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Updated: Oct 10, 2026
Treatment of Ankle Osteoarthritis with Total Ankle Replacement Through a Lateral Transfibular Approach
Published on: January 24, 2018
Personalized alignment correction targets based on osteoarthritis progression achieve sufficient lateral load
Yugo Morita1, Shinichi Kuriyama1, Yusuke Yamawaki2
1Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Background:
Open-wedge high tibial osteotomy (OWHTO) shifts medial loading laterally, but postoperative redistribution varies. Patient-specific finite element analysis (FEA) quantified load redistribution and associated factors.
Methods:
Forty knees in 34 patients with medial compartment osteoarthritis were analyzed (Kellgren-Lawrence [KL] grades ≤2, 18; 3, 16; 4, 6). Surgical planning uniformly targeted a percentage mechanical axis (%MA) of 60.0%-62.5%. Patient-specific FEA models incorporating knee-specific geometry, alignment, joint morphology, and computed tomography (CT)-density-based bone properties were constructed from preoperative and 1-year post-implant-removal CT for pre- and postoperative standing simulations, respectively. Postoperative CT (1-2 weeks) measured opening width. FEA yielded contact forces and lateral-to-total ratios. Associations with postoperative %MA, opening width, and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales were examined. Receiver operating characteristic (ROC) and KL-stratified regression analyses explored reference values for lateral-to-total ratio ≥50% (equal compartmental force sharing).
Results:
Radiographic %MA increased from 17.2% to 57.9%. FEA-derived medial contact force decreased from 415.4 to 320.9 N, lateral contact force increased from 157.1 to 268.6 N, and lateral-to-total ratio increased from 27.9% to 45.8% (all P < 0.001), without increasing peak lateral stress. Postoperative %MA correlated with lateral transfer; larger opening width, reflecting required correction rather than a causal effect, was associated with reduced transfer. Lateral contact force correlated with KOOS Symptoms and Activities of Daily Living. ROC analysis identified a postoperative %MA of 59.4% and an opening width of 9.5 mm as exploratory reference values. Estimated %MA for ratio ≥50% was 60.5%, 63.0%, and 68.8% for KL grades ≤2, 3, and 4, respectively.
Conclusions:
OWHTO shifted tibiofemoral loading laterally without increasing peak lateral stress. A higher postoperative %MA was associated with greater lateral transfer. Opening width should be considered a marker of required correction rather than a causal determinant; alignment targets may warrant individualized consideration in advanced osteoarthritis.