Comparison of Arthroscopic Microfracture for Osteochondral Lesions of the Talus With and Without Subchondral Cyst

Background: Although various treatment modalities for an osteochondral lesion of the talus (OLT) with a subchondral cyst have been recommended previously, the primary treatment methods for such conditions have yet to be conclusively determined. Moreover, few comprehensive studies have compared the outcomes of cases where patients were treated with microfracture for OLT with and without subchondral cysts. Purpose: To evaluate the clinical outcomes after arthroscopic microfractures performed as a primary treatment for OLT with a subchondral cyst. Study Design: Cohort study; Level of evidence, 2. Methods: The study cohort consisted of 102 patients (102 ankles) who underwent arthroscopic microfracture for small to midsized OLT. The ankles were divided into a cyst group (45 ankles) and a noncyst group (57 ankles).The American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale, visual analog scale (VAS), and Ankle Activity Score (AAS) were used to compare the clinical outcomes between the groups over a mean follow-up period of 48 months. Results: The mean AOFAS ankle-hindfoot scores were 64.8 in the cyst group and 66.2 in the noncyst group preoperatively. These improved to 91.8 and 91.3, respectively, at the final follow-up. The mean VAS scores were 7.5 in the cyst group and 7.3 in the noncyst group preoperatively; these improved to 2.3 and 2.2, respectively, at the final follow-up. The mean AAS in the cyst group and the noncyst group improved from 2.7 and 2.6 preoperatively to 6.7 and 6.5 at the final follow-up, respectively. In terms of radiographic stage improvements, the cyst group showed no change in 18 ankles (40%) and showed improvements of 1 grade in 13 ankles (28.9%), 2 grades in 9 ankles (20%), 3 grades in 3 ankles (6.7%), and 4 grades in 2 ankles (4.4%). The noncyst group showed no change in 17 ankles (29.8%) and showed improvements of 1 grade in 11 ankles (19.3%), 2 grades in 11 ankles (19.3%), 3 grades in 14 ankles (24.6%), and 4 grades in 4 ankles (7.0%). No significant differences were found between the groups in terms of the AOFAS score, VAS score, AAS, or radiographic stage improvements. Conclusion: OLT with and without subchondral cysts treated with arthroscopic microfracture showed similarly good clinical results. The study results suggest that microfracture could be a primary treatment strategy for treating small to midsized OLT regardless of the existence of subchondral cysts.