A larger defect size and more prior surgical procedures are negatively associated with radiological outcome 10 years after tibiofemoral matrix-induced autologous chondrocyte implantation.

Abstract

To investigate factors associated with radiological graft outcome 10 years after tibiofemoral matrix-induced autologous chondrocyte implantation (MACI). This retrospective study included 96 patients that underwent MACI to the medial (n = 72) or lateral (n = 24) femoral condyle. All patients underwent pre-operative review, as well as 10-year clinical and radiological review. Regression analysis assessed the contribution of baseline demographic, injury, surgical and activity (KOOS Sport and Recreation subscale) parameters, to 10-year graft-related MRI outcomes including: (1) the magnetic resonance observation of cartilage repair tissue (MOCART) score and (2) tissue infill (greater or less than 50% tissue infill). The mean 10-year MOCART score was 2.9 ± 0.6 (out of 4.0). For tissue infill, 53.1% (n = 51) of patients demonstrated infill at (or beyond) the adjacent native cartilage, 83.3% (n = 80) had greater than 50% infill compared with the native cartilage, and six patients (6.3%) demonstrated graft failure (subchondral bone exposed). The KOOS Sport and Recreation subscale improved from baseline to 10-years by a mean 44.0 points (95% CI, 38.0-50.0; p < 0.001). In the final multivariable model, defect size (p = 0.012) and the number of prior knee procedures (p = 0.012) were significant predictors of graft infill. The only variable that was a significant predictor of the MOCART score was defect size (p = 0.015). Encouraging long-term clinical and MRI-based outcomes were observed after MACI. A greater number of prior procedures and a larger defect size were associated with a worse long-term MRI-based graft outcome. This information is important in providing realistic expectations to patients on longer-term graft survivorship. Level IV.