The Impact of Intermittent Pain in Women with Osteoarthritis of the Knee on Biomechanics and Muscle Activation Patterns during Level Walking and Stair Descent

Abstract

Osteoarthritis of the knee (KOA) is a degenerative, incurable, and highly debilitating disease. Among those experiencing KOA symptoms, most diagnoses are female. Of the symptoms associated with KOA, none are more detrimental than pain. Existing evidence has established that chronic pain results in irregular muscle activity above and below the knee during activity. This phenomenon, in turn, leads to abnormal joint loading and substantial alterations in gait patterns. However, the understanding of the effects of intermittent pain remains limited. Therefore, the primary objective of study one was to evaluate the impact of intermittent pain on muscle activity above and below the knee during walking and stepdown tasks in women with KOA (n = 7), compared to controls (n = 10). Study two aimed to investigate the influence of intermittent pain on gait parameters, and foot pressure distribution during walking and stepdown tasks among women with KOA (n = 7) compared to controls (n = 10). The findings from study one revealed that intermittent pain significantly altered mean and mean peak muscle activity, in the semitendinosus of the pain group, during the load acceptance phase of a stepdown task. There was no discernible influence of intermittent pain on muscle activity during walking. Study two revealed that there was no significant impact of intermittent pain on gait parameters and foot pressure distribution. Essentially, intermittent pain altered muscle activity, without significantly altering participants' walking patterns or the way force was distributed across the foot. In conclusion, intermittent pain primarily affects muscle activity rather than walking patterns or force distribution. Consideration of additional controls such as disease severity, foot arch height, fitness level, and motion analysis assessment might provide more insights. Given the significance impact of pain, future researchers should incorporate these controls, and others, to precisely investigate the effects of intermittent pain.