Evidence map›Paper›PMID 41606613›Full record

ArticleJournal of orthopaedic surgery and research2026

CPAK phenotypes in medial open wedge high tibial osteotomy: undercorrection as the key factor influencing clinical outcomes and cartilage regeneration.

Yao-Chang Lo, Chih-Hao Chang, Chen-Ti Wang, Hongsen Chiang, Chien-Lin Chen, Jyh-Horng Wang, Tzu-Hao Tseng

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Article in Journal of orthopaedic surgery and research, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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7 authors.

Yao-Chang LoDepartment of Orthopaedic Surgery, National Taiwan University Hospital, Taipei City, Taiwan.
Chih-Hao ChangDepartment of Orthopaedic Surgery, National Taiwan University Hospital, Taipei City, Taiwan.
Chen-Ti WangDepartment of Orthopaedic Surgery, National Taiwan University Hospital, Taipei City, Taiwan.
Hongsen ChiangDepartment of Orthopaedic Surgery, National Taiwan University Hospital, Taipei City, Taiwan.
Chien-Lin ChenDepartment of Orthopaedic Surgery, National Taiwan University Hospital, Taipei City, Taiwan.
Jyh-Horng WangDepartment of Orthopaedic Surgery, National Taiwan University Hospital, Taipei City, Taiwan.
Tzu-Hao TsengNational Taiwan University Hospital, No.7 Chungsan South Road, Taipei, 10002, Taiwan. b92401004@gmail.com.

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No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundMedial opening wedge high tibial osteotomy (MOWHTO) shifts the mechanical axis laterally to relieve medial knee stress. The CPAK classification, which categorizes knee alignment into nine phenotypes, has been scarcely applied in studies involving MOWHTO. The aim of this study is to explore the effect of CPAK phenotypes on cartilage regeneration and functional outcome after MOWHTO.

methodsThis was retrospective study involving 186 patients who underwent MOWHTO, with 103 of these patients receiving second-look arthroscopy. We analyzed pre- and postoperative CPAK phenotypes, along with factors such as age, sex, BMI, laterality, and undercorrection, to identify contributors to clinical outcomes. Outcomes were assessed through arthroscopic evaluation of cartilage regeneration and the Knee Injury and Osteoarthritis Outcome Score (KOOS) for the entire cohort.

resultsThis study included 81 men and 105 women, with a mean age of 60.3 years. The mean KOOS was 69.0 ± 12.1 at an average follow-up of 40.6 months. Among 103 patients who underwent second-look arthroscopy, 55.3% showed cartilage improvement. Univariate analysis revealed that postoperative CPAK phenotype and undercorrection correlated with KOOS, while age and postoperative CPAK phenotype correlated with cartilage improvement. Multivariate analysis identified undercorrection as the sole significant contributor to both postoperative KOOS and cartilage improvement.

conclusionsUndercorrection is the main factor affecting clinical outcomes and cartilage regeneration, rather than the specific CPAK phenotype. When proper correction is achieved, neither preoperative nor postoperative CPAK phenotypes significantly influence results, indicating that MOWHTO can achieve favorable outcomes even in the presence of femur-driven deformities or intra-articular wear.

Indexed as

Cartilage, ArticularOsteoarthritis, KneeOsteotomyPhenotypeRegenerationTibiaAgedArthroscopyFemaleFollow-Up StudiesHumansMaleMiddle AgedRetrospective StudiesTreatment OutcomeCartilageCPAK phenotypeHTOKOOSOsteoarthritis

Identifiers

PMID41606613
PMCPMC12924326

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