Hyaluronic Acid Injections or Oral Nonsteroidal Anti-inflammatory Drugs for Knee Osteoarthritis: Systematic Review and Meta-analysis of Randomized Trials

BACKGROUND: Intra-articular hyaluronic acid (HA) injections and oral nonsteroidal anti-inflammatory drugs (NSAIDs) are common treatments for symptomatic knee osteoarthritis (OA). However, the comparative effects of these treatments are unclear. PURPOSE: To compare the efficacy and safety of intra-articular HA injections compared with oral NSAIDs for the treatment of knee OA. STUDY DESIGN: Systematic review; Level of evidence, 1. METHODS: We systematically searched Medline, Embase, and the Cochrane Central Register of Controlled Trials for randomized trials of knee OA treatment with HA injections compared with oral NSAIDs. The main outcomes were knee pain, knee function, adverse events (AEs), serious AEs, study withdrawals, and study withdrawals because of AEs. Pooled effect sizes were reported at the final follow-up with standardized mean difference (SMD) for efficacy outcomes and risk ratio (RR) for safety outcomes. RESULTS: In 6 randomized trials of 831 patients (414 HA, 417 NSAIDs), with follow-up ranging from 5 to 26 weeks, HA injections were associated with small, statistically significant improvements in knee pain (SMD, 0.15; P = .04) and knee function (SMD, 0.23; P = .01) compared with oral NSAIDs. The risk of AEs was lower with HA compared with NSAIDs (19.8% vs 29.0%; RR, 0.74; P = .01). The risk of a serious AE (RR, 1.37; P = .71), study withdrawal (RR, 1.05; P = .68), or study withdrawal because of an AE (RR, 0.65; P = .22) was comparable between groups. Gastrointestinal concerns were the most frequent AE reported, occurring more often with NSAIDs (23.4% vs 14.1%; P = .001). AEs reported more frequently with HA injections were injection site pain (11.7% vs 4.7%; P < .001), headache (8.4% vs 4.4%; P = .03), and arthralgia (8.1% vs 2.9%; P = .001). Significant heterogeneity or publication bias was not observed for any outcome. CONCLUSION: Comparing short-term outcomes of HA injections with oral NSAIDs for treatment of knee OA, HA injections provided statistically significant but not clinically important improvements in knee pain and function, along with a lower overall risk of AEs.