Talar-sided osteochondral lesion of the subtalar joint following the intra-articular calcaneal fracture: study via a modified computed tomography mapping analysis.

Introduction: This study is to report the prevalence of osteochondral lesions in subtalar joint following intra-articular calcaneal fracture, including the relationship between fracture severity and lesion characteristics, using modified computed tomography (CT) mapping analysis.

Methods: Thirty patients with intra-articular calcaneal fracture who were preoperatively imaged with modified CT mapping analysis were recruited. The presence of talar-sided osteochondral lesions (OLTS) of subtalar joint was noted with lesion area defined by Akiyama's mapping classification. Lesion severity was assessed via Ferkel's classification, and fracture severity via Sanders' classification.

Results: Lesions were found in 28 patients (93.3%), mostly at anterior [16 (57.1%) lesions] or central [13 (46.4%) lesions] areas of posterior talar facet. Most common grade of lesion severity was grade I (mild) seen in 24 (80%) patients. Most fractures were classified as Sanders' grade III and IV with 12 (40%) and 12 (40%) patients noted, respectively. High severity of fracture denoted by Sanders' grade IV showed a trend of higher prevalence of OLTS at anterior and central sites of posterior talar facet (P = 0.181). Lesion severity was significantly higher in patients with double lesions than patients with single lesions (P = 0.005). However, OLTS were not significantly related with osteoarthritic changes in follow-up radiographs (P > 0.05).

Conclusions: The prevalence of OLTS is very high following intra-articular calcaneal fractures. Most lesions occur at anterior or central area of posterior talar facet and are more likely to occur in patients with higher fracture severity. Lesion severity was significantly higher in patients with double lesions than patients with single lesions.