T2 assessment and clinical outcome following autologous matrix-assisted chondrocyte and osteochondral autograft transplantation

Objective: Both, matrix-assisted chondrocyte transplantation (MACT) and osteochondral autograft transplantation (OCT), are applied for treatment of articular cartilage defects. While previous clinical studies have compared the respective outcome, there is no such information investigating the ultrastructural composition using T2 mapping comparing cartilage T2 values of the repair tissue (RT). Methods: Eighteen patients that underwent MACT or OCT for treatment of cartilage defects at the knee joint (nine MACT, nine OCT) were matched for gender (one female, eight male pairs), age (33.8), body mass index (BMI) (28.3), defect localization, and postoperative interval (41.6 months). T2 assessment was accomplished by T2 maps, while the clinical evaluation included the Lysholm and Cincinnati knee scores, a visual analogue scale (VAS) for pain, the Tegner activity scale, and the Short Form-36. Results: Global T2 values of healthy femoral cartilage (HC) were similar among groups, while T2 values of the RT following MACT (46.8 ms, SD 8.6) were significantly lower when compared to RT T2 values after OCT (55.5 ms, SD 6.7) (P = 0.048). MACT values were also significantly lower in comparison to HC (52.5 ms, SD 7.9) within MACT patients (P = 0.046), while OCT values were significantly higher compared to HC (49.9 ms, SD 5.1) within OCT patients (P = 0.041). The clinical outcome following MACT was consistently superior to that after OCT while only the Lysholm score reached the level of significance (MACT 77.0, OCT 66.8; P = 0.04). Conclusion: These findings indicate that MACT and OCT result in a different ultrastructural outcome, which is only partially represented by the clinical picture.