Ultrasound in the management of osteoarthritis: part I: a review of the current literature.

BACKGROUND Ultrasound has been widely used in clinical settings for the management of various ailments but many authors still question its efficacy. An accumulating body of literature demonstrates that ultrasound evokes a broad spectrum of bioeffects which may be therapeutically beneficial in the management of a variety of clinical conditions. OBJECTIVE A critical review the current research investigating the use of therapeutic ultrasound in the treatment and/or management of osteoarthritis. Specific emphasis is placed on interpreting the literature in the context of its strengths and weaknesses, with particular attention placed on study protocols and technical parameters used in the trials. Relevant basic science is also introduced and meaningful inter-study comparisons are highlighted with suggestions for future research. DESIGN Literature Review. METHODS A Pubmed search of the literature was performed from 1985 to present using the key words "ultrasound" and "osteoarthritis" retrieved a total of 313 publications. Experimental, clinical and animal studies that directly assessed applications of therapeutic ultrasound in the clinical management of osteoarthritis and/or its underlying physiologic mechanisms were accepted. Studies that evaluated ultrasound in combination with other modalities were accepted but their conclusions were interpreted in the context of their methodological strengths and limitations. RESULTS A total of 17 articles met our search criteria; one study was excluded due to poor methodology. Of a total of five review papers, two concluded that ultrasound had positive therapeutic effects, two did not demonstrate any benefit and one was inconclusive. The remaining nine studies consistently reported that ultrasound has therapeutically beneficial effects on pain and functional outcomes. Five studies reported that ultrasound has positive cartilage healing properties and one experimental study demonstrated increased intra-articular absorption of high molecular weight molecules (hyaluronan) using ultrasound phonophoresis. Only one randomized controlled trial reported no effect on pain or active range of motion when ultrasound is used in combination with exercise. CONCLUSIONS Ultrasound demonstrates the ability to evoke a broad range of therapeutically beneficial effects which may provide safe and effective applications in the management of osteoarthritis.