To evaluate the efficacy and safety of injection of high molecular weight (HMW) hyaluronan (Orthovisc) in patients with mild, moderate, and severe knee osteoarthritis (OA).
A randomized, arthrocentesis-controlled, multicenter trial. Patients (n = 372) were randomized to 4 weekly HMW hyaluronan injections (O4, n = 128), 3 weekly HMW hyaluronan injections followed by one arthrocentesis (O3A1, n = 120), or 4 arthrocenteses without injection (control group, A4, n = 124). All patients had knee OA, as determined by Kellgren-Lawrence (K-L) grade, and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) pain score > or = 200 mm and < 400 mm in index knee and < 150 mm in contralateral knee. The primary outcome measure was the proportion of patients achieving a 20% relative and 50 mm absolute improvement from baseline in WOMAC pain score at Weeks 8, 12, 16, and 22 post-baseline in the index knee. Secondary outcomes were Patient Global score, Investigator Global score, and Pain on Standing score.
The evaluable subgroup consisted of patients with K-L grade 2 or 3 at baseline. The comparison of O4 versus A4 for the primary outcome approached, but did not reach, significance in the evaluable subgroup: 76% of O4 patients had > or = 20% improvement in WOMAC pain score at Week 8 compared to 62% of A4 patients. More O4 patients had > or = 40% improvement in WOMAC pain score compared to A4. The effectiveness of the 3-injection regimen (O3A1) was masked by a possible placebo effect from the needle injection procedure in the A4 (control) group. No differences between groups were observed with respect to incidence of adverse events.
Our findings indicate that HMW hyaluronan is safe and seems to be effective in the treatment of mild to severe OA of the knee.