Risk factors and clinical significance of functional outcomes after microfracture-based surgical treatment of osteochondral lesion of the talus

The aims of the current study are to identify risk factors after microfracture-based surgical treatment of osteochondral lesion of the talus (OLT), and to determine the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) values for clinical outcomes.

The relationship between the superior and inferior outcome (Karlsson score < 90) groups in the bivariate analysis was tested with the independent t-test or Fisher exact test. A multivariate logistic regression model and a multiple linear regression model were developed to investigate the influence of the selected factors on inferior outcome. The MCID, SCB, and PASS for the American Orthopedic Foot and Ankle Society (AOFAS) score, visual analogue scale for pain (VAS score), and Karlsson scores were derived through anchor-base methods.

One hundred and thirty-seven patients were followed up for 49.9 ± 17.2 months. Longer symptom duration (adjusted odds ratio, 1.015; 95% Confidential Interval (CI), 1.002 to 1.027; p = 0.020), and higher fasting blood glucose (adjusted odds ratio, 1.555; 95% CI, 1.066 to 2.270; p = 0.022) were independent predictors of inferior outcomes. Male gender (adjusted odds ratio, 0.317; 95% CI, 0.121 to 0.833; p = 0.020) and higher preoperative AOFAS score (adjusted odds ratio, 0.937; 95% CI, 0.887 to 0.989; p = 0.018) were independent predictors of superior outcomes. The MCID, SCB, and PASS values for the AOFAS score were 6.5, 10.5, and 85.5; for VAS score were 3.5, and 3.5 (SCB and PASS); and for Karlsson score were 15.5, 25.5, and 80.5, respectively.

Higher fasting blood glucose and lower preoperative functional scores are associated with inferior outcomes after microfracture-based surgical treatment for OLT. Reliable SCB and PASS values for AOFAS, VAS and Karlsson scores were obtained from patient evaluations after microfracture-based surgical treatment of OLT.

Level of evidence III Retrospective comparative series.