Summary

Osteochondral lesions of the talar dome can be found in 57.1% of athletes sustaining isolated unstable syndesmotic injuries. These injuries are commonly anterolateral and ICRS grade II with a mean area of 12.6 ± 4.9 mm2. MRI showed a sensitivity and specificity for diagnosing osteochondral lesions of the talar dome of 66.7% and 33.3%, respectively.

Abstract

Background

Osteochondral lesions of the talar dome (OLT) are frequently associated with traumatic injuries. They are present in 73% of ankle fractures and 50% of ankle sprains, although a minority have a specific reported location (28%) and individual patient OLT size (7%). This is worth noting for isolated syndesmosis injuries, in which OLT patterns have been scarcely described but have been correlated with delayed time to return to sports.

Objective

The present study aimed to assess the incidence and characteristics of OLT in preoperative MRI and anterior ankle arthroscopy in professional athletes with isolated unstable syndesmotic injuries undergoing surgical treatment.

Methods

A retrospective chart review was performed between January 2017 and October 2021. Inclusion criteria were: (1) professional athletes, (2) = 18 years old, (3) who were treated for isolated unstable syndesmosis injury with fixation within the first 12 weeks post-injury, and (4) preoperative magnetic resonance imaging (MRI) with or without arthroscopic assessment. Syndesmosis instability was defined as (1) two-ligament injuries on MRI with a positive squeeze test or (2) two-ligament injuries on MRI with arthroscopic findings of 2-mm mortise widening. The primary outcome was OLT incidence in preoperative MRI and arthroscopic assessment, while secondary outcomes included the characterization of these lesions as follows: location was identified in MRI and arthroscopy using the nine-zone grid scheme of Raikin et al. Injuries were classified according to Hepple et al. and ICRS. Injury size (length, width, and area) was measured using MRI and arthroscopically.

Results

A total of 27 athletes (88.9% male, 62.9% football players) were included. Seventeen patients (62.9%) had OLT on the preoperative MRI (55.6% isolated and 7.4% multiple). Nine defects (47.4%) were anteromedial: seven defects (36.8%) were anterolateral, two central (11.8%), and one posterior (5.9%). According to Hepple classification, twelve injuries were type 1 (63.2%), four type 2a (21.1%), two type 2b (10.6%), and one type 3 (5.3%). MRI mean defect length was 4.2 ± 2.2 mm (range, 1-10 mm). The width was not measurable on 13 lesions (68.4%). Twenty-one patients (77.8%) of this series had available operative reports from their anterior ankle arthroscopy. Twelve athletes (57.1%) had OLT, all isolated cartilage defects. Nine defects were located in zone 3 (75%), and the remaining three were located in zones 1, 2, and 6. Correspondingly, eleven lesions were ICRS grade II (91.7%) and one (8.3%) grade IV. The mean arthroscopic defect area was 12.6 ± 4.9 mm2 (range, 6-28 mm2). MRI showed a sensitivity and specificity for diagnosing OLT of 66.7% and 33.3%, respectively (location ICC 0.04, 95% CI -0.15 to 0.22; length ICC 0.24, 95% CI -0.15 to 0.57).

Conclusion

OLT can be found in 57.1% of athletes sustaining isolated unstable syndesmotic injuries. These injuries are commonly anterolateral and ICRS grade II with a mean area of 12.6 ± 4.9 mm2. MRI showed a sensitivity and specificity for diagnosing OLT of 66.7% and 33.3%, respectively.