Immediate effect of distal-approached orthotic interventions on women with bilateral medial compartment knee osteoarthritis

Abstract

Knee osteoarthritis (OA) is regarded as an epidemic in the middle-aged community. This disease is associated with aging and the deterioration of cartilages and bones, especially in the female population due to hormonal changes. Rapid aging of our general population and the increasing rate of obesity will increase the prevalent of knee OA cases and will pose a large impact to the healthcare system in the coming era. Since there is no known cure of knee OA nowadays, primary care of the patients is very important. Orthotic treatment is one of the conservative treatments to relieve symptomatic knee osteoarthritis and prevent further disease progression. The orthoses included knee braces, knee sleeves and knee unloading braces applied directly to the affected knee, and some orthoses applied indirectly, such as insoles and ankle-foot orthoses (AFO), which acted as a distal-approached orthotic management for knee osteoarthritis. Many studies had been conducted to investigate the effect of orthoses which were directly applied to the affected knee. However, there was a lack of study associated with distal-approached orthoses. Therefore, this study was carried out to investigate the immediate effect of distal-approached orthotic interventions on standing and walking in women with bilateral medial compartment knee OA. Bilateral medial compartment knee OA is the most common type of knee OA which causes alignment change to be knee varus. Moreover, since obesity is one of the risk factors leading to the progression of the OA knee, the effect of obesity on the static and dynamic results obtained was also studied by classifying the subjects into obese and normal weight groups. Western Ontario and McMaster universities (WOMAC) osteoarthritic knee index of the two groups was compared. Two distal-approached orthotic interventions were studied. They were custom-made lateral-wedged arch support and specially-designed AFO for OA knee. Subjects were assigned randomly in 4 different conditions for static and dynamic measurement and the results among the 4 conditions were compared. BTS P-walk system was used for data collection. The Statistical Package for Social Sciences software was used for data analysis. The study results showed that the immediate effect of the distal-approached orthoses on the averaged center of pressure movement speed on all subjects was significant. This implied that the distal-approached orthoses under investigation could immediately improve the postural stability of bilateral medial compartment OA knee subjects during standing, especially by the AFO. On the other hand, no significant immediate improvement was found on the gait of all OA knee subjects. Besides, obese group showed a significantly higher WOMAC score in physical functioning subscale which implied that obesity posed an adverse effect on the daily living of the OA knee patients. However, the effect of obesity on the quantitative measurement on static balance control and gait of the OA knee subjects was not significant.