Concomitant subchondral bone cysts negatively affect clinical outcomes following arthroscopic bone marrow stimulation for osteochondral lesions of the talus.

PURPOSE: To study the effects of concomitant subchondral bone cysts (SBCs) on prognosis following arthroscopic bone marrow stimulation (BMS) for osteochondral lesions of the talus (OLTs) less than 100mm2 and to further assess the correlation between cystic OLT area, depth, or volume and postoperative outcomes.

METHODS: We retrospectively analyzed consecutive patients with OLTs (＜100mm2 ) who received BMS between April 2017 and May 2020 with a minimum follow-up of 24 months. Lesion area, depth, and volume were collected on the preoperative magnetic resonance imaging. Visual analog scale (VAS), American Orthopedic Foot and Ankle Society, Karlsson-Peterson, Tegner, Foot and Ankle Ability Measure- Activities of Daily Life (FAAM-ADL) and Sports (FAAM-SP) scores were assessed preoperatively and at the latest follow-up. Additionally, a general linear model (GLM) and a Pearson correlation analysis (PCA) were performed to investigate the effects of concomitant cysts on postoperative results.

RESULTS: 82 patients with a mean follow-up of 39.22±12.53 months were divided into non-cyst (n=45; 39.91±13.03 months) and cyst (n=37; 38.37±12.02 months) groups. There was no significant difference in OLT area between non-cyst and cyst groups (46.98±19.95mm2 vs. 56.08±22.92mm2 ; P=.093), but the cyst group showed significantly greater depth (6.06±1.99mm vs. 3.96±1.44mm; P=.000) and volume (248.26±156.81mm3 vs. 134.58±89.68mm3 ; P=.002). The non-cyst group showed significantly more improvement in VAS pain, Karlsson-Peterson, Tegner, and FAAM scores than the cyst group (P<.05). The GLM indicated that SBCs negatively affected VAS pain and Tegner scores (P<.05). For OLTs with cysts, the PCA showed that an area of 90.91mm2 , depth of 7.56mm, and volume of 428.13mm3 were potential cut-off values associated with poor outcomes.

CONCLUSION: The concomitant SBCs negatively affected the prognosis of OLTs following BMS. For OLTs with cysts, an area of 90.91mm2 , depth of 7.56mm, and volume of 428.13mm3 were the potential cut-off values associated with poor outcomes after BMS.

LEVEL OF EVIDENCE: Level III, retrospective comparative study.