Topical NSAIDs are more effective than placebo in treating the pain of OA, according to a systematic review.27 Also, few side effects were noted. A small randomized trial (n=70) of 0.025% capsaicin cream applied topically 4 times daily for 4 weeks reduced pain by 8% compared with placebo in patients with OA of the knee over a 4-week period.19 Further studies are needed to confirm this finding.
Complementary and Alternative Medicine
A recent meta-analysis found that glucosamine produces a modest to large improvement in pain relief and functional outcomes compared with placebo.40 A systematic review of controlled trials found that glucosamine performed equally well or better than NSAIDs.41 Most trials used a dose of 1500 mg glucosamine per day and addressed OA of the knee. The benefits may be overestimated because of the presence of publication bias. Because glucosamine is not regulated by the United States Food and Drug Administration, preparations and effectiveness may vary. However, it is very well tolerated and costs approximately $20 per month. Based on these results, glucosamine should be considered in the treatment of OA.
Although chondroitin has not been as well studied as glucosamine, a meta-analysis found evidence of effectiveness.40 Most studies used 800 to 1200 mg of chondroitin daily for OA of the knee. An added benefit of using both together has not been proved.
Another therapy supported by good-quality evidence is the use of avocado/soybean unsaponifiables. A systematic review of herbal therapy concluded that 300 mg daily of avocado/soybean unsaponifiables can provide long-term symptomatic relief, particularly for patients with chronic stable OA of the hip.42 It may also help patients reduce their intake of NSAIDs.
The most recent systematic review of acupuncture for OA of the knee concluded that real acupuncture is better than sham acupuncture in treating pain but not function.43 Four of the studies in the meta-analysis were of high quality, although none assessed the patient’s rating of global improvement. Acupuncture should be considered in the treatment of OA of the knee.
Less convincing therapies include therapeutic touch and electromagnetic fields. Therapeutic touch aims at manipulating a person’s energy system to bring the body system back into balance. A well-done single-blinded randomized trial compared therapeutic touch with mock therapeutic touch for OA of the knee.44 The treatment group had a statistically significant decrease in pain and improved function compared with the placebo group in most of the outcomes measured. However, the differences were small (0.5- to 1.4-point difference on a 10-point scale) and may not be clinically important. Further studies are needed to demonstrate a clinical impact and to help us know how to incorporate this into our practices. A small study of 27 patients compared pulsed electromagnetic fields (PEMF) and placebo for the treatment of OA of the knee. Although, this double-blind randomized trial showed a 31% reduction in overall pain compared with sham PEMF, larger studies are needed before widespread use of this therapy is warranted.19
Injections
Intra-articular steroids for OA of the knee have been recommended by the American College of Rheumatology when an effusion and local signs of inflammation are present.45 In 3 studies comparing steroid injections to placebo, 2 found that steroids were effective over 1 to 2 weeks, and 1 trial showed no difference. None of the trials showed any long-term benefit of steroid injections.46
A systematic review of injectable biologic agents (glycosaminoglycans, mostly hyaluronic acid) found that in 6 of the 8 randomized trials for OA of the knee they were superior to placebo.46 Treatment regimens varied, making it difficult to determine optimal duration of treatment and route of administration (intramuscular vs intra-articular). A comparison of hyaluronic acid injections with naproxen found that they were equally effective in improving pain relief and function, although the injections had fewer side effects.47 Dextrose in a 10% solution is another biologic agent used intra-articularly; however, a well-designed study found that it was no more effective than placebo for OA of the knee.48 Injectable glycosminoglycans, such as hyaluronic acid, are recommended in the treatment of OA of the knee, although the cost must be considered. The most effective regimen has not been determined.
Surgery
Surgery is reserved for patients with severe disease of the hip or knee that is not controlled by less invasive measures. Total hip arthroplasty has been shown to improve quality of life in patients with advanced hip OA.49 Also, a cost-effectiveness analysis showed that total hip arthroplasty can be cost-effective in improving quality-adjusted life expectancy in the short term and long term.50 Total joint arthroplasty for OA of the knee has shown similar benefits in pain relief and functional improvement.45,46 It is not surprising that OA of the hip and knee is the most common indication for elective total hip and knee arthroplasty in the United States.51