 17.1 mm. Furthermore, the stress fluoroscopic evaluation yielded a similar result, with an ADD of 8.7 mm and an LCS of 17.5 mm. Conclusion: Our findings suggest that this new method of evaluation of lateral ankle instability under dynamic ultrasound appears to be a highly accurate and useful alternative for assessing lateral ankle stability at the point of care in a radiation-free, non- invasive, and low-cost manner.

Category: Ankle; Arthroscopy; Basic Sciences/Biologics Introduction/Purpose: The lateral hook test is considered the gold standard for the diagnosis of coronal plane syndesmotic instability during arthroscopy. The amount of distal tibiofibular space is directly related to the amount of lateral directed applied force. This study aims to determine the optimal amount of forced needed during a lateral hook test to evaluate syndesmotic instability in the coronal plane. The secondary aim was to determine the amount of displacement variation that occurs when the lateral force is angled anteriorly or posteriorly. Methods: Ten fresh-frozen above-knee amputated cadaveric specimens underwent arthroscopic evaluation of the distal tibiofibular joint. The assessment was done first with all syndesmotic and ankle ligaments intact and subsequently with transection of the anterior inferior tibiofibular ligament (AITFL) and the interosseous ligament (IOL). In all scenarios, a lateral hook test was performed under increasing force from 0N to 120N of direct force, with increments of 20N. The lateral hook test was performed in: 1) the neutral position (no angulation), 2) anterior inclination of 15 degrees, and 3) posterior inclination of 15 degrees under the aforementioned force. Anterior and posterior coronal plane distal tibiofibular space were arthroscopically measured. Descriptive statistics were employed to determine the force and the most sensitive method to pull during arthroscopic evaluation to detect syndesmotic instability. Results: Among the specimens, after transection of AITFL and IOL, the anterior and posterior coronal plane space increased with increment in force until 60N and then displayed no change in these measurements despite the increase in force. In the intact state, there was an increase in syndesmosis coronal space with increase in force. Of the three methods of force application, the posteriorly directed force has the largest absolute value for the anterior and posterior coronal space, suggesting it is the most sensitive in distinguishing between stable and unstable syndesmotic injury. Conclusion: Arthroscopic coronal plane evaluation under 60N of direct force is best suited to distinguish stable from an unstable syndesmosis. Syndesmosis anterior and posterior coronal plane space measurement demonstrate the largest absolute difference when subjected to posteriorly directed force, suggesting that this new method of assessment has the highest potential for diagnosing even subtle syndesmotic instability, along with a lower propensity for error.

Category: Ankle; Basic Sciences/Biologics; Sports; Trauma Introduction/Purpose: There is a high prevalence of coexisting lateral ankle ligament injuries and syndesmotic ligamentous injuries. However, it is unclear whether syndesmotic ligaments directly contribute toward the stability of the lateral ankle. Dynamic ultrasonography (US) is an imaging modality increasingly used for the care of orthopaedic foot and ankle patients because it allows dynamic evaluation of structures at the point of care with little risk to the patient and at low-cost. The aim of this study is to assess the effect of syndesmotic injury as well as combined syndesmotic and lateral ankle injury on the stability of the lateral ankle. Methods: Sixteen fresh frozen above-knee amputated cadaveric specimens, divided into two groups, underwent ultrasound evaluation for lateral ankle stability. In both the groups, the assessment was first done with all ligaments intact and later with sequential transection of anterior inferior tibiofibular ligament (AITFL), interosseous ligament (IOL), posterior inferior tibiofibular ligament (PITFL), anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL) and posterior talofibular ligament (PTFL). In all scenarios, two loading conditions were considered: (1) Anterior drawer test: 50N and 80N and (2) Lateral clear space (LCS): 1.7Nm torque. The talar translation and LCS to the fixed tibial plafond were measured using Image J. Wilcoxon rank-sum test was used to compare the findings of each ligamentous transection state to the intact state. A p-value

Category: Ankle; Trauma Introduction/Purpose: Syndesmotic instability, when subtle, is challenging to diagnose and often requires visualization of the syndesmosis during applied stress. The purpose of this study was to determine the association between tibiofibular clear space (TFCS) values measured with 1) a portable ultrasound (US) device and 2) fluoroscopy during applied external roation stress for the evaluation of syndesmotic instability. Methods: Eight fresh lower leg cadaveric specimen amputated above the proximal tibiofibular joint were used in this study. Portable US device (Butterfly iQ, Butterfly Network Inc) images and fluoroscopic images taken by a mini C-arm were used to evaluate the ankle syndesmosis in the intact stage, and after sequentially sectioning of the anterior-inferior tibiofibular ligament (AITFL), interosseous ligament (IOL), and posterior-inferior tibiofibular ligament (PITFL) at 7.5Nm torque. A Pearson’s correlation was performed to investigate the correlation between the TFCS among the two modalities. A paired t-test was used to compare TFCS values measured with US or fluoroscopy. Three cadavers were measured by two independent observers to assess reliability of the measurements for each diagnostic modality and analyzed using intraclass correlation coefficients (ICC). P-values of < 0.05 were considered significant. Results: The mean TFCS (+- SD mm) values measured with the US and fluoroscopy are presented in Table 1. TFCS values obtained with the US and fluoroscopy correlated (rho 0.60). Between the imaging modalities similar TFCS values were found in the intact state (difference 0.81+-1.0, p-value 0.061). Compared with fluoroscopy, the TFCS values measured using US increased significantly after sequential transection of the AITFL (0.039), IOL (p=0.004) and PITFL (p

Category: Ankle Introduction/Purpose: To evaluate whether sagittal translation could be detected with ultrasound and arthroscopy and to compare the increasing tibiofibular sagittal translation seen with ultrasound (US) and Arthroscopy. Methods: Eight fresh lower leg cadaveric specimen amputated above the proximal tibiofibular joint were used in this study. The ankle syndesmosis was evaluated using a handheld US device (Butterfly iQ, Butterfly Network Inc, Guilford) and arthroscopy with intact-, and after sequent sectioning of anterior-inferior tibiofibular ligament (AITFL), interosseous ligament (IOL), and posterior- inferior tibiofibular ligament (PITFL). Sagittal plane translation was simulated with 100N of anterior to posterior (A-to-P) and posterior to anterior (P-to-A) hook force which was applied 5cm above of the ankle joint (Figure 1). Pearson’s correlation, one- way repeated measures ANOVA, and Wilcoxon signed-rank test were used for comparison. Three cadavers were measured by two independent observers to assess reliability and analyzed using intraclass correlation coefficients (ICC). Results: A-to-P translation values obtained with US and Arthroscopy had a correlation of -0.14, and P-to-A translation correlation of 0.44. Using US, intact translation was 0.94+-0.62 with A-to-P hook and 0.87+-0.5 with P-to-A hook. Subsequent A- to-P and P-to-A translation increased with 0.07+-0.96mm and 0.04+-0.76 after AITFL cut, with 0.53+-0.9 and 0.15+-0.5 after IOL cut, and with 0.81+-1.3mm and 0.45+-0.8 after PITFL cut (p-values between 0.122 and 0.270) . Using arthroscopy, intact translation was 0.40 +-0.3 with A-to-P hook and 0.99+-0.5 with P-to-A hook. Subsequent A-to-P and P-to-A translation increased from intact with; 0.001+-0.3 and 0.30+-0.4 after AITFL cut, 0.19+-0.4 and 0.74+-0.7 after IOL cut, and 0.40+-0.5 and 1.1+-0.9 after PITFL cut (p-values between 0.005 and 0.037). No statistical differences between US and Arthroscopy were found. Conclusion: US was unable to differentiate between the different stages of injury, even though a similar increase in translation was seen as compared to arthroscopy. Probably this is due to the high variability seen in the US translation values. As US does have several advantages over arthroscopy; availability, non-invasiveness, low costs, and allowance of using the contralateral side as a direct comparison, this technique should be further explored as a potential diagnostic assessment technique of diagnosing occult syndesmotic instability in the sagittal plane.

Category: Ankle; Sports; Trauma Introduction/Purpose: There is a high incidence of concomitance between lateral ankle ligament injuries and syndesmotic ligamentous injuries. However, it is unclear whether syndesmotic ligaments directly contribute toward the stability of the lateral ankle. Stress radiographs are an accepted technique to assess the degree of lateral ankle instability by providing a static view of the ankle when subjected to the anterior drawer (AD) and talar tilt (TT) tests. The aim of this study is to assess the effect of syndesmotic injury as well as combined syndesmotic and lateral ankle injury on the stability of the lateral ankle. Methods: Sixteen fresh frozen above-knee amputated cadaveric specimens, divided into two groups, underwent fluoroscopic evaluation for lateral ankle stability. In both the groups, the assessment was first done with all ligaments intact and later with sequential transection of anterior inferior tibiofibular ligament (AITFL), interosseous ligament (IOL), posterior inferior tibiofibular ligament (PITFL), anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL) and posterior talofibular ligament (PTFL). In all scenarios, two loading conditions were considered: (1) Anterior drawer test: 50N and 80N and (2) Talar tilt and Lateral clear space (LCS): 1.7Nm torque. The talar translation, talar tilt, and LCS were measured using Image J. Wilcoxon rank-sum test was used to compare the findings of each ligamentous transection state to the intact state. A p-value

Category: Ankle; Arthroscopy; Sports; Trauma Introduction/Purpose: Numerous studies have shown a high incidence of associated lateral ankle and syndesmotic ligamentous injuries. It is unclear, however, if there is a direct contribution of the lateral ligaments towards stabilizing the syndesmosis. Using arthroscopy, we assessed to what extent lateral ankle ligaments contribute to syndesmotic stability in the coronal and sagittal plane. Our hypothesis was that lateral ankle ligament injury has effect on syndesmosis instability. Methods: Sixteen fresh frozen above-knee amputated cadaveric specimens were divided into two groups that underwent arthroscopic evaluation for syndesmotic stability. In both the groups, the assessment was done with all syndesmotic and ankle ligaments intact and later with sequential transection of the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), the posterior talofibular ligament (PTFL), anterior inferior tibiofibular ligament (AITFL), the interosseous ligament (IOL) and the posterior inferior tibiofibular ligament (PITFL). In all scenarios, coronal and sagittal loading conditions were considered under 100N of direct force to fibula. The measurements of the distal tibiofibular coronal plane space at the anterior and posterior third of syndesmosis were performed using arthroscopic probes with increment of 0.2mm diameter. Further the sagittal translation were measured by arthroscopic scaled probe. Dunnett test was used to compare the findings of each ligamentous transection state to the intact state. A p-value < 0.05 was considered significantly defferent. Results: Compared with the intact ligamentous state, there was no difference in coronal and sagittal stability when the lateral ankle ligaments (ATFL, CFL, PTFL) and AITFL were transected (Table1 and 2, Group1). However, after subsequent transection of the IOL, or after transection of the lateral ankle ligaments (ATFL, CFL or and PTFL) alongside the AITFL and IOL, both coronal space and sagittal translation increased as compared with the intact state (p-values p

Category: Ankle Introduction/Purpose: Diagnosing syndesmotic instability, especially when subtle, remains challenging. Weight bearing computed tomography (WBCT) offers a unique opportunity to evaluate the distal syndesmosis under physiologic load while simultaneously comparing the injured and uninjured side. We hypothesized that WBCT volumetric measurements of the distal syndesmosis were increased on the injured side as compared to the contralateral uninjured side among patients with syndesmotic instability. Our secondary hypothesis was that these 3-dimensional calculations were an even more sensitive determinant of instability as compared to 2-dimensional methodology. Methods: Twelve patients with unilateral syndesmotic instability requiring operative fixation who underwent preoperative bilateral foot and ankle WBCT were included in the study group. The control group comprised of 24 patients without ankle injury who underwent similar imaging. For each WBCT scan, 2-dimensional measurements of the interspace between the distal fibula and tibia were measured 1cm above the joint line in the axial plane, namely the syndesmosis area and the direct anterior, middle and posterior difference. Furthermore, three volumetric measurements of the interspace between the distal fibula and tibia were evaluated: 1) from the tibial plafond extending until 3cm proximally, 2) 5cm proximally, and 3) 10cm proximally from the joint line. Results: In patients with unilateral syndesmotic instability, all weightbearing volumetric measurements were significantly larger on the injured side as compared to the contralateral, uninjured side (p

Category: Sports; Ankle Introduction/Purpose: Destabilizing injuries to the lateral ligament have relied on physical examination and radiographic stress test for diagnosis, with a focus on anterior translation and tilting of the talus relative to the tibial bone. Portable ultrasonography (PUS) has increasingly been used in the clinical setting, allowing dynamic and non-invasive evaluation. The primary aim of this study was to assess the anterior translation and tilting of the talus with PUS in various stages of lateral ankle ligamentous injury. Secondary, we compared the instability values measured with PUS with those measured on fluoroscopy. Third, we aimed to determine the optimal cutoff values of the PUS that distinguish stable from unstable state. Methods: 8 fresh-frozen cadaveric specimens underwent PUS and fluoroscopic evaluation for lateral ankle stability. The assessment was done with all ligaments intact and later with sequential transection of the anterior-talofibular ligament (ATFL), the calcaneofibular ligament (CFL), and the posterior-talofibular ligament (PTFL). In all scenarios, 2 loading conditions were considered; 1) Performing the anterior drawer test under 50N and 80N of force, anterior translation was measured with PUS and fluoroscopy; 2) Performing the talar tilt test under 1.7Nm of torque, the lateral clear space (the distance between the fibular tip and lateral process of the talus) was measured with PUS, and the talar tilt angle was measured with fluoroscopy (Figure1). Pearson’s and Spearman’s rank correlation was used to determine the correlation. Youden’s J statistic was used to determine the optimal cutoff values for the PUS to distinguish intact or ATFL injury versus ATFL-CFL or ATFL-CFL-PTFL injuries under various loading conditions. Results: Strong positive correlations were found between PUS and fluoroscopic measurements (Pearson correlation:r=0.78- 0.85). PUS and fluoroscopic measurements during anterior translation and talar tilt test increased as additional ligaments were transected (Spearman’s rank correlation: anterior translation; r=0.74, p < 0.001: talar tilt; r=0.81, p=0.8). The optimal PUS cutoff values for distinguishing intact or ATFL injury from ATFL-CFL or ATFL-CFL-PTFL injuries were >=3.40mm (sensitivity 87.5%, specificity 81.25%) and >=4.78mm (sensitivity 87.5%, specificity 81.25%) of anterior talar translation under 50N and 80N of force respectively, as well as >=3.09mm (sensitivity 75%, specificity 93.75%) of the lateral clear space under 1.7Nm of torque. Conclusion: Portable ultrasonography for the diagnosis of lateral ankle instability was strongly correlated with fluoroscopic findings, and thus, can be a valuable diagnostic tool at the point of care. We recommend future in vivo research to investigate the accuracy of this new ultrasound application in a clinical setting.

Category: Ankle; Sports; Trauma Introduction/Purpose: About one-fifth of all patients diagnosed with an ankle sprain also suffer a ligamentous injury of the ankle syndesmosis. Despite the common concomitant injuries, it is still unclear whether there is a direct contribution of the lateral ligaments towards stabilizing the syndesmosis. Portable ultrasonography (PUS) has increasingly been used in the clinical setting, allowing dynamic and non-invasive evaluation at the point of care. The primary aim of this study was to assess to what extent lateral ankle ligaments contribute to syndesmotic stability in the sagittal and rotational plane using PUS. Secondary, we determine if PUS is a reliable tool for the assessment of syndesmotic instability. Our primary hypothesis was that lateral ankle ligaments contribute significantly to the stability of the ankle syndesmosis. Methods: 16 fresh-frozen cadaveric specimens were equally divided into 2 groups that underwent PUS evaluation for syndesmotic stability. The assessment was done at the intact state and later with sequential ligament transection. In group 1, the anterior talofibular ligament (ATFL) was transected, followed by the calcaneofibular ligament (CFL), the posterior talofibular ligament (PTFL), the anteroinferior tibiofibular ligament (AITFL), the interosseous ligament (IOL), and the posteroinferior tibiofibular ligament (PITFL). In group 2, the transection started with the AITFL then followed by the ATFL, the CFL, the IOL, the PTFL, and the PITFL. PUS measurements were performed during anterior to posterior (AP), posterior to anterior (PA), and external rotated loading condition (Figure 1). One-way ANOVA and post hoc Dunnett test were used to compare the findings of each state to the intact. Besides, we assessed the inter-rater and intra-rater reliability using the intraclass correlation coefficient (ICC) through a two-way mixed-effects model. Results: In group 1, showed that compared to the intact stage, fibular translation in the sagittal plane and the anterior tibiofibular clear space (TFCS) distance did not increase after transection of all three lateral ankle ligaments. However, the syndesmotic PUS measurements did increase after subsequent transection of the AITFL and IOL (p-values ranging from 0.047 to

Category: Ankle; Sports; Trauma Introduction/Purpose: To evaluate syndesmotic instability by measuring the tibiofibular clear space (TFCS) opening using a portable ultrasound device. In addition, we assessed the optimal amount of external rotation torque required to detect syndesmotic instability. Methods: Eight fresh lower leg cadaveric specimen amputated above the proximal tibiofibular joint were used. Using a portable ultrasound device (Butterfly iQ, Butterfly Network Inc) the ankle syndesmosis was evaluated in the intact stage, and after sequentially sectioning of the anterior-inferior tibiofibular ligament (AITFL), interosseous ligament (IOL), and posterior-inferior tibiofibular ligament (PITFL)(Figure 1). In each ligamentous sectioning stage TFCS in millimeter (mm) was measured with ultrasound while consecutively 0N, 45N, 60N, 75N, and 90N external rotation directed torque was applied to the ankle. To evaluate which amount of torque would be sufficient to detect syndesmotic instability the delta increase of TFCS opening at different states of torque compared to the unstressed state was calculated. One-way repeated measures ANOVA was used to detect whether an increase in delta-TFCS opening could be detected between the intact state and consecutive syndesmotic ligament transection stages. Correction for multiple comparisons was performed using the Bonferroni-Holm correction. Results: Under all torque-loading conditions TFCS (mean+-SDmm) opening increased as additional syndesmosis ligaments were transected (p-values

Category: Trauma; Ankle; Sports Introduction/Purpose: Traumatic injuries to the distal tibiofibular syndesmosis are relatively common and can be associated with ankle fractures or occur as purely ligamentous injuries. Unstable syndesmotic injuries require surgical repair, generally performed using either screw or suture button fixation. The superiority of either fixation method remains a subject of ongoing debate. The aim of this study is to compare both clinical and radiographic outcomes of screw and suture button fixation of syndesmosis instability using Patient-Reported Outcomes Measurement Information System (PROMIS) and weight bearing CT scan (WBCT). Methods: Medical records were reviewed to identify patients who had a unilateral syndesmotic injury requiring surgical stabilization and who were at least one year out from injury. Exclusion criteria included patients less than 18 years old, ipsilateral pilon fracture, history of contralateral ankle or pilon fracture or syndesmosis injury, BMI >40, and any neurological impairment. Twenty eligible patients were recruited to complete PROMIS questionnaires and undergo bilateral WBCT scan of both ankles, divided into two groups. In the first group (n=10) the patients had undergone screw fixation of the syndesmosis, while in the second group (n=10) the syndesmosis was fixed using a suture button construct. All patients completed PROMIS questionnaires for pain intensity, pain interference, physical function and depression. Radiographic assessment was performed using axial images of WBCT scan of both the injured ankle and the contralateral normal side at a level one cm proximal to the tibial plafond ( Figure 1 ). Results: At an average follow up of three years, none of the recruited patients required a revision surgery. There was no significant difference between the two groups in terms of the four PROMIS questionnaires (P values ranged from 0.17 to 0.43). In the suture button group, the measurements of the injured side were significantly different from the normal side for the syndesmotic area (P=0.003), fibular rotation (P=0.004), anterior difference (P=0.025) and direct anterior difference (P=0.035). Other measurements of posterior difference, middle difference, direct posterior difference and fibular translation were not significantly different (P values ranged from 0.36 to 0.99). In the screw fixation group, the syndesmotic area was the only significantly different measurement in the injured side as compared to the normal side (P=0.006). Conclusion: Screw and suture button fixation for syndesmotic instability have similar clinical outcomes at average three years follow up as measured by PROMIS scores. Both screw and suture button did not entirely restore the syndesmotic area as compared to the contralateral normal ankle, suggesting some residual diastasis on weight bearing CT. In addition, as compared to screw fixation, the suture button did not seem to restore the normal fibular rotation, with residual external rotation of the fibula noted. Longer clinical follow up is necessary to understand the clinical implication of such malreduction.

Category: Ankle Introduction/Purpose: Prompt management of syndesmotic instability is critical for optimizing clinical outcome, but subtle injuries may be difficult to diagnose. Application of modern imaging modalities such as weight bearing CT (WBCT) may better identify such injuries by virtue of assessing the distal tibiofibular articulation under physiologic load. The aim of this study was to evaluate the distal tibiofibular articulation using WBCT among patients with known syndesmotic instability and compare these findings with their uninjured contralateral sides, and thereafter corroborate such measurement differences with patients devoid of any syndesmotic injury. Methods: Patients with unilateral syndesmotic instability requiring surgical fixation (n=12) underwent bilateral ankle WBCT that incorporated the entire foot. A separate cohort of patients without ankle injury also underwent bilateral ankle WBCT for assessment of either a Lisfranc injury or forefoot condition (n=24). All WBCT imaging was performed preoperatively. A set of five axial plane tibiofibular joint measurements including one angular measurement were standardly assessed one cm above the tibial plafond. Values were recorded by two independent observers to assess for interobserver reliability scores. Interpretation of the intraclass correlation coefficients was carried out according to the guidelines proposed by Shrout: 0.00-0.10 virtually none, 0.11-0.40 slight, 0.41-0.60 fair, 0.61-0.80 moderate, 0.81 -1.00 substantial. Results: Among the control population without ankle injury, no differences were found between bilateral measurements (p-value range 0.172 - 0.961). Among those with known unilateral syndesmotic instability, values differed between the injured and uninjured side in five of six measurements— including syndesmotic area, direct anterior-, middle-, and posterior- difference, and sagittal translation (p

Category: Ankle, Sports, Trauma, Syndesmosis. Introduction/Purpose: Accurate reduction of the syndesmosis is essential to the restoration of normal ankle mechanics, but radiographic evaluation of reduction quality has been demonstrably unreliable. CT imaging has traditionally been considered the gold standard, but there is no uniformly accepted method by which to assess syndesmotic reduction on CT. The aim of this study was to evaluate intra- and interobserver reliability of published measurements for evaluation of syndesmosis reduction using weight-bearing CT scan. Methods: Medical records were reviewed to identify patients who underwent surgical stabilization of a unilateral syndesmotic injury. Exclusion criteria included patients less than 18 years old, ipsilateral pilon fracture, history of contralateral ankle or pilon fracture or syndesmosis injury, BMI >40, and any neurological impairment. Twenty eligible patients were recruited to participate in the study and underwent weight-bearing CT evaluation for both ankles simultaneously. The quality of syndesmotic reduction was evaluated using axial CT images at a level 1 cm proximal to the tibial plafond using nine published radiological measurements (Figure 1). Inter- and intraobserver reliability were assessed for each evaluation method. Side by side method (qualitatively observing the repaired laterality side by side with the contralateral control) was assessed using Kappa interrater agreement, while the reliabilities for all other continuous methods were assessed with interclass correlation coefficients (ICC). Results: The study cohort consisted of ten males and ten females with mean age of 43 years (range, 23-67 years). The intraobserver reliability of the side by side method was 0.49 and 0.24 for the first and second observers respectively, and the interobserver reliability was 0.24. The syndesmotic area showed the highest interobserver reliability (0.96), the highest intraobserver reliability for observer 2 (0.97), and the second highest intraobserver reliability for observer 1 (0.92). Fibular rotation had the second highest interobserver reliability in our results (0.84), with high intraobserver reliability of 0.91 and 0.8 for first and second observers, respectively. The other six radiological measurements had interobserver reliability that ranged between 0.62 and 0.83. Conclusion: Qualitatively assessing syndesmotic reduction via side by side comparison with the uninjured ankle had the least intra- and interobserver reliability and should not be relied upon to determine syndesmotic reduction quality. In contradistinction, syndesmotic area calculation showed the highest reliability for evaluating syndesmosis reduction, followed by fibular rotation. Additional efforts should be considered to standardize such measurements within CT image viewers, so they become seamlessly accessible in the clinical setting.

Category: Ankle Introduction/Purpose: Syndesmotic instability, when subtle, is challenging to diagnose and often requires visualization of the syndesmosis during applied stress. Ultrasound is a dynamic, non-invasive diagnostic tool that can achieve this at the point of care, although accurate assessment requires better understanding of normal physiologic motion. The aim of this study is to assess normal distal tibiofibular motion in the sagittal plane using ultrasound during applied stress. Methods: Patients with no history of injury to either ankle were included in this study. The distal tibiofibular joint was examined using an ultrasound probe placed anteriorly with the patient in supine position and posteriorly with the patient in prone position. Sagittal fibular translation was simulated by applying an increasing manual force to the fibula in the sagittal plane: 1) in the supine position, anterior to posterior (SAP), 2) in the prone position, posterior to anterior (PPA), and 3) in the prone position, anterior to posterior (PAP) (Figure 1). The relative position of the fibula and tibia were subsequently measured without force application and then at maximum force application, defined as the end point at which increased force did not result in additional fibular translation. Fibular displacement in cm was thereafter calculated. A linear mixed effect model was built for analysis, wherein subject, examiner, experiment and side were random factors. Results: A total of 34 ankles were included. Mean age was 25.0±5 years and 71% were male. After adjusting for gender and side, the model showed that the application of force led to fibular motion in the sagittal plane for each measurement technique. SAP, coef. 0.06 [0.06-0.07], p-value < 0.001. PPA, coef. 0.04 [0.03-0.05], p-value < 0.001. PAP, coef. -0.16 [-0.17- -0.15], p-value < 0.001. The model also showed similar fibular motion values for left and right measurements, SAP p-value 0.589, PPA p-value 0.236, PAP p-value 0.104. Fibular movement values also were not influenced by gender, SAP p-value 0.348, PPA p-value 0.613, PAP p-value 0.714. Conclusion: Alterations of syndesmotic motion in the sagittal plane can be successfully identified using dynamic ultrasound under stressed conditions. On average, 0.6 mm of A to P translation and 0.4 mm of P to A translation were found. Equivalent translation values between the left and right side in each patient underscores that, in the injured setting, the contralateral ankle may be used as a reliable control. This establishes a normal value for ultrasound examination of the syndesmosis, allowing future studies examining the injured state.

Category: Ankle Introduction/Purpose: Syndesmotic instability, when subtle, is challenging to diagnose and requires visualization of the syndesmosis during an applied stress. Ultrasound is a dynamic, non-invasive diagnostic tool that can do so at the point of care, but its reliability and reproducibility remain unclear. The aim of this study is to evaluate reliability and reproducibility of the dynamic use of ultrasonography, a safe and non-invasive imaging technique, for evaluating tibiofibular translation in the sagittal plane. Methods: Patients with no history of injury to either ankle were included in this study. The distal tibiofibular joint was examined using an ultrasound probe placed anteriorly with the patient in supine position, and posteriorly with the patient in prone position. Sagittal fibular translation was simulated by applying an increasing manual force to the fibula in the sagittal plane: 1) in supine position, anterior to posterior (SAP), 2) in prone position, posterior to anterior (PPA), and 3) in prone position, anterior to posterior (PAP) (Figure 1). Two examiners performed the dynamic examination independently to investigate reproducibility of the test. To test for reliability, the relative position of the fibula and tibia were subsequently measured by three observers; with no force application and at maximum force application, defined as the end point at which increased force did not result in additional fibular translation. Interrater reliability was tested using intraclass correlation coefficients (ICC). Results: In total 34 ankles among 17 patients were included, of which 24 ankles were male (71%). Mean subject age was 25.0 ± 5 years. Substantial agreement was found for all measurements. Anterior measurements of the distance between the ultrasound probe and the tibia and fibula demonstrated ICC’s of 0.98 and 0.98, respectively. PPA demonstrated ICC’s of 0.99 and 0.99, and PAP ICC’s of 0.99, and 0.99. To test for reproducibility the mean tibiofibular delta values of SAP, PPA, and PAP in neutral, and after maximum force application were compared between exams. Exam 1 vs exam 2: SAPneutral, coef. -0.001, p-value 0.895. PPAneutral, coef. -0.06, p-value 0.076. PAPneutral, coef. -0.01, p-value 0.957. SAPmaxforce, coef. -0.03, p-value 0.365. PAPmaxforce, coef.

Category: Ankle, Sports, Trauma, Syndesmosis Introduction/Purpose: Traumatic injuries to the distal tibiofibular syndesmosis are relatively common and can be associated with ankle fractures or occur as purely ligamentous injuries. Unstable syndesmotic injuries require surgical repair, generally performed using either screw or suture button fixation. The superiority of either fixation method remains a subject of ongoing debate. The aim of this study is to compare both clinical and radiographic outcomes of screw and suture button fixation of syndesmosis instability using Patient-Reported Outcomes Measurement Information System (ROMIS) and weight bearing CT scan (WBCT). Methods: Medical records were reviewed to identify patients who had a unilateral syndesmotic injury requiring surgical stabilization and who were at least one year out from injury. Exclusion criteria included patients less than 18 years old, ipsilateral pilon fracture, history of contralateral ankle or pilon fracture or syndesmosis injury, BMI >40, and any neurological impairment. Twenty eligible patients were recruited to complete PROMIS questionnaires and undergo bilateral WBCT scan of both ankles, divided into two groups. In the first group (n=10) the patients had undergone screw fixation of the syndesmosis, while in the second group (n=10) the syndesmosis was fixed using a suture button construct. All patients completed PROMIS questionnaires for pain intensity, pain interference, physical function and depression. Radiographic assessment was performed using axial images of WBCT scan of both the injured ankle and the contralateral normal side at a level one cm proximal to the tibial plafond (Figure 1). Results: At an average follow up of three years, none of the recruited patients required a revision surgery. There was no significant difference between the two groups in terms of the four PROMIS questionnaires (P values ranged from 0.17 to 0.43). In the suture button group, the measurements of the injured side were significantly different from the normal side for the syndesmotic area (P=0.003), fibular rotation (P=0.004), anterior difference (P=0.025) and direct anterior difference (P=0.035). Other measurements of posterior difference, middle difference, direct posterior difference and fibular translation were not significantly different (P values ranged from 0.36 to 0.99). In the screw fixation group, the syndesmotic area was the only significantly different measurement in the injured side as compared to the normal side (P=0.006). Conclusion: Screw and suture button fixation for syndesmotic instability have similar clinical outcomes at average three years follow up as measured by PROMIS scores. Both screw and suture button did not entirely restore the syndesmotic area as compared to the contralateral normal ankle, suggesting some residual diastasis on weight bearing CT. In addition, as compared to screw fixation, the suture button did not seem to restore the normal fibular rotation, with residual external rotation of the fibula noted. Longer clinical follow up is necessary to understand the clinical implication of such malreduction.

Category: Opioid consumption rate and risk factors investigation after foot and ankle surgery Introduction/Purpose: The rapid increase in the consumption of prescription opioids has become one of the leading medical, economical, and sociological burdens in North America. In the United States, orthopedic surgery is the fourth leading specialty in the number of opioids prescribed, and the largest among surgical specialties. There is insufficient evidence to guide surgeons about appropriate opioid prescription amounts after orthopaedic foot and ankle (F&A) procedures. The aim of this study was to determine the opioid consumption rate after foot and ankle procedures, and to identify patient risk factors associated with higher use. Methods: A total of 535 patients who underwent a F&A surgery performed by one orthopedic surgeon from August 2016 to March 2018 were investigated. The study was approved by our IRB. Each patient received a preoperative discussion about postoperative pain and expectations alongside a standardized handout. At the two-week postoperative visit, the patient-reported amount of consumed opioids was recorded. Prescription details, the amount of opioids taken, refill requests, pain-issue related telephone calls, and additional MD/ED visits were also documented. Patient demographics and co-morbidities, use of regional anesthesia, postoperative inpatient hospitalization, surgery type and severity, and pre-operative opioid use were collected retrospectively. Total amounts of morphine equivalents were calculated and converted into oxycodone 5 mg pills for standardization. P-values of

Category: Other Introduction/Purpose: When passively correctible, adult acquired flatfoot deformities (AAFD) are often treated with joint-sparing procedures. Questions remain, however, as to the efficacy of such flexible procedures when clinical deformities become more severe. In patients with increasingly severe deformities, a primary fusion may lead to more predictable outcomes, but also risks nonunion. The primary aim of this study was to compare the reoperation rates and complication rates following flexible reconstructions versus fusion procedures in the treatment of flexible AAFD. Methods: All patients, who were diagnosed and treated surgically for a flexible AAFD between January 1, 2001 and January 1, 2016, were identified. Exclusion criteria included incomplete medical records, rigid flatfoot deformities, and prior flatfoot surgery. Procedures defined as flexible reconstructions included medial calcaneal osteotomy (MCO), lateral calcaneal lengthening (LCL), double osteotomy, posterior tibial tendon (PTT) debridement, or PTT augmentation; procedures defined as fusions included subtalar (ST) arthrodesis, talonavicular (TN) arthrodesis, calcaneocuboid (CCJ) arthrodesis (alone or in combination with a LCL), double arthrodesis, or triple arthrodesis. Patient demographics, type of surgical procedure, postoperative complications, and reoperation rates were collected. Bivariate analysis was performed to compare patients who had a flexible reconstruction procedure versus a fusion procedure. Results: Two-hundred-thirty-nine patients (255 feet, mean follow up 62±50 months, range 15-104) were included. Two-hundred-eight (87%) patients underwent a flexible reconstruction, average age 55 (±12.0), while 31 (13%) patients underwent a fusion, average age 58 (±14.4) (p = 0.161). Age, BMI, diabetes and neuropathy rates were similar for both groups. Fifty-four patients (24%) underwent a flexible reconstruction and returned to the OR versus 11 (34%) in the fusion group (p = 0.217). Nonunion occurred more in the fusion group, with 5 (16%) versus 10 (4%) nonunions in the flexible reconstruction (p = 0.027). Symptomatic nonunion rates were similar. Rates of surgical revision for nonunion among patients returning to the OR were similar between flexible (7/54, 3%) and fusion (3/11, 9%) groups (p = 0.117). Conclusion: No significant difference in reoperation rates was found between flexible AAFD patients who were treated with flexible reconstructions versus fusions. As expected, the nonunion rate was significantly higher in the fusion group. Notably, rates of revision surgery for nonunion were similar between groups. Our findings suggest that nonunion should be less of a concern when considering a flexible versus fusion procedure for patients with a severe AAFD, and that other factors such as the degree of deformity should guide decision making.

Category: Midfoot/Forefoot Introduction/Purpose: Proximal fifth metatarsal fractures (PFMF) are among the most common fractures of the foot, and may be subdivided into tuberosity avulsion fracture, Jones fracture, and proximal diaphyseal fracture. However, for Jones fractures and proximal diaphyseal fractures optimal treatment is still debated in literature. The Torg criteria are used in deciding to treat surgically or conservative, whereby Torg type I and II indicates conservative treatment, and type III indicates surgical treatment. Yet failure rates of both management options vary and derive from small study groups. The aim of this study was to compare failure rates after surgical- and conservative treatment of Jones fractures and proximal diaphyseal fractures, to evaluate the incidence of treatment failure, and to assess factors associated with healing difficulties of PFMF. Methods: A total of 1,133 adult patients that were diagnosed and treated for PFMF between 2005 and 2015 in a tertiary care foot and ankle referral center were included. Retrospective chart review recorded patient demographics, suspected risk factors for impaired healing of PFMF (rheumatoid arthritis, diabetes mellitus, osteoporosis, nutritional and hormonal disorders, foot deformities, (neuropathic) arthropathy of the foot and/or ankle and peripheral neuropathy of the lower extremity), and treatment indication. Multivariable logistic regression analysis was used to determine factors associated with healing difficulties. Propensity score matching was used to minimize selection bias between treatments in Jones fractures and proximal diaphyseal fractures. Results: In total, 489(43.2%) patients were diagnosed with a tuberosity avulsion fracture, 391(34.5%) patients with a Jones fracture and 253(22.3%) patients with a proximal diaphyseal fracture. In the tuberosity fracture group, a nonunion was found in 5.3%(25/473) of the patients treated conservatively and in 0%(0/16) treated operatively. For the Jones fractures and proximal diaphyseal fractures the non-union rate for conservative treatment was 10%(35/337) and 5.9%(14/238), and for surgical treatment 11%(6/54) and 0%(0/15), respectively. No independent risk factors for complicating the healing process of PFMF were identified. With propensity score matching, 37 patients treated operatively were matched to 37 patients undergoing conservative treatment. The risk for a nonunion was lower in the operative group compared to the conservative treatment group (relative risk 0.8, P=0.006). Conclusion: In this propensity-matched cohort, surgical treatment for Jones fractures and proximal diaphyseal fractures were associated with better fracture healing compared to conservative treatment. In addition, no factors were found to be associated with healing difficulties of proximal fifth metatarsal fractures.

Category: Other Introduction/Purpose: Amid the current opioid epidemic in the United States, surgeons are forced to more carefully manage postoperative pain prescriptions. Despite the enthusiastic engagement of physicians, politicians and the general public, however, clear guidelines for opioid prescribing postoperatively still do not exist, including after foot and ankle surgery. Given the ablity to improve patient outcomes by decreasing treatment variability in other realms of medicine, this study sought to quantify the postoperative opioid prescribing regimens of American foot and ankle surgeons as an initial step towards understanding prescription patterns and establishing a baseline regimen from which future guidelines may stem. Methods: A total of 1235 active and candidate members of the American Orthopaedic Foot & Ankle Society (AOFAS) from the United States and Canada were invited to fill out a postoperative pain management survey using a Research Electronic Data Capture (REDCap) web-based application. Surgeons were asked to report on their pain prescription regimens, including type and number of pills, after nine common foot and ankle procedures rated as minor, moderate, or major in severity. The presence of a regional block anesthesia was also recorded. Opioid prescriptions were then converted to the equivalent of 5 mg oxycodone pills for standardization and inter-prescriber comparison. Results: Two hundred twenty-four (18%) surgeons completed the survey. Because of highly skewed data results are reported as medians and the range. Postoperative opioid prescriptions, given in oxycodone 5 mg pill equivalents, were as follows: 39 (8-133) pills for minor procedure, 45 (10-180) pills for a moderate soft tissue procedure, 53 (16-186) pills for a moderate bony procedure, and 60 (20-200) pills for a major bony procedure. Conclusion: Wide variation between surgeons was noted in postoperative pain management. Median prescription opioid doses vary from 39 to 60 oxycodone pills depending on procedure type. It is likely that the amount of opioids prescribed is excessive for adequate pain management, especially for smaller procedures. We propose a post-operative pain regimen that limits the number of pills prescribed based on studies from other surgical specialties. Future studies are necessary to assess the efficacy of current postoperative pain management practices and to guide improved pain management that limits the use of opioids where possible.