Objective
To assess the level of scientific evidence and the place in the rehabilitation framework of isokinetic muscle strengthening (IMS) for knee osteoarthritis (OA).
Methods
A systematic review of the English literature in MEDLINE via PubMed, the Cochrane Library, and PEDro databases for only randomized comparative trials. Data that were sufficiently homogeneous underwent comprehensive meta-analysis. Methodological assessment was done by using the CLEAR scale for non-pharmacologic trials.
Results
We identified articles for 9 trials (696 patients). All trials were of low to moderate quality. Tolerance of IMS was considered good. Improvement in muscle strength was better with an IMS program than no treatment or an isometric exercise but did not differ with an aerobic program. We found an important effect for pain (standardized mean difference 1.218 [95% CI 0.899-1.54], P<0.001) and functional Lequesne index (1.61 [0.40-2.81], P=0.009) and a moderate effect for the Western Ontario and McMaster Universities Osteoarthritis Index subscore C for disability (0.58 [0.04-1.11], P=0.03).
Conclusions
IMS is an effective way to propose dynamic muscle strengthening for knee OA rehabilitation and has a significant effect on pain and disability. Because of the weak methodology and the great heterogeneity of studies, particularly in IMS protocol and outcome measures, insufficient data are available to provide guidelines about efficacy and strategy. Future clinical trials are needed, but more attention should be paid to the methods of such studies to clarify the role of IMS in the therapeutic armamentarium of knee OA.