Effectiveness and Safety of Matrix-Associated Autologous Chondrocyte Implantation for the Treatment of Articular Cartilage Defects: A Real-World Data Analysis in Japan

Background: The effectiveness and safety of matrix-associated autologous chondrocyte implantation with an autologous periosteal flap (pMACI) remain unclear. The Japanese Ministry of Health, Labor, and Welfare requires postmarketing surveillance of all patients undergoing pMACI using the tissue-engineered product JACC. Purpose: To evaluate the effectiveness and safety of pMACI for large articular cartilage defects (≥4 cm 2 ) in the knee joint using real-world data analysis. Study Design: Case series; Level of evidence, 4. Methods: Data were collected from patients who underwent pMACI between 2012 and 2019, with 2 years of follow-up. The primary outcomes were the Lysholm knee score and Knee injury and Osteoarthritis Outcome Score (KOOS) at 6, 12, and 24 months. Adverse events were assessed by physical examination, magnetic resonance imaging, and/or arthroscopy. Results: Overall, 232 knees in 225 patients who presented with trauma (198 knees) or osteochondritis dissecans (34 knees) in the medial (132 knees) and lateral (44 knees) femoral condyle, patella (25 knees), trochlea (86 knees), and tibial plateau (4 knees) were included. The mean age of the patients was 40.9 ± 15.0 years, with mean cartilage defects of 5.6 ± 2.4 cm 2 in size. Concomitant surgeries, such as osteotomy (50 knees), ligament reconstruction (27 knees), meniscal procedures (28 knees), osteochondral autograft transplantation (24 knees), and microfracture (14 knees), were performed in 113 (48.7%) knees. The minimal clinically important difference in the Lysholm knee score and KOOS Symptoms subscale was achieved in 79.7% and 63.5% of patients, respectively, and the Patient Acceptable Symptom State was achieved in 90.1% and 73.7%, respectively. Substantial clinical benefit was achieved in the KOOS Sports/Recreation and Quality of Life subscales at 39.6% and 37.8%, respectively. Knees that underwent concomitant microfracture had significantly worse KOOS values than the remainder of the cohort. Complications, including effusion (16.8%), graft delamination (14.7%), knee contracture (9.1%), graft hypertrophy (8.2%), and ossification (3.4%), were observed in 86 (37.1%) knees. Osteochondritis dissecans was significantly associated with graft hypertrophy and ossification, whereas concomitant surgery was significantly associated with delamination and contracture. Treatment failure required additional cartilage procedures in 11 (4.7%) knees. Conclusion: Treatment of large cartilage defects (≥4 cm 2 ) with pMACI resulted in improved outcome scores in approximately 75% of patients. However, complications occurred in one-third of patients, and 4.7% required reoperation.