Nonsurgical treatments for knee arthritis include several types of intra-articular injections. Although studies of corticosteroid and hyaluronic acid injections have had mixed results, a number have demonstrated some efficacy for these injections in relieving pain and improving function in patients with osteoarthritis. Comparison studies have been limited because of small populations and potential bias from the funding source. Leopold and associates conducted a prospective, blinded, randomized study to compare the efficacy of intra-articular injections of betamethasone sodium phosphate–betamethasone acetate and hyaluronic acid in patients with knee osteoarthritis.
The authors enrolled 100 patients with radiologic confirmation of symptomatic knee osteoarthritis who had not received an intra-articular injection in the past three months. To qualify for the study, the patients had to have no clear evidence of chondrocalcinosis or ligament insufficiency, and no history of inflammatory arthritis, crystalline arthropathy, or neuropathic arthropathy. Participants were randomized to receive one course of three weekly injections of hyaluronic acid or a single 2-mL injection of the corticosteroid solution with an anesthetic. Patients receiving the corticosteroid preparation could request a second injection during the study period, if needed.
Although pain and function improved in both treatment groups, no significant differences were noted between the two groups at three or six months. Rates of withdrawal from the trial and adverse effects from the injection were similar in both groups.
The authors conclude that intra-articular injections of hyaluronic acid or corticosteroids provide similar modest improvement of function in patients with osteoarthritis of the knee. Because hyaluronic acid is more expensive and requires three separate injections, the authors note that it probably is not an appropriate first-line treatment for patients with symptoms of knee osteoarthritis who are considering intra-articular injections.