Journal of Foot and Ankle Surgery - 2026-07-25 - Journal Article
3D-MRI Based Morphometrics of Subtalar Ligaments: Insights for the Assessment of Ankle Sprains.
Vermorel PH, Grange R, Pintore A, Bergandi F, Philippot R, Grange S
Topics
Key Takeaway
3T 3D-MRI consistently visualizes all four principal subtalar ligaments (IER, CL, ITCL, CFL) in asymptomatic ankles, providing normative morphometric reference values (e.g., ITCL width 10.0 ± 1.4 mm, CFL thickness 2.8 ± 0.6 mm) to benchmark against injured counterparts.
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Summary
This descriptive anatomo-radiological study characterized the MRI morphology of the IER, CL, ITCL, and CFL in 17 asymptomatic contralateral ankles of patients who had undergone lateral ankle ligament repair, using 3T 3D-MRI with multiplanar reconstructions aligned to each ligament's axis. All four ligaments were consistently identified, with mean lengths of 34.6 mm (IER), 19.0 mm (CL), 16.9 mm (ITCL), and 25.2 mm (CFL). The study establishes normative length, width, and thickness values intended to serve as a reference standard for diagnosing subtalar ligament injury.
Key Limitation
The sample of n=17 is underpowered to account for morphometric variation by sex, BMI, or foot morphotype, limiting generalizability of the normative reference ranges.
Original Abstract
BACKGROUND
Subtalar ligament injuries occur in 10-25% of lateral ankle sprains (LAS) but remain underdiagnosed, partly because their radiological anatomy is insufficiently defined.
PURPOSE
This anatomo-radiological study aimed to systematically characterize the MRI appearance and anatomical morphology of the principal subtalar ligaments.
STUDY DESIGN
Descriptive, single-center anatomo-radiological reference study (Level IV).
METHODS
Seventeen patients underwent 3-Tesla 3D-MRI of the contralateral asymptomatic ankle after lateral ankle ligament repair. The inferior extensor retinaculum (IER), cervical ligament (CL), interosseous talocalcaneal ligament (ITCL), and calcaneofibular ligament (CFL) were evaluated on multiplanar reconstructions aligned with each ligament's axis. Length, width, and thickness were measured in all cases.
RESULTS
The mean age of the cohort was 35 ± 12.5 years; 7 women and 10 men were included, with a mean BMI of 28 ± 6.3 kg/m². All four ligaments were consistently visualized on 3D-MRI. Length, width, and thickness measured 34.6 ± 6.8, 5.6 ± 1.2, and 1.7 ± 0.2 mm for the IER; 19.0 ± 1.6, 5.3 ± 1.3, and 1.8 ± 0.5 mm for the CL; 16.9 ± 2.4, 10.0 ± 1.4, and 2.4 ± 0.9 mm for the ITCL; and 25.2 ± 4.8, 5.8 ± 2.0, and 2.8 ± 0.6 mm for the CFL.
CONCLUSIONS
This study provides reference identification methods and normative measurement values for 3D-MRI assessment of the IER, CL, ITCL, and CFL. These data improve the understanding of subtalar ligament morphology and may aid in the diagnosis and treatment of subtalar ligament injuries.
LEVEL OF EVIDENCE
Level IV (descriptive study).