Grade 3 and 4 articular cartilage defects involve 50% of cartilage thickness without involvement of the underlying bone. There are several available options for the surgical repair of articular cartilage lesions including osteochondral allograft transplantation (OCA), a well-established procedure, and autologous chondrocyte implantation (ACI), an alternative developed more recently. Although there are studies examining ACI outcomes, there hasn’t been significant comparison of ACI outcomes to other procedures, including OCA. The inquiry question of this study was: how do clinical and functional outcomes differ between patients with focal articular cartilage defects treated with ACI and patients treated with OCA?
After IRB approval, a database query identified patients who had undergone ACI or OCA between 2008 and 2016. Eligible patients were contacted via telephone and/or email to complete functional outcome surveys including the Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR.), International Knee Documentation Committee (IKDC), and the 12-Item Short Form (SF-12). A retrospective chart review was performed to obtain demographic information as well as information related to ACI and OCA. Statistical analysis was performed using a combination of a Fischer’s exact or chi-squared test, Mann-Whitney U test, and Kruskal-Wallis test, using a statistical significance value of P < 0.05.
The patient cohort was composed of 89 (50.6%) patients who had undergone ACI and 87 (49.4%) patients who had undergone OCA. The ACI group compared to the OCA group had a lower mean KOOS, JR. score (72.65 ± 16.93 vs 73.95 ± 18.91, p = 0.634), lower IKDC score (61.91 ± 21.12 vs 63.92 ± 22.55, p = 0.544), and higher SF-12 score (49.16 ± 7.46 vs 47.81 ± 9.61, p = 0.312) although none of the differences were statistically significant. Within the ACI group, no patients required revision surgery although 5 (5.6%) patients underwent total knee arthroplasty or OCA due to persistence of symptoms. Within the OCA group, 5 (5.7%) patients required revision surgery, while 7 (8.0%) patients underwent an additional procedure due to failure. A total of 16 (18.3%) patients, including 2 patients who underwent revision OCA, required conversion to total or unicompartmental arthroplasty, additional OCA procedure unrelated to previous OCA failure, or ACI due to persistence of symptoms. The rate of failure, defined as the need for revision or subsequent surgery to resolve symptoms, was significantly greater in the OCA group (25.3% vs 5.6%, p < 0.001).
The results of this study indicate that patients who underwent ACI for articular cartilage defects had statistically similar functional outcomes (KOOS, JR., IDKC, SF-12 scores) as patients who underwent OCA. However, the ACI group demonstrated a lower rate of failure compared to the OCA group. These findings may indicate a preference for ACI over OCA for the repair of grade 3 and 4 articular cartilage lesions in order to reduce the rate of subsequent surgeries and/or failure.
Abraham, Daniel; Brutico, Joseph; Chauhan, Kashyap; Dixit, Anant; Tjoumakaris, Fotios; Tucker, Brad; and Freedman, Kevin, "Differences in Clinical and Functional Outcomes Between Osteochondral Allograft Transplantation and Autologous Chondrocyte Implantation when Used in the Treatment of Focal Grade 3 and Grade 4 Articular Cartilage Defects" (2021). Phase 1. Paper 82.