NEW YORK (Reuters Health) – A single 6-mL intra-articular injection of hylan G-F 20 (Synvisc-One, Genzyme Biosurgery) safely reduces knee osteoarthritis pain for 26 weeks, results of a prospective European trial suggest.

Lead researcher Dr. Xavier Chevalier and associates explain in the January issue of the Annals of the Rheumatic Disease that injections of hyaluronic acid, or its derivatives, are given to patients with knee osteoarthritis because their synovial fluid levels of HA are reduced. In the past, the HA product hylan G-F 20 has been administered in three 2-mL injections at weekly intervals. For the current study, the researchers studied safety and efficacy of administering the total dose at one time.

Patients with primary knee osteoarthritis who were undergoing arthrocentesis were randomized to receive a 6-mL intra-articular injection of either hylan G-F 20 (n = 124) or placebo (n = 129).

Patients were evaluated at 4, 8, 12, 18, and 26 weeks post-injection. For 48 hours before study visits, they abstained from medications for pain or osteoarthritis.

Dr. Chevalier, from Hopital Henri Mondor in Creteil, France, and colleagues report that at 26 weeks, pain as measured by the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index A had improved by an average of 36% in the hylan G-F 20 group and 29% in the placebo group (p = 0.047).

There were significant differences for secondary outcome measures as well, including pain while walking. For example, at 18 weeks, 71% of patients in the hylan G-F 20 group and 53% in the placebo group were