Effect of Lower Limb Alignment and Corrective Osteotomy on Clinical Outcomes After Matrix-Associated Autologous Chondrocyte Implantation for Extensive Cartilage Defects of the Knee.

Background: The effectiveness of matrix-associated autologous chondrocyte implantation (MACI) in patients with lower limb malalignment remains debatable. Hypothesis: Performing MACI in patients with lower limb alignment abnormalities would result in worse postoperative outcomes than in those without alignment abnormalities. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who underwent MACI using autologous cultured cartilage for traumatic chondral defects and osteochondritis dissecans across 3 institutions between February 2014 and August 2022 were reviewed. Osteotomy was recommended for patients with mechanical alignment (MA) <40% and performed on consenting patients. Evaluation included demographic and clinical variables, Lysholm Knee Score (LKS), Knee injury and Osteoarthritis Outcome Score (KOOS), International Cartilage Regeneration & Joint Preservation Society (ICRS) grade from second-look arthroscopy, and postoperative complications. Results: Of 96 cases, 39 showed normal alignment and did not require osteotomy, 44 showed varus alignment and underwent corrective osteotomy, and 13 showed varus alignment but declined osteotomy. All groups showed significant improvement in the LKS and KOOS at 2 years (all Conclusion: In patients with varus alignment, MACI outcomes were improved when osteotomy was performed to shift alignment toward valgus. The corrected varus group demonstrated cartilage repair status and clinical outcomes comparable with those of the normal alignment group.