Clinical Outcome of Total Knee Arthroplasty After Prior Microfracture: A Matched Cohort Study.

Microfracture (MFX) is a common operation for articular cartilage lesions. Data for patients who underwent total knee arthroplasty (TKA) after previous MFX are limited. The purpose of this study was to determine the outcomes, complications, and factors that influence outcomes in patients with previous MFX compared with those without previous MFX. Between 2005 and 2014, twenty-one TKAs were performed at a single tertiary care academic institution in patients with prior history of MFX surgery. These patients were retrospectively reviewed and matched 2:1 to patients who did not undergo previous MFX (n=42). Knee Society Score (KSS) (Subjective [KSS-S] and Function [KSS-F]) and complications were documented. Mean KSS-S in the MFX group increased significantly less (52.9 to 77.6) (P<.01) compared with the control group (51.3 to 83.8) (P<.01). The MFX group also demonstrated significantly less improvement in KSS-F from 63.0 to 88.9 (P=.02), whereas the control group demonstrated improvement from 52.4 to 87.1 (P=.02). At 5 years, the failure rate was 4.8% in the MFX group and 2.4% in the control group. Multivariate analysis found that older age at TKA resulted in smaller improvement in KSS-S. Paired relationships between increased age and decreased preoperative range of motion and women with an increased body mass index negatively affected KSS-S. Survivorship was similar between groups, but patients with MFX had slightly less clinical improvement compared with a matched control group. This study suggests that underlying patient factors may limit clinical improvement compared with primary TKA. [Orthopedics. 2017; 40(3):e473-e478.].