Biomechanical effects of a semi-rigid knee orthotic during walking in individuals with medial knee osteoarthritis
Year: 2026
Type: article
Study design: Clinical Trial
Abstract: BACKGROUND: Medial knee osteoarthritis is associated with increased medial compartment loading during gait. Valgus unloader knee orthotics are commonly used to reduce medial knee loading, but the biomechanical responses associated with semi-rigid designs remain unclear. RESEARCH QUESTION: After six weeks of use, what effect does the orthotic condition have on first-peak knee adduction moment (KAM), second-peak KAM, and knee adduction angular impulse (KAAI) during constant-speed and self-selected-speed walking compared with baseline in individuals with medial knee osteoarthritis? METHODS: Twenty-four participants with Kellgren-Lawrence grade 2-4 completed a within-participant pretest-posttest study. Gait was assessed without the orthotic at baseline and while wearing it after six weeks of use (mean 5.13 h/day), at a constant speed of 1.39 m/s and self-selected speed. In OpenSim, first-peak KAM, second-peak KAM, and KAAI were calculated. GRF variables were secondary, exploratory outcomes. Conditions were compared using paired t-tests or Wilcoxon signed-rank tests. Holm-Bonferroni adjustment was applied to the three KAM-related outcomes within each walking condition. RESULTS: During constant-speed walking, first-peak KAM, second-peak KAM, and KAAI were lower with the orthotic by 6.9% , (r = 0.44), 6.8% (r = 0.47), and 15.8% (r = 0.51), respectively (Holm-adjusted p = 0.045 for each). Vertical GRF variables did not differ, whereas the braking-peak magnitude and braking and propulsive impulses increased. During self-selected-speed, participants walked 15.5% faster in the orthotic condition (p < 0.001). First- and second-peak KAM did not differ significantly from baseline, whereas KAAI was lower (-0.030 N·m·kg⁻¹·s, 95% CI -0.050 to -0.010; Holm-adjusted p = 0.014). The first vertical, braking, and propulsive GRF peaks increased, while vertical impulse decreased. SIGNIFICANCE: Semi-rigid orthotic use was associated with lower KAM-related loading during constant-speed walking and faster self-selected walking without higher peak KAM. The semi-rigid orthotic may be considered a possible adjunct to individualized, multicomponent care for individuals with medial knee osteoarthritis.
Source: Gait & Posture
Institution: Karlsruhe Institute of Technology
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,510
OpenAlex ID: W7225087563