Correlation between the quality of cartilage repair tissue and patellofemoral osteoarthritis after matrix-induced autologous chondrocyte implantation at three-year follow-up: a cross-sectional study

Purpose To investigate whether the quality of cartilage repair tissue is associated with patellofemoral osteoarthritis (PFOA) at a three year follow-up after matrix-induced autologous chondrocyte implantation (MACI). Methods This retrospective study included 32 patients who underwent MACI between October 2014 and May 2018 at our institute. The Lysholm score and Visual Analog Scale (VAS) score were assessed. The magnetic resonance observation of cartilage repair tissue (MOCART) 2.0 score and T2* relaxation time of repair tissue were used to evaluate cartilage repair tissue quality. A modified MRI Osteoarthritis Knee Score (mMOAKS) was used to evaluate PFOA. Results Compared with pre-operative scores, the final Lysholm score (50.71 +/- 2.22 vs 89.70 +/- 1.18; t = 15.5, P < 0.0001) and VAS score (4.67 +/- 0.47 vs 0.92 +/- 0.64; t = 22.62, P < 0.0001) were improved at 3 years after MACI. At the three year follow-up, the mean MOCART 2.0 score was 61.56 +/- 18.11, and the T2* relaxation time of the repair tissue was significantly lower than that in the healthy control region (24.11 +/- 6.38 vs 34.39 +/- 1.33, t = - 8.635, P < 0.0001). The mean mMOAKS score was 9.16 +/- 4.51. On univariate analysis, the MOCART 2.0 score and T2* relaxation time were negatively associated with the mMOAKS score. Conclusion MACI can lead to significant pain relief and restoration of knee joint function, and good quality cartilage repair tissue was a protective factor against PFOA at the three year follow-up.