Bilateral External Rotation Torque CT Remains Reliable in Syndesmotic Assessment Despite Lateral Ligament Injury,but Reveals Increased Tibiotalar Rotational Instability

Abstract

Background:

Understanding syndesmotic injury in conjunction with lateral ligament disruption is essential for accurate diagnosis and treatment. Although the influence of deltoid ligament injury on syndesmotic evaluation during bilateral external torque computed tomography (BET-CT) has been examined, the effect of concurrent lateral ligament lesion remains unclear and is rarely examined in the literature. This leads to the question of whether a lateral ligament lesion influences the previously established measurement parameters of syndesmosis instability in BET-CT and whether it results in a quantifiable increase in tibiotalar instability.

Methods:

Seven paired cadaveric lower limbs (n = 14; mean age 78.6 years) with pre-existing iatrogenic syndesmotic transection underwent sequential lateral ligament sectioning: anterior talofibular (ATFL), calcaneofibular (CFL), and posterior talofibular ligaments (PTFL). BET-CT imaging was performed under applied external rotation torques of 0, 2.5, 5.0, and 7.5 Nm. Outcome measurements included the anterior tibiofibular distance, tibiofibular clear space, posterior tibiofibular distance, medial tibiotalar gutter angle, and lateral fibulotalar gutter angle for each ligament condition and torque level.

Results:

The anterior tibiofibular distance remained stable despite progressive lateral ligament dissection and increasing torque (P > .05). Tibiofibular clear space and posterior distance measurements showed inconsistent trends and did not reach statistical significance. In contrast, the medial tibiotalar gutter angle increased significantly from 22.9° in isolated syndesmotic injury to 27.6° (±6.3°) following complete disruption of the lateral complex (P < .001).

Conclusion:

Concurrent lateral ligament injury does not impair the assessment of syndesmotic widening in BET-CT, as tibiofibular alignment remains preserved. However, disruption of the lateral complex exacerbates rotational tibiotalar instability.

Clinical Relevance:

In this cadaveric model, BET-CT remains reliable for assessing syndesmotic lesions even in the presence of lateral ligament injury. However, the increase in rotational tibiotalar instability with combined injuries highlights the need for comprehensive evaluation of ankle ligament injuries, pending clinical validation.

Keywords

syndesmotic instability external torque lateral ligaments bilateral external torque CT

Introduction

Syndesmotic injuries, whether isolated or in combination with fractures or injuries to other ligaments, represent a diagnostic and therapeutic challenge because of their complex and variable biomechanics. The syndesmotic complex, comprising the anterior tibiofibular ligament (AITFL), the interosseous ligament (IOL), and the posterior interosseous ligament (PITFL), plays a crucial role in maintaining distal tibiofibular alignment and ankle stability, with each structure contributing uniquely to restraint and load distribution.^1,2 Although the biomechanical contributions of these components have been extensively studied, most investigations have focused on syndesmotic injuries, with or without deltoid ligament disruption as well as the occurrence of its combination.^1
-12 In contrast, the role of the lateral ligament complex, comprising the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL), on syndesmotic stability or vice versa remains less well defined, even though frequently associated.^13,14

Bilateral external torque computed tomography (BET-CT) is a substantially less invasive approach compared with arthroscopy for detecting subtle syndesmotic instability.^4,15 In cadaveric models with sequential syndesmotic ligament sectioning, BET-CT demonstrated greater sensitivity and comparable specificity to the arthroscopic lateral hook test.⁴ During BET-CT, external rotation of the foot induces lateral rotation of the talus and corresponding lateral displacement of the fibula. However, when the lateral fibular ligaments are also injured—reported in up to 52% of syndesmotic injuries—this talus-fibula coupling may be diminished, potentially reducing measurable tibiofibular separation and yielding falsely low BET-CT values.^13,14 Our hypothesis was, therefore, that concomitant lateral ligament injury would decrease tibiofibular widening and increase tibiotalar rotational instability. The aims of this study were to (1) assess tibiofibular separation following sequential dissection of ATFL, CFL, and PTFL and (2) quantify tibiotalar rotational instability.

Methods

This investigation was approved by the ethical cantonal committee (BASEC-Nr. 2021-02179) and the internal responsible investigational review board.

Fourteen lower limbs (7 pairs; mean age 78.6 years, range 67-92) were used. None had a history of ankle surgery. The lower legs were rigidly fixed to a wooden board from anterior to posterior through the tibiae. During CT acquisition, specimens were mounted in the external torque device (Figure 1). BET-CT scans (NAEOTOM Alpha [Siemens Healthineers], 0.8-mm slice thickness) were obtained bilaterally in neutral position and under external rotation torques of 0.0, 2.5, 5.0, and 7.5 Nm at baseline and after each sequential dissection step. The CT setup was validated in prior studies.^4,15

Figure 1.

The figure shows the cadaveric lower leg pair mounted in the external rotation device. Using this setup, an external rotation torque could be applied on the CT scanner table.

In addition to previously set injury types of the syndesmosis the lateral ligament complex was exposed and sequentially transected in this study. Syndesmotic lesions were previously set according to the most common mechanisms for syndesmotic instability: on one side a lesion to the AITFL, IOL, and PITFL were performed (supination-external rotation pattern), whereas on the contralateral side the AITFL, IOL, and deltoid ligament were transected (pronation-external rotation pattern).

The lateral ligament complex was then exposed through distal extension of the existing lateral approach. Sequential sectioning of the (1) ATFL, (2) CFL, and (3) PTFL was performed under direct visualization (Figure 2). BET-CT external rotation testing was repeated after each ligament condition.

The assessment of the tibiofibular movement was done with the anterior distance (AD), tibiofibular clear space (TCS), and posterior distance (PD) as previously described (Figure 3).^4,15 The BET-CT rotational assessment had previously been applied in the context of sequential syndesmotic ligament lesions, where its reliability for detecting syndesmotic instability was demonstrated especially for the AD value. Consequently, the present analysis focused exclusively on the newly created experimental conditions resulting from the sequential dissection of the lateral ligament complex.

For the quantification of the tibiotalar instability, the medial tibiotalar gutter angle (MGA) and lateral fibulotalar gutter angle (LGA) were invented and assessed to evaluate tibiotalar rotational stability. Measurements were independently performed by 2 readers (PF and LC) to assess its reproducibility. Because these measurement parameters are described for the first time, they were additionally evaluated on CT scans obtained in the condition of intact ligaments as well as sequential sectioning of the syndesmosis. These data sets originated from a previous study in which the syndesmotic ligaments were subsequently sectioned in a sequential manner.⁴

Figure 2.

Depicted are the lesion types included in the analysis. Initial state with syndesmotic dissection of either AITFL/IOL/PITFL or AITFL/IOL/DL. Sequences 1 to 3 demonstrate a lesion on the ATFL, CFL, and PTFL. AITFL, anterior tibiofibular ligament; ATFL, anterior talofibular ligament; CFL, calcaneofibular ligament; DL, deltoid ligament; IOL, interosseous ligament; PITFL, posterior interosseous ligament; PTFL, posterior talofibular ligament.

Figure 3.

Images a-d represent different planes obtained from the CT scan. a and b are axial scans depicting the corresponding levels indicated in pictures c and d. c shows the sagittal view, whereas d shows the coronal view. The reference level in a was defined as 1 cm proximal to the joint space. Panel b was acquired below the joint line at a level where the talar shoulder as well as the medial and lateral malleoli are clearly visible.

Statistics

The Kolmogorov-Smirnov test was used to test the data for a normal distribution. Data are reported as mean ± SD unless otherwise indicated. Difference for metric data was calculated using T-testing for normal distributed data or Friedman Testing for paired, non-normally distributed data. Significance was set at P <.05. Interrater correlation was analyzed via the interclass correlation testing. An a priori sample size calculation indicated that 57 samples rated by both raters would be sufficient to estimate the intraclass correlation coefficient (ICC) with a 95% CI of ±0.05, assuming a true ICC of 0.90. To ensure robust estimation, we included 80 samples. Analyses were performed using IBM SPSS Statistics (IBM Corporation). No single primary outcome was prespecified; the 2 study aims (tibiofibular separation and tibiotalar rotational instability) were co-equal.

Results

In the first part of the study (1) an increasing external torque had a consistent effect on AD, with a nonsignificant increase with each additional 2.5 Nm, regardless of the ligament condition. TCS showed a minimal or absent torque-related increase, whereas PD slightly decreased with higher torque. None of these changes reached constant statistical significance. All measurements are summarized in Table 1.

Table 1.

Absolute Values of Distances Based on Lateral Ligament Lesions and External Rotation Torque.

	Isolated Syndesmotic Lesion	ATFL	ATFL + CFL	ATFL + CFL + PTFL

2.5 Nm
AD, mm	6.7 ± 2.0	7.2 ± 2.7	7.4 ±2.8	7.1 ±3.1
PD, mm	3.4 ± 1.0	2.8 ± 1.3	2.8 ± 1.3^a	3.1 ± 0.8
TCS, mm	4.5 ± 1.5	4.6 ± 2.0	4.7 ± 1.5	5.1 ± 1.9^a
5.0 Nm
AD, mm	7.4 ± 2.3	7.9 ± 2.5	7.7 ± 2.6	7.8 ± 2.8
PD, mm	3.0 ± 1.2	3.0 ± 1.0	2.3 ± 1.1^a	3.2 ±1.4
TCS, mm	5.3 ± 1.6	5.2 ± 1.8	4.9 ± 1.6	5.3 ± 1.7
7.5 Nm
AD, mm	8.3 ± 2.6	8.4 ± 2.7	8.4 ±2.6	8.5 ± 3.4
PD, mm	2.6 ± 1.1	2.6 ± 1.3	2.4 ± 1.1	2.9 ± 1.2
TCS, mm	5.2 ± 1.6	5.4 ± 2.0	5.4 ± 2.2	5.6 ± 2.0

Abbreviations: AD, anterior tibiofibular distance; ATFL, anterior talofibular ligament; CFL, calcaneofibular ligament; PD, posterior tibiofibular distance; PTFL, posterior talofibular ligament; TCS, tibiofibular clear space.

These values are statistically significant different from the others (P < .05). Friedman paired test was used to determine statistical significance.

AD remained largely unaffected by the progressive ligament injury, irrespective of the applied torque. In the case of an isolated syndesmotic injury, AD measured 8.3 (±2.6) mm at 7.5 Nm of torque and increased slightly to 8.5 (±3.4) mm (P > .05) in the presence of a complete lateral ligament lesion. In contrast, TCS and PD demonstrated mixed results following the additional lateral ligament injury, without showing a consistent trend (Table 1).

In the second part (2) of the study, newly analyzed measures yielded high interrater reliability, with coefficients of 0.846 (P < .001) for the MGA and 0.793 (P < .001) for the LGA. The MGA is highly consistent when compared with the contralateral side, showing a mean difference of 0.2° (±3°). Similarly, the comparison with the contralateral side demonstrates a stable difference across all torque levels.

In contrast to the tibiofibular values, MGA increased significantly (P < .001 at 2.5 Nm; P < .001 at 7.5 Nm) from intact ligaments to a transected sydesmosis with fibular ligaments lesion across all torque levels (Figure 4).

Figure 4.

Figure illustrates rotational instability using the absolute values of the MGA, which reflects talar rotation relative to the medial malleolus. MGA increases progressively across the intact, syndesmotic injury, and lateral ligament injury conditions. at, Achilles tendon; Lm, lateral malleolus; Mm, medial malleolus; ta, anterior tibial tendon.

Even at the lowest applied rotational torque of 2.5 Nm, the measured angle increased from 16.7° ± 5.3° with a syndesmotic lesion to 22.0° ± 5.8° with an additional lateral ligament rupture (P < .05) (Table 2).

Table 2.

Tibiotalar and Fibulotalar Gutter Angles According to the Type of Lesion and Stratified by the Applied Torque Levels.^a

	Intact Ligaments	AITFL Lesion	Complete Syndesmosis Lesion	Syndesmosis + ATFL Lesion	Syndesmosis + ATFL + CFL Lesion	Syndesmosis + ATFL + CFL + PTFL Lesion
2.5 Nm
MGA (°)	11.0 ±3.1	12 ±2.8	16.7 ±5.3	18.6 ± 5.4	18.8 ± 5.2	22.0 ± 5.8
LGA (°)	4.1 ±2.8	7.3 ±5.4	7.3 ±4.8	5.5 ± 3.7	7.2 ± 4.8	8.5 ± 4.1
5.0 Nm
MGA (°)	14 ± 2.7	16.8 (4.1	19.3 ± 6.5	21.5 ± 6.1	22.1 ± 4.9	24.9 ± 3.7
LGA (°)	5.5 ±2.0	7.0 ±5.2	7.4 ± 4.5	7.4 ± 4.6	6.5 ± 2.8	10.3 ± 6.4
7.5 Nm
MGA (°)	16.3 ±2.8	18.5 ±2.6	22.9 ± 5.4	23.3 ± 5.8	25.6 ± 4.6	27.6 ± 6.3
LGA (°)	7.9 ±3.9	8.2 ±5.1	9.0 ±4.5	7.3 ± 4.0	7.2 ± 4.0	12.2 ±9.0

Abbreviations: AITFL, anteroinferior tibiofibular ligament; ATFL, anterior talofibular ligament; CFL, calcaneofibular ligament; LGA, lateral tibiotalar gutter angle; MGA, medial tibiotalar gutter angle; PTFL, posterior talofibular ligament.

From left to right, the degree of ligament injury increases, ranging from an intact ligamentous complex to progressive syndesmotic instability and, ultimately, to lateral ligament injury.

When analyzed by dissection pattern (pronation-external rotation pattern and supination-external rotation pattern groups), specimens with deltoid ligament ( pronation-external rotation pattern group) dissection showed greater MGA than those with PITFL (supination-external rotation pattern group) dissection (Figure 5), although this difference did not reach statistical significance.

Figure 5.

The Delta MGA values between the healthy and the injured side are displayed, combining all torque levels. The MGA values are depicted, broken down by dissection. Blue denotes the group with AITFL/IOL/DL, whereas red represents the group with AITFL/IOL/PITFL dissection. The increase was significant in both groups. In the intact condition and with dissection of the AITFL, there is no evident difference; however, with dissection of the DL in one group and the PITFL in the other, there is a nonsignificant trend toward higher MGA in the DL group.

For LGA, mean values increased from 9.0° (±4.5) in isolated syndesmotic injury to 12.2° (±9.0) (P > .05) after complete lateral ligament disruption.

Discussion

This is the first biomechanical investigation to assess the effect of lateral ligament injury on BET-CT measurements in unstable syndesmotic lesions as well as quantify its rotational instability. We found that adding lateral ligament lesions to an isolated syndesmotic injury did not alter AD. However, tibiotalar rotational instability, reflected by MGA, increased significantly with sequential lateral ligament sectioning. These results partially support our hypothesis: although disconnection between the talus and fibula permitted greater talar external rotation, this did not translate into reduced AD.

The progressive increase in angular deviation under torque further indicates that rotational laxity is amplified when syndesmotic injury is accompanied by lateral (and medial) ligament disruption. An association between tibiofibular widening and lateral instability has been described before.¹⁶ Widening has also been observed when a medial ligament rupture occurs in combination with a partial syndesmotic injury, underscoring the biomechanical relevance of this study.¹⁷ This further emphasizes the clinical importance of the injury patterns investigated in the present study. Various methods for diagnosing syndesmotic injury and evaluating stability have been described in both cadaveric and clinical settings, including analyses of individual ligament contributions and normal values.^3,5,6,18 BET-CT offers precise, repeatable, and minimally invasive assessment and is well suited for routine clinical use.^4,15 However, the role of the lateral ligament complex (ATFL, CFL, PTFL) has been addressed only in a limited number of studies, and its impact on external rotation testing remains largely unclear. This study demonstrates that established measurement parameters, such as AD, remain reliable even in the presence of a rupture of the lateral ligament complex.

A biomechanical cadaver study using fluoroscopic stress testing reported that isolated syndesmotic injury has no effect on lateral ankle instability, but may contribute to it when combined with lateral ligament lesions.¹⁹ Lateral instability worsened when both syndesmotic and lateral ligaments were disrupted. Although our study did not assess lateral tilt instability, we likewise observed increasing tibiotalar motion with progressive lateral ligament sectioning, specifically in rotational movement. Because tibiofibular stability was not evaluated here, no conclusions can be drawn regarding changes in syndesmotic widening in the presence of additional lateral ligament injury.

For the first time, BET-CT enabled direct quantification of tibiotalar rotational instability. To date, CT investigations under external rotation have predominantly described tibiofibular diastasis and mobility.^4,18,20 This study is the first to additionally examine their relationship to the talus. Previously, this instability had only been identified fluoroscopically and described as a translational shift, which according to our investigation could also be a sole rotation of the talus within the ankle mortise (Figure 6). Medial clear space widening can reflect 2 different pathologic mechanisms: a true diastasis characterized by lateral translation of the talus, or, when evaluated intraoperatively using rotational stress of the foot, a purely rotational phenomenon, manifested as medial gutter asymmetry. Rotational instability has long been recognized, yet reliably measuring and quantifying it has remained challenging.²¹ The newly introduced MGA measurement may offer a reproducible solution. Because it can be compared to the contralateral side, it is less affected by the applied torque level. However, its clinical relevance still needs to be validated in future studies. Based on the 2 different injury patterns investigated (supination-external rotation pattern / pronation-external rotation pattern), the effect of the deltoid ligament on rotational instability could be evaluated (Figure 5). No significant differences were detected. Nevertheless, a potential trend indicated that medial ligament injury may contribute to increased rotational instability when associated with partial syndesmotic lesion compared with a complete syndesmotic lesion. This observation is in line with previous literature demonstrating that, in the hook test, a partial syndesmotic injury may lead to instability when an additional deltoid ligament lesion is present.¹⁷ This effect might become statistically significant with a larger cadaver sample size; however, this remains speculative at this stage.

Figure 6.

Shown is an osseus 3D model where the talus is rotated 20° externally to simulate an ankle joint without (top) and with (bottom) external rotational torque. The red dashed line indicates the level of the medial malleolus, which is depicted on the left side. It demonstrates that with 20° of rotation in the anteroposterior view, the MGA appears as a pronounced medial shift.

This study has several limitations. First, the sample size was limited to 7 cadaveric pairs (14 lower extremities), which may limit statistical power and generalizability. The specimens had a mean age of 78.6 years, and age-related changes in bone and soft tissue properties may not reflect the biomechanics of younger, more active patients typically sustaining these injuries.

Second, testing was performed under static external rotation torque in a neutral ankle position. This does not replicate dynamic, weightbearing conditions or the influence of muscle activation, all of which affect ankle stability in vivo.

Third, although significant changes in rotational instability (MGA) were found, the clinical implications of these angular deviations remain to be fully validated, especially in terms of thresholds for surgical decision-making or long-term outcomes. Furthermore, ankles with isolated lateral ligament injury and an intact syndesmosis were not available as a control group as the syndesmotic ligaments had already been injured in a preceding experimental study using the same specimens. Consequently, the specific contribution of syndesmotic/lateral/medial ligament injury to the observed rotational instability cannot be fully identified to one specific ligament.

Conclusion

Additional injury to the fibular ligaments does not compromise BET-CT assessment of subtle syndesmotic instabilities when using the anterior tibiofibular distance. However, an increased MGA indicates rotational tibiotalar instability with progressive fibular ligament disruption. MGA appears to be a reliable and reproducible parameter for quantifying rotational instability in the cadaveric model evaluated, pending validation in clinical studies.

Supplemental Material

sj-pdf-1-fao-10.1177_24730114261443310 – Supplemental material for Bilateral External Rotation Torque CT Remains Reliable in Syndesmotic Assessment Despite Lateral Ligament Injury, but Reveals Increased Tibiotalar Rotational Instability

Supplemental material, sj-pdf-1-fao-10.1177_24730114261443310 for Bilateral External Rotation Torque CT Remains Reliable in Syndesmotic Assessment Despite Lateral Ligament Injury, but Reveals Increased Tibiotalar Rotational Instability by Pascal R. Furrer, Jeroen Grigioni, Anna-Katharina Calek, Lukas Comolli, Arnd F. Viehöfer, Jess G. Snedeker, Stephan H. Wirth and Silvan Beeler in Foot & Ankle Orthopaedics

Footnotes

Acknowledgements

The authors thank the Swiss Center for Musculoskeletal Imaging (SCMI) and Sara Erostrato in particular for their support with CT imaging and technical assistance throughout the study.

ORCID iDs

Pascal R. Furrer, MD,

Anna-Katharina Calek, MD,

Ethical Considerations

This study was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of the University of Zurich (BASEC-Nr. 2021-02179).

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Disclosure forms for all authors are available online.

References

Khambete

Harlow

Ina

Miskovsky

Biomechanics of the distal tibiofibular syndesmosis: a systematic review of cadaveric studies. Foot Ankle Orthop. 2021;6(2):24730114211012701. doi:10.1177/24730114211012701

Watson

Lucas

Simpson

Berlet

Hyer

CF.

Arthroscopic evaluation of syndesmotic instability in a cadaveric model. Foot Ankle Int. 2015;36(11):1362-1368. doi:10.1177/1071100715589631

Hunt

Goeb

Behn

Criswell

Chou

Ankle joint contact loads and displacement with progressive syndesmotic injury. Foot Ankle Int. 2015;36(9):1095-1103. doi:10.1177/1071100715583456

Beeler

Ongini

Hochreiter

et al. Bilateral External Torque CT Reliably Detects Syndesmotic Lesions in an Experimental Cadaveric Study. J Bone Joint Surg Am. 2024;106(6):542-552. doi:10.2106/jbjs.23.00412

Massri-Pugin

Lubberts

Vopat

Guss

Hosseini

DiGiovanni

CW.

Effect of sequential sectioning of ligaments on syndesmotic instability in the coronal plane evaluated arthroscopically. Foot Ankle Int. 2017;38(12):1387-1393. doi:10.1177/1071100717729492

Lubberts

Massri-Pugin

Guss

, et al. Arthroscopic assessment of syndesmotic instability in the sagittal plane in a cadaveric model. Foot Ankle Int. 2020;41(2):237-243. doi:10.1177/1071100719879673

Burssens

Krähenbühl

Weinberg

Lenz

Saltzman

Barg

Comparison of external torque to axial loading in detecting 3-dimensional displacement of syndesmotic ankle injuries. Foot Ankle Int. 2020;41(10):1256-1268. doi:10.1177/1071100720936596

Gosselin-Papadopoulos

Hébert-Davies

Laflamme

, et al. Intraoperative torque test to assess syndesmosis instability. Foot Ankle Int. 2019;40(4):408-413. doi:10.1177/1071100718816674

Guyton

DeFontes

Barr

Parks

Camire

LM.

Arthroscopic correlates of subtle syndesmotic injury. Foot Ankle Int. 2017;38(5):502-506. doi:10.1177/1071100716688198

10.

Krähenbühl

Bailey

Presson

, et al. Torque application helps to diagnose incomplete syndesmotic injuries using weight-bearing computed tomography images. Skeletal Radiol. 2019;48(9):1367-1376. doi:10.1007/s00256-019-3155-1

11.

Gaube

Maßen

Polzer

, et al. Syndesmotic and deltoid injuries: companions or coincidences. Foot Ankle Int. 2024;45(11):1239-1246. doi:10.1177/10711007241274712

12.

Raheman

Rojoa

Hallet

, et al. Can weightbearing cone-beam CT reliably differentiate between stable and unstable syndesmotic ankle injuries? a systematic review and meta-analysis. Clin Orthop Relat Res. 2022;480(8):1547-1562. doi:10.1097/CORR.0000000000002171

13.

Randell

Marsland

Ballard

Forster

Lutz

MRI for high ankle sprains with an unstable syndesmosis: posterior malleolus bone oedema is common and time to scan matters. Knee Surg Sports Traumatol Arthrosc. 2019;27(9):2890-2897. doi:10.1007/s00167-019-05581-5

14.

Mollon

Wasserstein

Murphy

White

Theodoropoulos

High ankle sprains in professional ice hockey players: prognosis and correlation between magnetic resonance imaging patterns of injury and return to play. Orthop J Sports Med. 2019;7(9):2325967119871578. doi:10.1177/2325967119871578

15.

Calek

Ongini

Hochreiter

Sutter

Wirth

Beeler

. The contralateral ankle joint is a reliable reference for testing syndesmotic stability using bilateral external torque CT. Foot Ankle Int. 2024; 45(9):1018-1026. doi:10.1177/10711007241262771

16.

Cheng

Liu

, et al. Arthroscopic characteristics and risk factors for syndesmosis widening in chronic lateral ankle instability: a cross-sectional study of 521 patients. Foot Ankle Int. 2025;46(9):1016-1024. doi:10.1177/10711007251344270

17.

Massri-Pugin

Lubberts

Vopat

Wolf

DiGiovanni

Guss

Role of the deltoid ligament in syndesmotic instability. Foot Ankle Int. 2018;39(5):598-603. doi:10.1177/1071100717750577

18.

Shamrock

Den Hartog

Dowley

, et al. Normal values for distal tibiofibular syndesmotic space with and without subject-driven external rotation stress. Foot Ankle Int. 2024;45(1):80-85. doi:10.1177/10711007231205576

19.

Bhimani

Sato

Saengsin

, et al. Fluoroscopic evaluation of the role of syndesmotic injury in lateral ankle instability in a cadaver model. Foot Ankle Int. 2022;43(11):1482-1492. doi:10.1177/10711007221116567

20.

Lehtola

Kortekangas

Pakarinen

, et al. Rotational dynamics of the distal tibiofibular joint after operative treatment of ankle fractures with syndesmosis injury. Foot Ankle Int. 2026;47(2):216-223. doi:10.1177/10711007251392222

21.

Aicale

Maffulli

Rotational ankle instability: a current concept review. J Orthop Surg (Hong Kong). 2023;31(2):10225536231182347. doi:10.1177/10225536231182347

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.00 MB

0.36 MB