The distribution of femoral and tibial coronal alignment in Japan: a multicentric retrospective study of patients with knee osteoarthritis


Takashi Tsuda
JAPAN

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The distribution of femoral and tibial coronal alignment in Japan: a multicentric retrospective study of patients with knee osteoarthritis

Takashi Tsuda, JAPAN Kazunori Hino, MD, PhD, JAPAN Tatsuhiko Kutsuna, MD, PhD, JAPAN Kunihiko Watamori, MD, JAPAN Tomofumi Kinoshita, MD, PhD, JAPAN Takafumi Hiranaka, MD, PhD, JAPAN Eiichi Shiigi, MD、PhD, JAPAN Hiroshi Inui, MD, PhD, JAPAN Kohei Kawaguchi, MD, PhD, JAPAN Masaki Takao, Prof., JAPAN

Ehime University Graduate School of Medicine, Toon City, Ehime, JAPAN

2025 Congress   ePoster Presentation   2025 Congress   Not yet rated

 

Anatomic Location

Knee

Anatomic Structure

Bones

Diagnosis / Condition

Osteoarthritis Arthritis

Patient Populations

Elderly

Diagnosis Method

X-ray

Summary: Tibial medial joint tilt was primarily attributed to knee varus alignment, and progression of femoral lateral bowing was observed with age in the Japanese population.

Purpose

The distribution of individual femoral and tibial coronal alignments in patients with knee osteoarthritis in Japan remains poorly understood. This multicentric retrospective study investigated knee alignment in a Japanese population.

Methods

1525 knees that underwent total knee arthroplasty or unicompartmental knee arthroplasty for knee osteoarthritis in 4 institutions were evaluated. Preoperative hip-knee-ankle angle(HKA), mechanical lateral distal femoral angle (mLDFA), and medial posterior tibial angle (MPTA) were measured. The subjects were classified according to the coronal plane alignment of the knee (CPAK) classification (MacDessi et al. BJJ 2021). Femoral and tibial alignments were compared among the three groups divided by age (< 70 years old, 70-79 years old, and ≥ 80 years old).

Results

The mean HKA, LDFA, and MPTA were -8.9°±7.6°, 88.7°±3.1°, and 84.4°±3.2°, respectively, with further varus alignment of the MPTA compared with valgus alignment of the LDFA. The most common distribution, according to the CPAK classification, was type I (58.6%), followed by type II (18.8%). Patients aged ≥ 80 years had a significantly larger mLDFA than those aged < 70 and 70-80 years (89.2°±3.1° vs. 88.6°±3.0 °and 88.3°±3.1°; p=0.002 and <0.0001, respectively), whereas no significant difference was observed in MPTA.

Discussion

Our results showed a larger tibial medial tilt than that reported in a previous Western study (Almaawi et al. J arthroplasty 2017; the mean HKA, mLDFA, and MPTA were -0.1°, 87.3°, and 87.1°, respectively). Moreover, the results indicated that progression of femoral lateral bowing was observed with age. These findings suggest the effectiveness of adopting personalized alignment concept in the Japanese population when considering surgical strategies for knee arthroplasty.