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

Akira Maeyama; Kazuhiko Saeki; Tetsuro Ishimatsu; Taiki Matsunaga; Shizuhide Nakayama; Junya Hara; Takuaki Yamamoto

doi:10.1177/23259671251403094

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

Orthop J Sports Med. 2026 Jan 13;14(1):23259671251403094. doi: 10.1177/23259671251403094. eCollection 2026 Jan.

Authors

Akira Maeyama¹, Kazuhiko Saeki², Tetsuro Ishimatsu¹, Taiki Matsunaga¹, Shizuhide Nakayama¹, Junya Hara¹, Takuaki Yamamoto¹

Affiliations

¹ Department of Orthopaedic Surgery, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
² Department of Orthopaedic Surgery, Fukuoka Sanno Hospital, Fukuoka, Japan.

Abstract

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 P < .05). At 1 year, the normal alignment group showed superior LKS (P = .01) and KOOS Activities of Daily Living (ADL) subscale (P = .04) compared with the varus group without osteotomy. The varus group with osteotomy had significantly better LKS (P = .02) and KOOS ADL (P = .04) than the varus group without osteotomy. ICRS grade-based assessments of medial femoral condylar graft sites showed no significant difference between the normal alignment group and varus group with osteotomy (mean, 10.2 vs 10.0; P = .70). However, significantly worse graft-site repair was noted in patients with MA ≥60% (P = .004), although clinical outcomes were not significantly different. Eight complications were reported in the normal alignment group, with 4 each in the varus groups with and without osteotomy.

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.

Keywords: articular cartilage; autologous chondrocyte implantation; knee; osteotomy.