MRI of the distal tibiofibular joint

Nonoperative Management of High Ankle Sprains: A Case Series With ≥18-Year Follow-up

BACKGROUND

High ankle sprains are common athletic injuries and can be associated with long-term sequelae. Regardless of operative or nonoperative treatment, there is a paucity of data in the literature about the long-term outcomes of high ankle sprains.

HYPOTHESIS

Nonoperative treatment of high ankle sprains utilizing a standardized protocol will result in good long-term outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who experienced a high ankle sprain without radiographic diastasis of the syndesmosis were identified from a previous study database and contacted for long-term follow-up. All patients were high school or National Collegiate Athletic Association Division IA athletes at initial injury and were treated nonoperatively with the same standardized protocol. Patients completed a questionnaire that included documentation of any interim ankle injuries, 2 different patient-reported outcome scores, and ankle radiographs to conduct Kellgren-Lawrence scoring for ankle osteoarthritis.

RESULTS

In total, 76 cases in 74 patients were identified in the database. A total of 40 patients were successfully contacted, and 31 patients (24 collegiate and 7 high school athletes) with 33 high ankle sprains completed the survey (31/40; 77.5%). The mean age at follow-up was 45 years (range, 34-50 years), with a mean time from injury to follow-up of 25 years. Overall, 93.5% (n = 29) of the respondents were male, and 42% (n = 13) of the respondents reported an ipsilateral ankle injury since their initial injury, with 16% (n = 5) having ankle or Achilles surgery. The mean Patient-Reported Outcomes Measurement Information System-10 score was 53.4 (SD, 8.3; range, 37.4-67.7), PROMIS median (IQR), 54.1 (39.9, 68.3), and the mean Self-reported Foot and Ankle Score score was 42.7 (SD, 5.86). Follow-up ankle radiographs were obtained in 11 (35%) of the respondents; 27% had Kellgren-Lawrence grade >2 osteoarthritis, and 36% had signs of heterotopic ossification on imaging. The mean tibiofibular clear space was 4.5 mm, and the mean tibiofibular overlap was 7.15 mm, with 27% of patients demonstrating some tibiotalar narrowing.

CONCLUSION

At long-term follow-up, nonoperative management of high ankle sprains without diastasis on imaging was associated with acceptable patient-reported functional outcomes and low rates of subsequent ankle injuries. There was a high incidence of arthritis, but most cases were not clinically significant. This case series shows the natural history of nonoperatively treated high ankle sprains and may serve as a comparison for different management techniques in the future.

The morphometry of distal tibia and posterior malleolus and its clinical implications in total ankle prosthesis

PURPOSE

The aim of this study is to reveal the morphometry of the distal tibia and posterior malleolus and to generate morphometric reference data for the tibial component of total ankle prosthesis.

METHODS

This study was performed on 121 human dry tibiae (47 right, 74 left). The morphometric measurements of distal tibial structures, tibial length and the distance between the medial and posterior malleolus were measured in this study. Measurements on 44 tibiae were repeated three times and averaged for minimizing intra-observer error.

RESULTS

The tibial length was found 34.19 ± 2.31 cm. Mean values of width of fibular notch at tibial plafond and 10 mm proximal to the tibial plafond were 25.71 ± 2.44 mm and 17.81 ± 2.46 mm, respectively. Mean depth of fibular notch at tibial plafond and 10 mm proximal to the tibial plafond were 3.60 ± 1.04 mm and 3.37 ± 1.24 mm, respectively. Mean height of fibular notch was found 48.21 ± 10.51 mm. Mean width and height of medial malleolus were 25.08 ± 2.13 mm and 14.73 ± 1.85 mm, respectively. Mean width and length of tibial plafond were 27.71 ± 2.74 mm and 26.96 ± 2.62 mm, respectively. Mean values of width and height of posterior malleolus were measured 21.41 ± 3.26 mm and 6.74 ± 1.56 mm, respectively. Mean distance between medial and posterior malleolus was found 37.17 ± 3.53 mm. Mean width and depth of malleolar groove were 10.26 ± 1.84 mm and 1.73 ± 0.75 mm, respectively. The mean intra-class correlation values were found between the 0.959 and 0.999.

CONCLUSIONS

Knowing the distal tibial morphometry is crucial for designing convenient ankle replacement implants for Turkish population. To our knowledge, this study is the first in the literature that identifies posterior malleolar morphometry on dry tibiae. We believe that this study will make a significant contribution to the literature about distal tibial morphometry and especially the posterior malleolus and the data of our study can be used for designing total ankle prosthesis in Turkish population.

A quantitative assessment of the anterior tibiofibular gap with and without weight-bearing in healthy adults: An ultrasound-based study

BACKGROUND

Difficulties in the accurate evaluation of tibiofibular clear space in plain radiographs are diagnostic problems in the clinical setting of syndesmosis injury. This study aimed to quantify the anterior tibiofibular gap (ATFG) with weight-bearing using ultrasonography.

METHODS

In total, 32 healthy adults (16 men and 16 women) with 64 feet participated in this cross-sectional study. The ATFG was measured along the anterior inferior tibiofibular ligament for a US assessment conducted in both sitting and standing postures. The ankle joint was set on the tilt table at four different angles as follows: plantar flexion, 20° (P20); neutral position (N); dorsiflexion, 20° (D20); and dorsiflexion, 20°+ external rotation, 30° (D20ER30). The ankle joint position, sex, and side-to-side values were compared with and without weight-bearing.

RESULTS

Under all ankle angle conditions, the ATFG was wider in the standing posture than in the sitting posture (p < 0.001). In both sitting and standing postures, the ATFG widened with increasing dorsiflexion angle, eventually reaching a maximum at D20ER30. The widening ratio (D20ER30/N) in the standing posture was higher in women than in men (p < 0.05). No statistical differences were identified side-to-side differences in the ATFG.

CONCLUSIONS

Ultrasound measurements for identifying unphysiological increases in ATFG with weight bearing, especially given the side-to-side differences, may provide a means for quantitatively assessing syndesmosis injury in a clinical setting. Further research is warranted to clarify direct attribution as a clinical diagnostic utility of the ATFG measurements for syndesmosis injuries.

The distal tibiofibular joint effusion may be a reliable index for diagnosing the distal tibiofibular syndesmosis instability in ankle

PURPOSE

To analyze the accuracy of MRI in diagnosis of distal tibiofibular syndesmosis instability (DTSI) and construct new diagnostic parameters.

MATERIALS AND METHODS

This retrospective study evaluated 212 patients with history of ankle sprains and 3 T MRI and received a final diagnosis of distal tibiofibular syndesmosis instability by ankle arthroscopic surgery from October 2017 and December 2021. We compared the accuracy of syndesmotic injury, qualitative index of distal tibiofibular joint effusion (DTJE), and quantitative index of distal tibiofibular joint effusion (DTJE) in diagnosing distal tibiofibular syndesmosis instability. The criteria for syndesmotic injury were consistent with previous literature, and DTJE was grouped according to the pre-experimental results.

RESULTS

A total of 212 patients (mean age, 35.64 ± 11.79, 74 female and 138 male) were included. Independent predictive MRI features included syndesmotic injury, qualitative index of distal tibiofibular joint effusion, and quantitative index of DTJE including the height, projected area of equal-point method, and projected area of incremental-value method. The quantitative index of DTJE showed a higher area under the receiver operating characteristic curve (0.805/0.803/0.804/0.811/0.817/0.805 > 0.8, P < 0.05; in comparison with all other method). The height measurement method was simpler and easier to operate, that could be gotten only by measuring the DTJE distance of a MRI independent layer, and the cut-off value of the effusion height was 8.00 mm and the Youden index (0.56) was the best.

CONCLUSIONS

Our research translated a complicated string of MRI multi-dimensional spatial measurements into a simple measuring process, and established the significance of quantifying DTJE in the diagnosis of DTSI. We found that the 8-mm height of DTJE was a more specific indicator for DTSI and could serve as a novel MRI diagnostic cutoff in clinical practice.

Standardized analysis of syndesmosis stability in ankle trauma with an innovative syndesmosis-test-tool: a biomechanical study

When treating ankle fractures, the question of syndesmosis complex involvement often arises. So far, there is no standardized method to reliably detect syndesmosis injuries in the surgical treatment of ankle fractures. For this reason, an intraoperative syndesmosis-test-tool (STT) was developed and compared to the recommended and established hook-test (HT). Tests were performed on cadaveric lower legs (n = 20) and the diastasis was visualized by 3D camera. Tests were performed at 50, 80, and 100 N in native conditions and four instability levels. Instability was induced from anterior to posterior and the reverse on the opposite side. The impact on diastasis regarding the direction, the force level, the instability level, and the device used was checked using a general linear model for repeated measurement. The direction of the induced instability showed no influence on the diastasis during the stability tests. The diastasis measured with the STT increased from 0.5 to 3.0 mm depending on the instability, while the range was lower with the HT (1.1 to 2.3 mm). The results showed that the differentiation between the instability levels was statistically significantly better for the developed STT. The last level of maximum instability was significantly better differentiable with the STT compared to the HT. An average visualizable diastasis of more than 2 mm could only be achieved at maximum instability. In conclusion, the newly developed STT was superior to the commonly used HT to detect instability.

Standing on single foot-binding test yields satisfactory results as a novel method for the diagnosis of distal tibiofibular syndesmosis instability: a prospective, cross-sectional diagnostic-accuracy study

BACKGROUND

Non-invasive diagnosis of distal tibiofibular syndesmosis instability (DTSI) was a great challenge to clinicians. We designed a new method, the Standing on single foot-Binding test, and investigated the accuracy of the test in the diagnosis of distal tibiofibular syndesmosis instability in adults with a history of ankle injury.

METHODS

85 participants with ankle injury were subjected to the Standing on single foot-Binding test, MRI and palpation to detect the distal tibiofibular syndesmosis instability (DTSI) and the findings were compared with ankle arthroscopic results. Both participants and arthroscopist were blind to the predicted results of the clinical tests. Sensitivity, specificity, PPV, NPV, LR+, LR - and their 95% CIs were calculated for each of the clinical tests as well as for the positive clinical diagnosis.

RESULTS

The Standing on single foot-Binding test (SOSF-B test) outperformed MRI and palpation, in terms of sensitivity (87.5%/84.38%), specificity (86.79%/86.79%), PPV (80%/79.41%), NPV (92%/91.2%), LR+ (6.625/6.39), LR- (0.14/0.18) and diagnostic accuracy (87.06/85.88), among others, in the diagnosis of distal tibiofibular syndesmosis instability (DTSI). The diagnostic performance of 20° SOSF-B test was virtually identical to that of 0° SOSF-B test. According to the prevalence (28.7%) of DTSI and LR of four tests, the post-test probability could be used in clinical practice for the prediction of DTSI.

CONCLUSION

This prospective and double-blind diagnostic test showed that the SOSF-B test is clinically feasible for the diagnosis of distal tibiofibular syndesmosis instability (DTSI), and new diagnostic tools for rapid screening of distal tibiofibular syndesmosis instability (DTSI).

LEVEL OF EVIDENCE

II.

Syndesmosis dislocation and ankle ligament stress in the posterior malleolus fracture fixated - "in vitro analysis"

PURPOSE

The objectives of this study were to compare syndesmosis dislocation and ankle ligament stress after the fixation of the posterior malleolus fracture (PMF) with four different techniques by Finite Element Analysis (FEM).

METHODS

Four internal fixation techniques used for fixation of PMF were assessed by FEM: posterior one-third tubular 3.5 mm buttress plate (PP) with one screw (PP 1 screw), PP with two screws (PP 2 screws), two cannulated 3.5 mm lag screws in the anteroposterior (AP) direction (AP lag screws), and two posteroanterior (PA) cannulated 3.5 mm lag screws (PA lag screws). PMF with 30% fragment size was simulated through computational processing reconstructed from computed tomography (CT). The simulated loads of 700 N and 1200 N were applied to the proximal tibial end. The FEM evaluated the syndesmosis dislocation (mm) and stress values of the posterior tibiofibular ligament (PTFL) (in Kpa) and deltoid ligament (in Kpa) in the four mentioned subgroups.

RESULTS

We found that with a load of 700 N, syndesmosis dislocation varied from 6.5 to 7.9 mm, being the lowest and greatest for PA lag screw and PP 1 screw, respectively. In all groups was observed a greater dislocation in the syndesmosis at 1200 N of load. We observed that the stress values on the PTFL were lower for AP lag screws and PP 2 screws with 700 N and 1200 N, respectively. For both loads, PP 1 screw presented the greatest stress. Regarding the stress in the deltoid ligament, the AP lag screws presented the lowest stress for 700 N and PP 1 screw for 1200 N. For all fixation techniques, the syndesmosis displacement and ligament stresses were higher when 1200 N were imposed.

CONCLUSION

This study demonstrated that PMF fixed with lag screws presents greater stability in the distal tibiofibular syndesmosis and higher joint loadings promoted greater displacement and ligaments stress, regardless of the fixation technique. Besides, lower stress in the syndesmosis is accompanied by a greater load on the deltoid ligament.

Technical note: Intraoperative ultrasound measurement for evaluating the stability of the inferior tibiofibular joint in patients with ankle fractures

OBJECTIVES

Injury to the tibiofibular syndesmosis is a common complication of ankle fractures. Currently, it is challenging to determine the stability of the tibiofibular joint caused by ankle fractures during surgery. This study aims to establish a standardized method for dynamically evaluating the stability of the inferior tibiofibular joint under intraoperative ultrasound and assess its utility in surgery, thereby assisting in determining the necessity for fixation of the inferior tibiofibular joint after fracture reduction and fixation.

METHODS

The stability of the inferior tibiofibular joint was assessed using an intraoperative ultrasonic external rotation stress test, with a torque set at 7.2 N·m. The measured parameters included the width of the inferior tibiofibular space in neutral (N) and external rotation (E) positions, stretch ratio (E/N), and injured/healthy side stretch ratio (I/H). Patients with Weber B or C type ankle fractures were selected as participants.

RESULTS

For the case with Weber C fracture, the N measurement was 4.22 mm after fracture fixation, while E measured 5.77 mm and E/N ratio was 1.37, which were larger than those on the healthy side (N: 4.17, E: 4.50, E/N:1.08), with an I/H ratio of 1.27. Intraoperative X-ray revealed instability of the inferior tibiofibular joint. After inserting a tibiofibular screw, the N measurement was 4.20 mm, while the E measurement recorded 4.32 mm, resulting in an E/N ratio of 1.03 and an I/H ratio of 0.95, indicating improved joint stability. For the Weber B fracture case, the N measurement was 3.55 mm after fracture fixation, while E measured 3.98 mm and the E/N ratio was 1.12, slightly lower than those on the healthy side (N: 3.94, E: 4.47, E/N: 1.13), with an I/H ratio of 0.99. The intraoperative X-ray revealed stability of the inferior tibiofibular joint. Therefore, no further fixation was performed on it.

CONCLUSION

Standardized intraoperative ultrasound stress test allows for real-time, dynamic assessment of the stability of the inferior tibiofibular joint after ankle fracture reduction and fixation, which can help guide the fixation of the inferior tibiofibular joint, thereby reducing the risk of postoperative traumatic arthritis.

Ankle Sprains in Athletes: Current Epidemiological, Clinical and Imaging Trends

Purpose

Ankle injuries are frequent sports injuries. Despite optimizing treatment strategies during recent years, the percentage of chronification following an ankle sprain remains high. The purpose of this review article is, to highlight current epidemiological, clinical and novel advanced cross-sectional imaging trends that may help to evaluate ankle sprain injuries.

Methods

Systematic PubMed literature research. Identification and review of studies (i) analyzing and describing ankle sprain and (ii) focusing on advanced cross-sectional imaging techniques at the ankle.

Results

The ankle is one of the most frequently injured body parts in sports. During the COVID-19 pandemic, there was a change in sporting behavior and sports injuries. Ankle sprains account for about 16-40% of the sports-related injuries. Novel cross-sectional imaging techniques, including Compressed Sensing MRI, 3D MRI, ankle MRI with traction or plantarflexion-supination, quantitative MRI, CT-like MRI, CT arthrography, weight-bearing cone beam CT, dual-energy CT, photon-counting CT, and projection-based metal artifact reduction CT may be introduced for detection and evaluation of specific pathologies after ankle injury. While simple ankle sprains are generally treated conservatively, unstable syndesmotic injuries may undergo stabilization using suture-button-fixation. Minced cartilage implantation is a novel cartilage repair technique for osteochondral defects at the ankle.

Conclusion

Applications and advantages of different cross-sectional imaging techniques at the ankle are highlighted. In a personalized approach, optimal imaging techniques may be chosen that best detect and delineate structural ankle injuries in athletes.

Comparison of the diagnostic value of measurements of transverse syndesmotic interval and 'lambda sign' in distinguishing latent syndesmotic diastasis in chronic lateral ankle instability: a cross-sectional study of 188 cases

INTRODUCTION

Chronic lateral ankle instability (CLAI) could accompany with latent syndesmotic diastasis (LSD), which is difficult to distinguish before surgery. Tibiofibular interval width and extravasation of joint fluid ('lambda sign') on MRI are widely used in the diagnosis of syndesmotic injury, but the reliability of these methods in distinguishing the associated LSD in CLAI was rarely studied. Our objective was to compare the diagnostic value of the measurement of the transverse tibiofibular interval and 'lambda sign' on MRI in distinguishing LSD in CLAI and to investigate the radiological predictor that best matched the intraoperatively measured syndesmotic width.

METHODS

138 CLAI patients undergoing arthroscopy in our institute from March 2017 to June 2020 were enrolled (CLAI group). Anterior space width (ASW) and posterior space width (PSW) at 10 mm layer above tibial articular and fluid height above tibial articular surface (FH) were measured on preoperative MRI. The same parameters were measured on MRI of 50 healthy volunteers as control group. At arthroscopy, syndesmotic width was measured and the patients were divided into arthroscopic widening (AW) and arthroscopic normal (AN) subgroup taking 2 mm as critical value. The CLAI group was compared with the control group to explore the interval changes related to CLAI. The AW and AN subgroups were compared to explore the potential diagnostic indicators and reference values for the LSD.

RESULTS

All parameters showed significant difference between CLAI group and control group (p < 0.05), but only PSW (p = 0.004) showed significant difference between AW and AN subgroups other than FH (p = 0.461). Only PSW was involved in formula of multiple-factor analysis (p = 0.005; OR, 1.819; 95%CI, 1.196-2.767). ROC analysis showed critical value of PSW was 3.8 mm (sensitivity, 66%; specificity, 66%; accuracy, 66.7%), while accuracy of lambda sign was 41.3%.

CONCLUSIONS

Transverse tibiofibular interval measurements were more reliable than the 'lambda sign' in distinguishing associated LSD in CLAI patients. The PSW ≥ 3.8 mm could be a predictor of syndesmotic diastasis.

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

BACKGROUND

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.

PURPOSE

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.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 2.

METHODS

Between September 2018 and April 2021, this prospective study consecutively included adults visiting the foot and ankle outpatient clinic with a positive orthopaedic 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 did 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 a 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. The ideal cutoff point for the first CT scan with a neutral position was 0.7 mm in the rotational measurement a, with a sensitivity of 25% and specificity of 97%.

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.

Which test is the best? An updated literature review of imaging modalities for acute ankle diastasis injuries

Ankle diastasis injuries, or ankle syndesmotic injuries, are common among athletes who usually experience a traumatic injury to the ankle. Long‐term complications are avoidable when these injuries are diagnosed promptly and accurately treated. Whilst ankle arthroscopy remains the gold standard diagnostic modality for ankle diastasis injuries, imaging modalities are still widely utilised due to the treatment having greater accessibility, being less invasive and the most cost effective. There are various imaging modalities used to diagnose diastasis injuries, varying in levels of specificity and sensitivity. These observation methods include; X‐ray, computed tomography (CT), magnetic resonance imaging (MRI) and ankle arthroscopy. This article uncovers common criteria and parameters to diagnose diastasis injuries through the implementation of different imaging modalities. The conclusions addressed within this article are deduced from a total of 338 articles being screened with only 43 articles being selected for the purposes of this examination. Across most articles, it was concluded that that plain X‐ray should be used in the first instance due to its wide availability, quick processing time, and low cost. CT is the next recommended investigation due to its increased sensitivity and specificity, ability to show the positional relationship of the distal tibiofibular syndesmosis, and reliability in detecting minor diastasis injuries. MRI is recommended when ankle diastasis injuries are suspected, but not diagnosed on previous imaging modalities. It has the highest sensitivity and specificity compared to X‐ray and CT.

Syndesmotic instability can be assessed by measuring the distance between the tibia and the fibula using an ultrasound without stress: a cadaver study

Background

Ultrasound examinations for syndesmosis injury might be useful for the quantitative evaluation of syndesmotic instability. The purpose of this study was to evaluate the efficacy of ultrasound assessment by measuring the tibiofibular distance of syndesmosis injuries in various ligament-injured models and stress load conditions.

Methods

Five normal ankles from Thiel-embalmed cadavers were used. Ultrasound assessment was performed by placing a probe in parallel with the ligament running just above the anterior inferior tibiofibular ligament (AITFL). The distance between the anterior border of the tibia and the fibula was measured in the intact condition. Next, Bassett’s ligament was cut arthroscopically to reduce damage to soft tissues as much as possible and measurement was performed in the same way. After that, the AITFL, interosseous membrane (IOM), deltoid ligament, and posterior inferior tibiofibular ligament (PITFL) were macroscopically cut and measured in that order. Ankle positions were without stress (natural plantar flexion without applying stress to the ankle joint), dorsiflexion stress, inversion stress, and external rotation stress. All stress to the ankle joint was carried out manually to the maximum extent.

Results

As with the without-stress condition, significant increases in tibiofibular distances after AITFL dissection were seen compared with the intact state under all stress conditions (intact: 4.9 ± 1.0 mm without stress, 5.6 ± 1.2 mm with dorsiflexion, 5.9 ± 1.0 mm with inversion, and 6.7 ± 1.3 mm with external rotation; AITFL dissection: 6.7 ± 1.5 mm without stress, 7.3 ± 1.2 mm with dorsiflexion, 7.5 ± 1.4 mm with inversion, and 8.7 ± 1.6 mm with external rotation). AITFL dissection with external rotation stress significantly increased the tibiofibular distance compared to without stress.

Conclusion

Changes in tibiofibular distance with the severity of syndesmosis injury were measured by ultrasound using cadavers. No significant change was seen with Bassett’s ligament injury, but tibiofibular distance increased significantly with injuries of equal to or greater severity than AITFL injury. Results were similar not only for external rotation stress, but also for dorsiflexion stress and inversion stress, and even in unloaded states, significant tibiofibular widening was confirmed with injuries of equal to or greater severity than AITFL injury.

3-T MRI of the Ankle Tendons and Ligaments

Ankle sprain is the most common injury in athletic populations. Ligament and tendon pathologies of the ankle are common, ranging from traumatic injuries to degeneration leading to chronic pain and acquired foot deformities. MRI is the imaging modality of choice to evaluate tendon and ligament pathology of the ankle, specifically derangements of tendons and ligaments. 3-T MRI offers improved imaging characteristics relative to 1.5-T MRI, allowing for better delineation of anatomic detail and pathology. This article provides a review of the anatomy and common pathologies of the ankle ligaments and tendons using high-resolution 3-T MRI.

Comparative CT with stress manoeuvres for diagnosing distal isolated tibiofibular syndesmotic injury in acute ankle sprain: a protocol for an accuracy- test prospective study

INTRODUCTION

Although several imaging options are available for diagnosing syndesmotic injury, a fundamental question that guides treatment remains unanswered. Syndesmotic instability is still challenging to diagnose correctly, and syndesmotic disruption and true syndesmotic instability should be differentiated. Currently, imaging tests quickly diagnose severe syndesmotic instability but have difficulty in diagnosing mild and moderate cases. This study aims to investigate which strategy among an existing CT index test and two new add-on CT index tests with stress manoeuvres more accurately diagnoses syndesmotic instability. The secondary objective is to investigate the participants' disability outcomes by applying the Foot and Ankle Ability Measure questionnaire.

METHODS AND ANALYSES

This study of a diagnostic accuracy test will consecutively select individuals older than 18 years with a clinical diagnosis of a suspected acute syndesmotic injury. Three strategies of the CT index test (one in the neutral position and two with stress) will examine the accuracy using MRI as the reference standard. The external rotation and dorsiflexion of the ankle will guide the stress manoeuvres. A comparison of measurements between the injured syndesmosis and the uninjured contralateral side of the same individual will investigate the syndesmotic instability, by evaluating the rotational and translational relationships between the fibula and tibia. Sensitivity, specificity, area under the receiver operating characteristic curve and likelihood analyses will compare the diagnostic accuracies of the strategies.

ETHICS AND DISSEMINATION

The Internal Review Board and the Einstein Ethics Committee approved this study (registered number 62100016.5.0000.0071). All participants will receive an oral description of the study's aim, and the choice to participate will be free and voluntary. Participants will be enrolled after they sign the written informed consent form, including the terms of confidentiality. The results will be presented at national and international conferences and published in peer-reviewed journals and social media.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT04095598; preresults).