Talar osteochondral lesions at mid- to long-term follow-up after surgically treated trimalleolar ankle fracture-dislocations: prevalence and radiological associations

Osteochondral lesions of the talus (OLTs) are increasingly recognized following ankle fracture-dislocations; however, their mid- to long-term prevalence and radiological associations remain insufficiently defined. This study aimed to evaluate the prevalence, localization, and radiological severity of talar osteochondral lesions after surgically treated ankle fracture-dislocations using comprehensive radiological assessment. This retrospective radiological follow-up study included 97 patients who underwent open reduction and internal fixation for trimalleolar ankle fracture-dislocations between 2014 and 2023, with a minimum follow-up of 36 months. All patients were evaluated using radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) at final follow-up. Osteochondral lesions were assessed using MRI- and CT-based classification systems, and fracture morphology was evaluated on preoperative CT. Firth penalized logistic regression analysis was performed to identify factors associated with osteochondral lesion detection at final follow-up, with follow-up duration included as a covariate. At a mean follow-up of 72.1 ± 28.0 months, osteochondral lesions were identified in 75 of 97 patients (77.3%), predominantly located at the medial talar dome (59/75, 78.7%). Most lesions were low-grade radiological findings, with Stage 1 lesions accounting for 44/75 (58.7%) on MRI, 48/75 (64.0%) on CT, and 45/75 (60.0%) on radiographs. In Firth penalized logistic regression adjusted for follow-up duration, neither posterior malleolar articular involvement (adjusted OR per 5% increase, 1.84; 95% CI, 0.82–4.13; p = 0.141) nor Chaput fracture (adjusted OR, 0.78; 95% CI, 0.08–7.23; p = 0.825) showed a significant adjusted association with radiologically detected osteochondral lesions at final follow-up. Chaput fractures were uncommon (5/97, 5.2%), with OLT detected in 4 of these 5 patients. In secondary severity analysis, greater posterior malleolar involvement was associated with non-stage-1 radiological lesions across MRI, CT, and radiographs (adjusted OR per 5% increase range, 5.19–6.47; all p < 0.001). OLTs were frequently detected at mid- to long-term radiological follow-up after surgically treated trimalleolar ankle fracture-dislocations, although most lesions were low-grade radiological findings. Greater posterior malleolar involvement was associated with more advanced radiological lesion severity, but not with the mere presence of OLTs at final follow-up. Because lesion onset could not be determined and clinical outcome measures were unavailable, these findings should be interpreted as radiological prevalence and severity-association findings rather than evidence of temporal lesion development or clinical prognosis. Level III, retrospective cohort study.