Autologous Chondrocyte Implantation and Osteochondral Allograft Transplantation Render Comparable Outcomes in the Setting of Failed Marrow Stimulation

Abstract

Background: Marrow stimulation techniques (MSTs) such as subchondral drilling and microfracture are often chosen as first-line treatment options for symptomatic cartilage defects of the knee. When an MST fails, many cartilage restoration techniques are employed, including autologous chondrocyte implantation (ACI) and osteochondral allograft (OCA). However, a few series in the literature suggest that ACI after a failed MST results in inferior outcomes as compared with primary ACI. Purpose/Hypothesis: The purpose of this study was (1) to evaluate the clinical outcomes of ACI and OCA after a failed MST (secondary ACI and OCA) and compare them with the outcomes of primary ACI and OCA and (2) to compare clinical outcomes of secondary ACI and secondary OCA for refractory lesions involving the femoral condyle. The hypotheses were as follows: (1) secondary ACI will render inferior functional outcomes and an increased clinical failure rate as compared with primary ACI, (2) secondary OCA will render comparable results to primary OCA, and (3) secondary OCA will render superior outcomes to secondary ACI. Study Design: Cohort study; Level of evidence, 3. Methods: Patients were retrospectively identified who underwent ACI and OCA for symptomatic chondral lesions of the knee refractory to a previous MST. Age-, sex-, and body mass index–matched groups of patients undergoing primary ACI and OCA were used as controls. Postoperative data were prospectively collected using several subjective scoring systems (Tegner, Lysholm, International Knee Documentation Committee, Knee injury and Osteoarthritis Outcome Score, 12-Item Short Form Health Survey). Groups were compared with regard to patient-reported outcomes, subjective satisfaction, clinical failure rate, and reoperation. Student t tests were used for continuous data, and chi-square tests were performed for categorical data. Results: A total of 359 patients were examined: 92 patients undergoing secondary ACI, 100 primary ACI, 88 secondary OCA, and 79 primary OCA. The mean patient age was 30.3 years (range, 14.9-49.9 years) at the time of ACI and 35.4 (range, 15-54.5) at the time of OCA. There was no difference between the primary and secondary groups with regard to postoperative functional scores, subjective satisfaction, reoperation rate, and clinical failure rate. Conclusion: ACI and OCA are both viable treatment options for chondral defects of the knee, even in the setting of a failed MST. Secondary ACI renders functional outcomes, subjective satisfaction, and reoperation and failure rates comparable with primary ACI and secondary OCA.