Background/Purpose: The goal of this study was to compare radiographic and patient reported outcomes at a minimum of two-years post matrix-induced chondrocyte implantation (MACI) between standard intercondylar region biopsy and osteochondral loose body biopsy.
Methods: A retrospective study was performed on all pediatric ACI procedures from 2014 to 2017 at a single institution. Patients were split into two groups: one group had cartilage derived from a standard intercondylar biopsy (n=9), and the other group had cartilage derived from osteochondral loose bodies found withing the ipsilateral knee (n=10). At a minimum one-year post-implantation, MRIs of the operative knee were performed and three individual orthopaedic surgeons used the MOCART 2.0 knee score to assess the cartilage. Interclass correlation coefficients (ICC) were calculated between the two groups. International Knee Documentation Committee (IKDC) scores were determined at a minimum two-years after implantation. Differences between outcomes were compared using a Wilcoxon rank-sum test.
Results: The ICC between examiners for the MOCART scoring was excellent at 0.94. With regards to the MOCART score, the loose body group had an insignificant 17-point lower median score at 63 (IQR 59-89) compared to the intercondylar group at 80 (IQR 65-09) (p=0.151). With regards to the IKDC, the loose body group had an insignificant 2-point lower median score at 82 (IQR 65-95) compared to the intercondylar group at 84 (IQR 53-99) (p=0.902).
Conclusion: These results demonstrate that osteochondral loose bodies can be used as viable biopsies in MACI with no difference in functional and radiographic outcomes at two-years post-implantation. This may limit short and long term donor site morbidity.