Diagnostic Accuracy of Conventional Ankle CT Scan With External Rotation and Dorsiflexion in Patients With Acute Isolated Syndesmotic Instability

Category: Ankle; Sports Introduction/Purpose: Syndesmotic injury in an athletic population is associated with a prolonged ankle disability after an ankle sprain and often requires a longer recovery than a lateral collateral ligament injury. Although several imaging tests are available, diagnosing syndesmotic instability remains challenging. The main objective was to determine the diagnostic accuracy of conventional ankle computed tomography (CT) scans with the joint in external rotation and dorsiflexion and compare it with that of conventional ankle CT scans in a neutral position. Methods: Between September 2018 and April 2021, this prospective study consecutively included adults visiting the foot and ankle outpatient clinic with a positive orthopedic examination for acute syndesmotic injury. Participants underwent 3 CT scan tests. First, ankles were scanned in a neutral position. Second, ankles were scanned with 45° of external rotation, dorsiflexion, and extended knees. Third, ankles were scanned with 45° of external rotation, dorsiflexion, and flexed knees. Three measurements, comprising rotation (measurement a), lateral translation (measurement c), and anteroposterior translation (measurement f) of the fibula concerning the tibia, were used to diagnose syndesmotic instability in the 3 CT scans. Magnetic resonance imaging was used as a reference standard. The area under the curve (AUC) was used to compare the diagnostic accuracy, and Youden’s J index was calculated to determine the ideal cutoff point. Results: Images obtained in 68 participants (mean age, 36.5 years; range, 18-69 years) were analyzed, comprising 36 syndesmotic injuries and 32 lateral collateral ligament injuries. The best diagnostic accuracy occurred with the rotational measurement a, in which the second and third CT scans with stress maneuvers presented greater AUCs (0.97 and 0.99) than the first CT scan in a neutral position (0.62). The ideal cutoff point for the stress maneuvers was 1.0 mm in the rotational measurement and reached a sensitivity and specificity of 83% and 97% for the second CT scan with extended knees and 86% and 100% for the third CT scan with flexed knees, respectively. Conclusion: Conventional ankle CT with stress maneuvers has excellent performance for diagnosing subtle syndesmotic rotational instability, as it shows a greater AUC and enhanced sensitivity at the ideal cutoff point compared with ankle CT in the neutral position

The Role of Computed Tomography with External Rotation and Dorsiflexion in Decision Making for Acute Isolated Posterior Malleolar Fractures Bartoníček and Rammelt Type II: A Cross-Sectional Study

Category: Ankle; Sports Introduction/Purpose: A ligament-centered analysis is currently incorporated in the assessment of joint stability in malleolar fractures. Although several imaging tests are available, in the setting of acute isolated non-displaced posterior malleolar fractures Bartoníček/Rammelt types II and IV diagnosing syndesmotic instability remains challenging. The objective of this multi-center cross- sectional study was to evaluate the syndesmotic and fracture instability using conventional ankle CT with external rotation and dorsiflexion in the setting of acute, isolated non-displaced Bartoníček and Rammelt type II posterior malleolar fractures. Methods: Between March 2018 and September 2022, a consecutive sample of 123 individuals with an ankle sprain were assessed for eligibility. In total, 33 participants met the inclusion criteria. All participants underwent a CT scan (CTSM), comprising a first phase with the ankles in a neutral position, then a stress phase with the ankles in external rotation and dorsiflexion and semiflexed knees. Investigators used the patterns of ligament tear found at MRI and instability at CTSM to classify all participants into West Point grades I, IIA, IIB, or III. Mann-Whitney test was used to test the differences in the numerical variables between injured and uninjured syndesmoses. The Spearman correlation tested the strength of the association between the tibial joint surface involved in posterior malleolus fracture and syndesmotic instability. Results: In MRI reading parameters two patterns of syndesmotic ligament injury predominated. A completely torn AITF and IO ligaments and a completely torn AITF was combined with a partially torn IO. Regarding the deep layer of the deltoid ligament, participants were classified as normal, strained and partially torn. In CT scan reading parameters in the neutral phase, the median difference of 0.2 mm in d measurements between injured and uninjured syndesmoses was not statistically significant (P = 0.057). During the stress phase, the injured and uninjured syndesmoses had distinct behavior, and the 2.3 mm median difference for d measurement was statistically significant (P < 0.0001). Conclusion: The conventional computed tomography with external rotation and dorsiflexion represent a reproducible and accurate diagnostic option for the detection of syndesmosis instability and fracture instability in acute isolated posterior malleolar fractures Bartonícek and Rammelt type II

Multiligament Ankle Instability Following Rotational Ankle Injuries: A Prospective Cohort Study

Category: Sports; Arthroscopy Introduction/Purpose: Rotational ankle injuries are frequent and mostly benign. However, chronic pain and residual instability following an index rotational trauma can happen. The diagnostic elucidation of the pain source is challenging, with ligamentous insufficiency, osteochondral injuries, and impingement/arthritis representing potential causes for symptoms. The prevalence and pattern of the residual isolated or combined ligamentous ankle instability following rotational injuries are not entirely elucidated in the literature. In this prospective cohort study, we aimed to assess the frequency of combined ligamentous instability (lateral, medial, and syndesmotic) in patients with chronic ankle pain (>6 months) following rotational ankle injuries that failed conservative treatment and underwent surgical treatment. We also aimed to assess improvement in patient-reported outcomes (PROs) following treatment of the diagnosed conditions. Methods: IRB-approved prospective cohort study. We included patients with history of chronic pain (>6 months) following a rotational ankle injury, with clinical signs of combined ligamentous instability of at least two ligamentous complexes (lateral, medial, and syndesmotic), and that failed conservative treatment (>3 months). All patients underwent surgical treatment. Diagnostic arthroscopic assessment was performed. Syndesmotic instability was considered positive if a metallic sphere of 3mm could be inserted in the anterior syndesmotic space. Deep deltoid instability was confirmed with a “pass-through sign” when a 4.0mm shaver could be introduced in the medial gutter. Lateral ankle instability was confirmed with a positive rotatory drawer test under fluoroscopic assessment. Presence of isolated or combined ligamentous instability was noted and patients received appropriate open surgical treatment for the confirmed ligamentous insufficiencies. Presence of associated osteochondral injuries, peroneal pathology and anterior bony impingement was also recorded. PROs were collected pre-operatively and at most recent follow-up. Results: A total of 27 patients were included (9 males/18 females), mean age 35.9 years (range, 18-68) and average BMI 31.3kg/m 2 (CI, 28.1-34.5). Eighty-nine percent had ankle sprains, and 11% rotational ankle fractures treated conservatively. Intraoperative assessment demonstrated positive lateral, medial, and syndesmotic instability in respectively 96%, 81%, and 78% of the patients. Most common combined instabilities were: 59% multidirectional (all three complexes), 19% rotational (medial+lateral), 15% anterolateral (lateral+syndesmotic), and 4% anteromedial (medial+syndesmotic). Isolated lateral instability was present in only one patient (4%). Peroneal tendon pathology, osteochondral injuries and anterior bony impingement were found in respectively 67%, 19%, and 26% of the patients. The average postoperative follow-up was 22.2 months (3-39 months). Significant improvements in VAS (P=0.0024), PROMIS Pain Interference (p=0.024), and EFAS scores (p=0.022) were observed. Conclusion: In this prospective cohort study, combined multiligament instability was extremely frequent in patients with chronic pain following rotational ankle injuries. Ninety-six percent of patients had confirmed intraoperative instability of at least two of the three ankle ligamentous complexes. Multidirectional (lateral, medial, and syndesmotic) (49%), rotational (lateral and medial) (19%), and anterolateral (syndesmotic and lateral) (15%) instabilities were the most frequent injury patterns. Following ligamentous repair/reconstruction, significant improvements in PROs were observed at an average follow-up of 22-months. Our study highlights that the diagnosis of residual multiligament ankle instability should be considered in patients with chronic ankle pain following rotational injuries

Semi-Automatic 3D Assessment of Zadek Osteotomy Effects

Category: Hindfoot; Sports Introduction/Purpose: Zadek's procedure is a surgical option to treat insertional Achilles tendinopathy(IAT). This procedure consists of a closing wedge osteotomy of the calcaneus with biomechanical consequences. Great modifications in the hindfoot alignment can result in poor functional outcomes for athletes. Additionally, some authors stated that Zadek osteotomy is a good choice for patients with IAT associated with cavovarus foot. This study aims to analyze the hindfoot alignment and the parameters related to Haglund's syndrome after Zadek's osteotomy using a virtual surgical simulation by specific software. The authors hypothesize that the Zadek is an effective technique to decompress the Achilles tendon against the Haglund deformity without major modifications in the alignment. Methods: A total of 20 WBCT scans of patients with IAT were included. The WBCT images were run through the Foot & Ankle module of Disior's BonelogicTM software, creating a 3D virtual model. With this 3D model built into this software, 20 virtual Zadeck osteotomies standardized with a 10 mm resection wedge were performed using the virtual osteotomy module of Bonelogic®. The Calcaneal Inclination angle (sagittal view)7; Talocalcaneal angle (sagittal view)8; Talocalcaneal angle (axial view)8; Saltzman angle (45 degrees view)9; Saltzman angle (20 degrees view)9; Hindfoot moment arm angle;10 Hindfoot angle10; Fowler Philips angle11 and the calcaneal length7 were measured before and after the virtual osteotomy. These results were compared and statistically analyzed. Results: A virtual Zadek osteotomy was realized in 20 WBCT from patients with an insertional Achilles tendinopathy. Most of the patients were female, and the mean age was 55 years. There were significant statistical differences in the average of the calcaneal length (79 mm to 73 mm), Fowler Philips angle (57º to 43º), calcaneal pitch ( 24º to 20º ), sagittal talocalcaneal angle (55º to 47º ), and the hindfoot moment arm angle (20 º to 21,8º). The axial talocalcaneal angle, Saltzman view 45 º and 20 º, and Hindfoot moment arm showed subtle modifications. Conclusion: The virtual analysis of Zadek's osteotomy decreased the Fowler Philips angle, shortened the calcaneus, and modified the alignment in the sagittal view. It suggests that Zadek's procedure reduces the bone impingement with Achilles and the Achilles push. The effect of this osteotomy in Hindfoot Alignment was subtle, modifying only the sagittal plane

Acute Deltoid Injury in Ankle Fractures: A Biomechanical Analysis of Different Repair Constructs

Category: Trauma; Ankle Introduction/Purpose: The importance of the deltoid ligament in the congruency of the tibiotalar joint is well known. The current trend is to repair it in cases of acute injuries in the context of ankle fractures, however, there is no information on how it should be reconstructed. The objective of this study was to compare different deltoid ligament repair types in an ankle fracture cadaveric model. Methods: 16 cadaveric foot-ankle-distal tibia specimens were used to conduct the study. All samples were prepared as a supination external rotation ankle fracture model. An axial load and cyclic axial rotations were applied on every specimen using a specifically designed frame. This test was performed without deltoid injury, with deltoid injury and finally with the ligament reconstructed. The reconstruction was performed in 4 different ways (anterior, posterior, middle, combined) using 4 specimens per group. Medial clear space (MCS) was measured for each condition on simulated weight-bearing and gravity stress radiographs. Reflective markers were utilized in tibia and talus, registering through a motion analysis system the kinematics, to record the tibiotalar uncoupling. Statistical analysis was performed using the SPSS software. Results: In all cases, the MCS increased significantly on gravity stress radiographs after damaging the deltoid ligament. There was no increase in the MCS on load radiographs. After repair, in all cases, the MCS was normalized. Kinematically, after damage the tibiotalar uncoupling increased significantly, decreasing after repair. All repairs significantly corrected the tibiotalar uncoupling, observing a significantly increased coupling effect (increased stiffness) with the combined repair. Conclusion: Our results show that deltoid repair recovers the tibiotalar coupling mechanism in an ankle fracture model. We suggest that the ideal repair should aim to repair the middle aspect of the deltoid ligament. The combined repair may lead to postoperative stiffness. Clinical studies are needed to prove these results and show clinically improved outcomes

Progressive First Metatarsal Shortening is Observed Following Allograft Interpositional Arthroplasty in Hallux Rigidus

Category: Midfoot/Forefoot; Bunion Introduction/Purpose: Interpositional arthroplasty (IPA) is a motion-preserving surgery in patients with advanced hallux rigidus. Literature displays several complications after the procedure including transfer metatarsalgia, cock-up deformity and infection. In a finite element model, shortening of the first metatarsal was associated with increased plantar pressure on lateral rays during gait. Additionally, there are reports of a positive correlation between first metatarsal shortening after hallux valgus surgery and transfer metatarsalgia of the second, third and fourth metatarsophalangeal joints. The goals of this study were to report the outcomes and complications of IPA using acellular dermal allograft (IPA-ADA) as well as study the changes in the length of the proximal phalanx of the hallux (P1) and the first metatarsal (M1) following the procedure. Methods: In this IRB-approved retrospective study, we assessed patients who underwent IPA-ADA in a single academic institute during the period 2019-2022. All patients’ demographic data, surgical details, complications, and patient-reported outcomes (PROs) were extracted. On standing conventional anteroposterior (AP) foot views, we measured the lengths of the first metatarsal (M1), the second metatarsal (M2), the proximal phalanx of the big toe (P1) and the entire length of the hallux (HX). The ratio of M1/M2 and P1/HX were calculated. The first metatarsophalangeal joint space was measured at the medial and lateral aspects of the joint on the AP view. All measurements were recorded pre-operatively, at six weeks follow-up and at the final follow-up. Descriptive statistics were performed, comparison between groups was performed using analysis of variance (ANOVA) or Kruskal Wallis test according to data normality. The Dunn-Bonferroni test was then performed for pairwise group comparisons.A p-value < 0.05 was considered significant. Results: Eleven patients were included, 9 being females (81.81%). Six were hallux rigidus Coughlin grade III (54.55%) and 5 were grade IV (45.45%). The average age was 59 years (SD±6.78) and the body mass index (BMI) was 26 (SD±4.79). At the final follow- up, there was significant shortening of the first ray in comparison to the pre-operative length evidenced by lower M1/M2 (82.63 SD±2.29 versus 75.42 SD±5.1; p=0.001) and P1/HX ratio 53.38 ± 2.29 versus 48.98 SD ± 7.92; p=0.001). Although there was no significant difference between M1/M2 at 6 weeks and at the final follow-up (p=0.716), there was a significant negative correlation between follow-up length and M1/M2 (r= -0.76, p=0.003). Follow-up was (19.95 months; range 3-39). Complications and PROs are listed in Figure 1. Conclusion: Interposition arthroplasty using dermal allograft for HR is associated with progressive shortening of the first ray at the level of the first metatarsal as well as the proximal phalanx. Although the study did show shortening of the first ray, the small sample size didn't allow for a correlation between this shortening and complications such as transfer metatarsalgia and cock-up toe deformity. The potential shortening should be considered in the selection of patients, particularly in the setting of an already short first metatarsal or when simultaneous Akin/Moberg osteotomy is planned

Integrity of the First Metatarsal Head Vascularization and Soft-Tissue Envelope Following Minimally Invasive Chevron Osteotomy for Hallux Valgus (HV) Deformity: A Micro-CT and Anatomical Assessment

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Minimally invasive surgery (MIS) Chevron-osteotomy for HV treatment offers a surgical alternative to open surgery with minimal surgical dissection and a hypothetical decreased risk for soft-tissue complications. During this procedure, there is a concern regarding the injury to the blood supply of the 1st-metatarsal-head. The objective of this study was to assess the incidence of injuries: (1) to the soft-tissue envelope around the first metatarsal head complex and, (2) to the blood supply of the first metatarsal head and also by using Micro-CT, (3) looking for safe zones close to the first metatarsal head to perform MIS Chevron osteotomy. We hypothesized that the MIS Chevron-type osteotomy procedure would preserve the soft-tissue envelope of the first-metatarsal-head complex and the blood supply of the 1st-metatarsal-head. Methods: Sixteen HV deformity cadaveric specimens were used to perform MIS Chevron-type osteotomy of the first metatarsal head. Anatomical dissection of all specimens was then performed to assess macroscopic injury to the first metatarsal head complex soft-tissue structures, including Extensor Hallucis Longus (EHL) tendon, Extensor Hallucis Brevis (EHB) tendon, Flexor Hallucis Longus (FHL) tendon, Flexor Hallucis Brevis (FHB) tendon, Abductor Hallucis tendon, Adductor Hallucis tendon, Sesamoid complex, Dorsolateral and Dorsomedial digital branches of the first toe and the Dorsomedial digital branch to the second. Macroscopic injuries were classified using a calibrated digital caliper. Any chondral damage to the first metatarsal head was quantified in mm². To assess the amount of first metatarsal head blood supply, specimens were perfused with 200 ml of a low viscosity radiopaque polymer, MV 117 (Flowtech), preoperatively, followed by Micro-CT assessment. Descriptive statistics and percentages were utilized for categorical data. Results: We did not find injuries in the EHL, EHB, FHL, Abductor-Hallucis, and Adductor-Hallucis tendons. We found a 2mm injury in the FHB tendon in one specimen. No injuries were found in the Dorsomedial and Dorsolateral nerves of the first-toe, the Dorsomedial-nerve of the second-toe, and Medial branch of the dorsomedial-nerve of the first-toe. In 3 cases, we found an injury on first-metatarsal-head (1mm) due to the passage of the K-wire and, in 1 case, due to the inadvertent passage of the drill (4.41mm). Macroscopically and using Micro-CT, we did not observe injuries in the First-Dorsal-Metatarsal-Artery (FDMA), Lateral-Dorsal-Branch of FDMA, and Plantar-Metatarsal-Artery. Micro-CT helped estimate a safe distance to finish the proximal exit of Chevron-osteotomy (25mm from the most distal point of the first metatarsal head). Conclusion: In this study, the minimally invasive Chevron osteotomy for treating HV seems to be a technically safe procedure, presenting a low rate of iatrogenic injuries with a low degree of severity. In addition, using Micro-CT promoted a better visualization of the microvasculature that nourishes the first metatarsal head. We observed that a proximal distance of 25 mm from the most distal part of the first metatarsal head could be a safe place to finalize the Chevron osteotomy, minimizing the risk of injury to the blood supply of the first metatarsal head

Semiautomatic Weight Bearing Computed Tomography Area Analysis of the Distal Tibiofibular Syndesmotic Incisura in Subtle Chronic Syndesmotic Instability

Category: Ankle; Sports Introduction/Purpose: Syndesmotic injuries and residual chronic subtle distal tibiofibular syndesmotic instability (DTFSI) are relatively common injuries, especially in athletes prone to suffering high ankle sprains. The diagnosis of subtle DTFSI remains challenging, with a high prevalence of false-negative results using conventional non-invasive clinical-radiographical diagnostic tools. The current gold standard for diagnosis, arthroscopy, is a surgical operation, which is invasive and, therefore, not ideal. Weightbearing Computed-Tomography (WBCT) has emerged as a possible dynamic non-invasive alternative diagnostic option, with proven high diagnostic accuracy for syndesmotic incisura area measurements in major DTFSI. Our study aimed to assess the capability of semiautomatic weight-bearing computed tomography (WBCT) syndesmotic incisura area in diagnosing subtle chronic syndesmotic instability. Methods: In this diagnostic case-control study, patients with suspected unilateral chronic subtle DTFSI underwent bilateral standing weight-bearing CT (WBCT) before surgical treatment. All patients had gold-standard arthroscopic assessment for DTFSI, introducing a 3mm diameter arthroscopic sphere into the syndesmotic incisura for diagnosis. Bilateral syndesmotic incisura areas were measured 10mm proximally to the apex of the distal tibia articular dome using a semiautomatic measurement algorithm. Two tangent lines marked the anterior and posterior borders of the syndesmotic incisura to the anterior and posterior edges of the distal tibia and fibula. Once borders were marked, the incisura area was automatically calculated by the software based on a Hounsfield units (HU) contrast algorithm. A HU threshold of 200HU was utilized. Measurements were done independently by two fellowship-trained readers. Comparisons between injured and control ankles were made using Student T-test or Wilcoxon, according to normality. Measurements' reliability was assessed with the Intraclass Correlation Coefficient (ICC). Results: From an initial sample of 32 patients, 20 patients (12 female) with arthroscopically confirmed DTFSI (11 right sides) with a mean age of 31.7 years (range 18 to 55 years) and a mean BMI of 30.35kg/m² (SD +/-8.29 kg/m²) were included in the study. All patients had a history of an old ankle sprain 6 to 182 months before the assessment, and athletic lesions were reported in 53% of the population. ICCs were above 0.98 for both intra and interobserver reliability. The average syndesmotic area was 96.91mm 2 (SD +/-27.9mm 2 ) in injured ankles compared to 84.61mm 2 (SD +/-26.9 mm 2 ) in uninjured ankles. The difference between injured and non-injured tibiofibular areas was 12.31mm 2 (95%CI: 9.04-15.58mm 2 ), which was shown statistically significant (p < 0.001; effect size: 1.43). Conclusion: In this case-control study, we assessed the accuracy of semiautomatic WBCT syndesmotic incisura area measurements in diagnosing subtle chronic DTFSI. We found an increased syndesmotic area in injured ankles that reached statistical significance. Due to the minimal differences between injured and uninjured contralateral ankles, larger cohorts would likely solidify this study's findings further. The use of external rotation stress, volumetric assessment, distance, and coverage maps could increase the diagnostic accuracy in DTFSI. However, automatic area measurements have a higher overall reproducibility and applicability in the clinical setting, which could help providers make therapeutic decisions