BACKGROUND: Previous reports suggest that prolonged instability of the ankle may contribute to development of osteochondral lesions and eventually lead to osteoarthritis. However, no studies have directly compared osteochondral lesions in ankles with chronic lateral ankle instability (CLAI) to those without instability. This study was performed to determine characteristics and resulting clinical outcomes associated with osteochondral lesions of the talus (OLT) in patients with and without instability.
METHODS: Of 420 patients who underwent primary arthroscopic marrow stimulation for OLT, 74 patients were identified as having concomitant CLAI. After considering age, sex, body mass index, and initial trauma history for the propensity score (1:2 ratio), a total of 148 patients without CLAI were matched from the remainder of the cohort. Demographics and lesion characteristics were compared using preoperative magnetic resonance imaging (MRI) and arthroscopy. Clinical outcomes were compared using a visual analog scale (VAS), the American Orthopaedic Foot & Ankle Society (AOFAS) ankle score, and the Foot and Ankle Outcome Score (FAOS).
RESULTS: The OLT group with CLAI presented a significantly increased proportion of lateral-side OLT, large OLT (150 mm(2) or larger), and chondral lesions at the tip of the medial malleolus (P = .018, P = .024, and P < .001, respectively). VAS and AOFAS scores were comparable at the last follow-up. However, the OLT with CLAI group also exhibited a significantly increased proportion of failure (AOFAS score less than 80) and inferior outcomes in the FAOS for the sport and recreation subscale (P = .034 and P = .005, respectively).
CONCLUSIONS: Compared with osteochondral lesions in ankles without CLAI, osteochondral lesions in an unstable ankle had an increased proportion of larger lesions (150 mm(2) or larger) and additional chondral lesions at the tip of the medial malleolus and the tibia plafond. This group also displayed increased clinical failure (AOFAS score less than 80). Inferior performance in sport and recreational activities may be more likely in patients with both OLT and CLAI.