Igura Reo, Nakamura Jun, Anan Masaya
Clinical Practice and Support, Division of Rehabilitation, Hiroshima University Hospital, Hiroshima, JPN.
Physical Therapy, Faculty of Welfare and Health Science, Oita University, Oita, JPN.
Cureus. 2025 Aug 14;17(8):e90117. doi: 10.7759/cureus.90117. eCollection 2025 Aug.
Background and Objectives: According to the well-established correlation between knee joint contact force and external knee adduction moment (KAM) during walking, many studies have focused on gait modifications that target changes in the frontal plane, such as foot progression and trunk inclination angles, to decrease KAM. However, recent research has highlighted the relationship between the external knee flexion moment (KFM) and knee joint contact force, highlighting the importance of considering both the KAM and KFM in gait modifications that highlight changes in the sagittal plane. Consequently, the current study aimed to investigate the effects of increasing knee joint flexion angle while walking on knee joint loading.
This study was a cross-sectional study. 20 healthy older adults each performed two gait conditions - normal walking and walking with a 10-degree increase in the maximum flexion angle, with five trials conducted for each condition.
The results showed that increasing the flexion angle significantly reduced KAM. Specifically, the first peak KAM decreased from 0.59 ± 0.24 to 0.43 ± 0.26 N·m/kg·m (p < 0.001), and the second peak KAM from 0.57 ± 0.20 to 0.45 ± 0.25 N·m/kg·m (p = 0.002). Conversely, the peak KFM increased significantly from 1.5 ± 0.48 to 1.8 ± 0.51 N·m/kg·m (p < 0.001). Furthermore, gait modification involved a straightforward intervention-merely providing verbal instructions to slightly increase knee flexion angle-making it both feasible and practical for older adults at higher risk of developing osteoarthritis of the knee (knee OA).
Ensuring sufficient knee joint flexion angle during the early stance phase may serve as an effective instructional strategy for reducing KAM. Given its simplicity and non-invasive nature, this intervention may have practical potential for use in clinical or community-based gait training programs for older adults at risk of knee OA. However, these findings should be interpreted with caution when generalized to patients with knee OA. Such individuals may have altered muscle activation, increased joint sensitivity, or limited range of motion, which could affect their response to gait modification. Future studies involving longitudinal follow-up or patient-centered outcomes such as pain, function, and adherence will be necessary to evaluate the long-term clinical applicability of this intervention.
背景与目的：根据步行过程中膝关节接触力与膝关节外展力矩（KAM）之间已确立的相关性，许多研究聚焦于针对额状面变化的步态修正，如足部前进和躯干倾斜角度，以降低KAM。然而，近期研究突出了膝关节外展力矩（KFM）与膝关节接触力之间的关系，强调在突出矢状面变化的步态修正中同时考虑KAM和KFM的重要性。因此，本研究旨在探讨步行时增加膝关节屈曲角度对膝关节负荷的影响。
本研究为横断面研究。20名健康老年人分别进行两种步态条件——正常步行和最大屈曲角度增加10度的步行，每种条件进行5次试验。
结果表明，增加屈曲角度显著降低了KAM。具体而言，第一个峰值KAM从0.59±0.24降至0.43±0.26 N·m/kg·m（p<0.001），第二个峰值KAM从0.57±0.20降至0.45±0.25 N·m/kg·m（p = 0.002）。相反，峰值KFM从1.5±0.48显著增加至1.8±0.51 N·m/kg·m（p<0.001）。此外，步态修正涉及一种简单的干预——仅提供口头指示以略微增加膝关节屈曲角度——这使其对患膝关节骨关节炎（膝OA）风险较高的老年人既可行又实用。
在早期站立阶段确保足够的膝关节屈曲角度可能是降低KAM的有效指导策略。鉴于其简单性和非侵入性，这种干预在针对有膝OA风险的老年人的临床或社区步态训练计划中可能具有实际应用潜力。然而，当推广到膝OA患者时，这些发现应谨慎解释。此类个体可能存在肌肉激活改变、关节敏感性增加或运动范围受限，这可能影响他们对步态修正的反应。未来需要进行涉及纵向随访或以患者为中心的结果（如疼痛、功能和依从性）的研究，以评估这种干预的长期临床适用性。
