Predictors of Outcomes of Microfracture for Osteochondral Lesions of the Talus

Abstract

Category: Ankle Introduction/Purpose: Microfracture has been widely published as a treatment modality for osteochondral lesions of the talus (OLT). However, little is known about the outcome predictors following microfracture for smaller-sized OLT (<100mm 2 ). This study sought to define the predictors of both clinical and magnetic resonance imaging (MRI) outcomes for small OLT treated with microfracture. Methods: A retrospective cohort study investigating patients who received arthroscopic microfracture for OLT (<10mm or 100mm 2 ) between 2008 and 2017 were evaluated. Multivariate regression models were used to evaluate factors affecting post- operative Foot and Ankle Outcome Scores (FAOS) and Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scores. Kaplan-Meier survival curves with log-rank test were constructed and endpoint was defined as the requirement of revision surgery. Results: Eighty-seven patients were included in the study. The mean follow-up time was 41.4+-28.7 months. The mean FAOS pain score significantly improved from 60.4+-14.8 preoperatively to 79.3+-12.8 at final follow-up (p<0.001). Patients with uncontained- type OLT had an approximately 9-point worse FAOS pain score compared to contained-type OLT (p=0.036). Patients with cystic OLT also had an approximately 9-point worse pain FAOS compared to non-cystic OLT (p=0.026). Patients with larger lesion sizes had worse postoperative MOCART scores (p=0.012). Both Uncontained-Cyst and Uncontained-Noncyst groups had significantly worse FAOS pain than the Contained-Noncyst group (p<0.001, p=0.026). Survival rates in uncontained and contained lesions were 51.5% and 84.4%, respectively (p=0.616). Conclusion: Lesion uncontainment and the existence of cysts are independent predictors of poor clinical outcome following arthroscopic microfracture for smaller-sized OLT (<100mm 2 ).