Medial cystic osteochondral lesions of the talus exhibited lower sports levels, higher cyst-presence rate, and inferior radiological outcomes compared with lateral lesions following arthroscopic bone marrow stimulation.

Purpose To compare the patient-reported outcomes and radiological outcomes of the patients with medial- and lateral-cystic osteochondral lesions of the talus (OLTs) following bone marrow stimulation (BMS). Methods Patients with cystic OLTs who underwent BMS between January 2016 and February 2021 were retrospectively analyzed, and the minimum follow-up time was more than 24 months. Patients were paired in a 1:1 ratio (medial-: lateral-cystic OLT; MC-OLT: LC-OLT) based on the OLT area within 30mm2, follow-up within 1 year, age within 5 years, and ligament surgery (Yes/No). The Visual analog scale, Foot and Ankle Ability Measure (FAAM)-Activities of Daily Life and Sports scores were assessed preoperatively and postoperatively. The magnetic resonance observation of cartilage repair tissue (MOCART) scores, and presence of cysts after BMS were also evaluated. Additionally, the receiver operating characteristic curve was performed. Results The matched patients were divided into the MC-OLT(n=31, 43.35±12.32 months) and LC-OLT groups (n=31, 43.32±14.88 months, P=.986). Thirty patients of each group achieved a power of 80% and an α = 0.05 in this study. The MC-OLT group showed significantly less improvement in FAAM-ADL and sports scores (P = .034, P <0.001, respectively), lower MOCART scores (80.80±11.91 vs. 86.00±8.50, P = .010), and higher presence-rate of cyst after BMS (45.16% vs. 16.12%, P = .013). Regarding FAAM sports scores, the LC-OLT group had significantly more patients exceeding the MCID (80.64% vs. 51.61%, P = .031). Furthermore, an OLT depth of 7.23mm (sensitivity: 78.6%; specificity: 70.6%) might serve as a cut-off value for predicting the presence of cysts in medial-cystic OLTs following BMS. Conclusion Medial cystic OLTs exhibited markedly lower sports levels, higher cyst-presence rate, and inferior radiological outcomes following BMS than lateral counterparts. Additionally, an OLT depth of 7.23mm could be the cut-off value for predicting the presence of cysts regarding medial-cystic OLTs after BMS. Level of Evidence Level III, retrospective comparative study.