Microfracture effectively fills majority of talus osteochondral lesions at 4–6 months in patients with concomitant chronic lateral ankle instability: a second-look arthroscopy study of staged surgery

BACKGROUND: Microfracture (MF) is the first-line treatment strategy for Osteochondral lesions of the talus (OLT), while its clinical outcomes have been reported, the early-stage (4-6 months) healing effects of MF for OLT has been poorly characterized. This study investigated the early MF repairing outcomes in patients with concurrent OLT and CLAI treated with staged surgery. METHODS: We retrospectively evaluated 34 consecutive patients with concomitant OLT and CLAI who underwent staged surgery, consisting of first-stage MF for OLT and second-stage modified Brostrom-Gould repair with second-look arthroscopy. Repair quality was assessed using the Ferkel and Cheng staging system and the International Cartilage Repair Society (ICRS) score. Preoperative and postoperative magnetic resonance imaging (MRI) was evaluated using the Hepple classification. Clinical outcomes were assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) and visual analog scale (VAS) scores. Spearman correlation analysis was used to examine associations among preoperative variables, postoperative clinical scores, and second-look repair grades. RESULTS: All lesions showed effective filling at second-look arthroscopy; however, four patients with contiguous lesions involving zones 4 and 1 underwent revision MF because of poor integration in anterior zone 1. According to the Ferkel and Cheng system, repair quality was Grade A in 2.9%, Grade B in 70.6%, Grade C in 20.6%, and Grade D in 5.9% of cases. MRI demonstrated nearly intact cartilage surfaces with persistent subchondral bone edema. Hepple classification showed a trend toward improvement (Z = - 1.83, p = 0.070). AOFAS and VAS scores improved significantly by the second procedure. Preoperative subchondral bone cysts and lesion number were not significantly associated with repair quality. No significant correlation was found between arthroscopic repair grades and clinical scores at early follow-up. CONCLUSION: MF achieved satisfactory early filling in most OLTs at 4-6 months in patients with concomitant CLAI undergoing staged surgery. However, integration in anterior zone 1 warrants particular attention in lesions extending across zones 4 and 1. CASE SERIES: Level of evidence, 4.