Efficacy and Safety of Hylan versus Hyaluronic Acid in the Treatment of Knee Osteoarthritis.

The purpose of this study was to use meta-analytic approach to compare the efficacy and safety of intraarticular hylan and hyaluronic acid (HA) for knee osteoarthritis (OA) treatment. We searched PubMed, Embase, and the Cochrane databases through July 2017 to identify Level I randomized controlled trials (RCTs) that evaluated clinical efficacy and safety of hylan compared with HA for knee OA. The primary outcomes were Visual Analogue Scale (VAS) for pain and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, and WOMAC function scores. In each study and for the outcome measures (VAS for pain, WOMAC pain, function and stiffness scores, and Lequesne score), we calculated the treatment effect from the difference between the preintervention and postintervention changes in the hylan and HA groups. Twenty-one RCTs involving 3,058 patients were included. Pooled analysis suggested that compared with HA, hylan was associated with similar pain relief and function improvement in patients with knee OA (VAS for pain: mean difference [MD], -3.04; 95% confidence interval [CI], -9.13 to 3.04; p  = 0.33; I 2  = 76%. WOMAC pain score: MD, 0.23; 95% CI, -0.25 to 0.70; p  = 0.35; I 2  = 0%. WOMAC function score: MD, -0.47; 95% CI, -6.81 to 5.88; p  = 0.88; I 2  = 84%). No significant difference was found comparing the patients with treatment-related adverse events. The relationship was robust in sensitivity analysis and consistent in most of the subgroup analyses. As to the primary outcomes (WOMAC pain, function scores, VAS for pain), the difference between hylan and HA did not reach the previously reported minimum clinically important difference (MCID) values (-13.4 for VAS for pain, -2.0 for WOMAC pain score, -7.7 for WOMAC function score). Our meta-analysis showed that there were no statistically and clinically significant differences in pain relief and function improvement between hylan and HA injections for knee OA treatment. In view of its higher costs, we discourage the use of hylan in patients with knee OA in clinical practice. The level of evidence is I, meta-analysis of Level I studies.