Introduction: Osteoarthritis of the knee is a chronic degenerative disease in which the articular cartilage is worn away and gradually lost, other surrounding structures can also be affected. It is one of the main causes of pain and functional disability in older adults. The disease process is characterised by reduced muscle strength in various muscle groups, which in turn can affect the biomechanics of the knee joint itself. By strengthening the muscles, we aim to improve the absorption of the loads acting on the joint and thus lead to better protection of the cartilage. Purpose: To present the effects of hip muscle strengthening on pain and functional capacity in people with osteoarthritis of the knee, based on a review of the literature. Methods: The literature was searched in PEDro and EBSCO databases based on the keywords knee osteoarthritis AND hip strengthening; knee osteoarthritis AND hip abductor; knee osteoarthritis AND hip muscle strengthening. Results: We analysed seven studies. The exercise programs mainly focused on strengthening the hip abductors and adductors in combination with strengthening the quadriceps femoris. Progressive resistance exercise performed at least two to three times a week, in two to four sets of eight to twelve repetitions, and at an intensity of 50-70 % 1 RM, had a positive short-term effect on pain reduction (p < 0,05) in subjects with osteoarthritis of the knee. Two studies measured long-term effects, one six weeks and the other six months after the interventions and found that the positive effects on pain had disappeared. Statistically significant differences were also present in the measured functional status outcomes, with better results in the group that strengthened the hip muscles in addition to strengthening the quadriceps femoris. Discussion and conclusion: Based on the results of the studies, it can be concluded that progressive resistance training to strengthen the hip muscles, especially the abductors, in combination with strengthening of the quadriceps femoris, has positive effects on pain, functional ability and quality of life in people with knee OA. Strengthening of the hip adductors could also have positive effects on pain and functional ability in people with knee OA, but this is an area that should be further investigated. To facilitate comparison of results in the future, it would be necessary to use the same assessment protocols and more uniform exercise programs, and it would be reasonable to use larger samples of subjects.
|