Effects of Isometric Strengthening Exercises on Pain and Disability Among Patients With Knee Osteoarthritis

Introduction Osteoarthritis (OA) is the most common form of arthritic disease of the joint worldwide, with the knee joint being the most affected in the body. This study investigated the effects of isometric strengthening exercises on pain and disability among patients with knee osteoarthritis. Methods This randomized control trial research design was carried out at the Physiotherapy Departments of Nnamdi Azikiwe University Teaching Hospital, Nnewi, and Chukwuemeka Odumegwu Ojukwu University Teaching Hospital, Amaku, Awka in Anambra State, Nigeria. A total of 40 subjects, nine (22.5%) males and 31 (75.5%) females, were randomly assigned into exercise and control groups. Prior to intervention, the weight and height of each subject were measured. Pain intensity, active range of motion (AROM) and passive range of motion (PROM), and functional ability of both groups were recorded using the Numerical Pain Rating Scale (NPRS), universal goniometer, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), respectively. All participants in the exercise group performed isometric quadriceps and straight leg raise exercises, and the control group received no intervention whatsoever. After six weeks, the pain intensity, AROM, PROM, and functional ability scores were re-measured and documented. Results While comparing the pre-test and post-test scores using paired t-test, the exercise group showed a significant difference in each parameter (NPRS, AROM, PROM, and WOMAC = 0.000), while the control group showed no significant difference. Independent sample t-test outcome at six weeks (exercise and control groups) showed significant reduction of pain intensity (NPRS = 0.000), increased range of motion (AROM = 0.000, PROM = 0.003), as well as improvement in function (WOMAC = 0.000) at a significant level of p < 0.05. Conclusion At the end of the six weeks, isometric strengthening exercises showed a significant effect on pain intensity, range of motion, and functional ability among subjects with knee osteoarthritis.