A Prospective Clinical and Radiological Evaluation at 5 Years after Arthroscopic Matrix-Induced Autologous Chondrocyte Implantation

Background: While midterm outcomes after matrix-induced autologous chondrocyte implantation (MACI) are encouraging, the procedure permits an arthroscopic approach that may reduce the morbidity of arthrotomy and permit accelerated rehabilitation. Hypothesis: A significant improvement in clinical and radiological outcomes after arthroscopic MACI will exist through to 5 years after surgery. Study Design: Case series; Level of evidence, 4. Methods: We prospectively evaluated the first 31 patients (15 male, 16 female) who underwent MACI via arthroscopic surgery to address symptomatic tibiofemoral chondral lesions. MACI was followed by a structured rehabilitation program in all patients. Clinical scores were administered preoperatively and at 3 and 6 months as well as 1, 2, and 5 years after surgery. These included the Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm knee scale (LKS), Tegner activity scale (TAS), visual analog scale for pain, Short Form-36 Health Survey (SF-36), active knee motion, and 6-minute walk test. Isokinetic dynamometry was used to assess peak knee extension and flexion strength and limb symmetry indices (LSIs) between the operated and nonoperated limbs. High-resolution magnetic resonance imaging (MRI) was performed at 3 months and at 1, 2, and 5 years postoperatively to evaluate graft repair as well as calculate the MRI composite score. Results: There was a significant improvement (P <.05) in all KOOS subscale scores, LKS and TAS scores, the SF-36 physical component score, pain frequency and severity, active knee flexion and extension, and 6-minute walk distance. Isokinetic knee extension strength significantly improved, and all knee extension and flexion LSIs were above 90% (apart from peak knee extension strength at 1 year). At 5 years, 93% of patients were satisfied with MACI to relieve their pain, 90% were satisfied with improving their ability to undertake daily activities, and 80% were satisfied with the improvement in participating in sport. Graft infill (P =.033) and the MRI composite score (P =.028) significantly improved over time, with 90% of patients demonstrating good to excellent tissue infill at 5 years. There were 2 graft failures at 5 years after surgery. Conclusion: The arthroscopically performed MACI technique demonstrated good clinical and radiological outcomes up to 5 years, with high levels of patient satisfaction.