RESUMEN
BACKGROUND: Many middle-aged and older adults participate in running to maintain their health and fitness; however, some have to stop running due to osteoarthritis-attributed knee pain. It was unclear whether gait biomechanics and knee physical findings differ between those who can and cannot run. RESEARCH QUESTION: What are the gait and knee physical findings of patients with knee osteoarthritis who remain capable of running in comparison to those who are not capable of running? METHODS: This was a cross-sectional study, which recruited 23 patients over the age of 40 who had been diagnosed with knee osteoarthritis. Their knee joint ranges of motion and muscle strength, knee pain, and the maximum gait speed (walk as fast as possible) were measured. Knee alignment was calculated from X-ray images, and the knee joint extension angle and adduction moment during a self-selected gait speed were determined using motion analysis. Participants were divided into two groups-those able to run (n=11) and those unable to run (n=12). The measured and calculated outcomes were compared between groups, and logistic regression analyses of significantly different outcomes were performed. RESULTS: There were significant group differences in the maximum knee extension angle during stance phase (p = 0.027), maximum gait speed during the 10-m walk test (p = 0.014), knee pain during gait (p = 0.039) and medial proximal tibial angle by X-ray (p = 0.035). Logistic regression analyses revealed that the maximum knee extension angle during stance phase (OR: 1.44, 95%CI: 1.06¬1.94, p = 0.02) was a significant factor. SIGNIFICANCE: The ability to extend the knee during gait is an important contributing factor in whether participants with knee osteoarthritis are capable of running.
