Objective: To evaluate viscosupplementation by intraarticular injection of Orthovisc® Vs. Synvisc® (Molecular Weight 1.55 and 6 Million Daltons, respectively) in the treatment of knee osteoarthritis in clinical practice in Israel.
Methods: We performed a prospective evaluation of all patients treated with either Orthovisc® or Synvisc® by the senior author during a 2 year period. All patients suitable for hyaluronic acid injections were included in the study. Patients bought either product at their own expense and preference.
A total of 1566 injections were performed involving 522 knees. Patients were divided into two groups; one consisting of 277 patients who purchased Orthovisc® and a second consisting of 245 patients who purchased Synvisc®.
A Visual Analog Scale (VAS) assessed pain. The senior author performed all injections and sterile injection protocol was strictly adhered to.
Knees were injected at weekly intervals for 3 weeks. Patients were assessed at baseline, 1, 2, 3 &
4 weeks and 3, 6 &
12 months following initial visit.
Results: Both products were found to be of clinical benefit and have an acceptable safety profile. No difference in VAS values was found between the two groups. The calculated Power of Study for detection of a one-pain unit difference was 99.9% (α=0.05). This power was maintained through the first three visits and later declined.
Conclusion Our findings question the impact of hyaluronic acid molecular weight in alleviating osteoarthritic knee pain.