The effectiveness and safety of intra-articular injection of sodium hyaluronate (500-730 kDa) in the treatment of patients with painful knee osteoarthritis.

Background: Sodium Hyaluronate (500-730 kilodalton (kDa); Hyalgan) is recommended to administer intra-articularly once a week for 3-5 weeks in patients with osteoarthritis of the knee which its efficacy has been shown, from many clinical studies, to persist for at least 6 months. However only a few studies were done in Thai patients.

Objective: To assess the efficacy and safety of intra-articular Sodium Hyaluronate, administered once a week for four weeks (four injections) in Thai patients with painful Tibio-Femoral osteoarthritis of the knee over a six-month period.

Material And Method: Thirty-one patients with painful knee osteoarthritis in grade I (32.3%) and grade II (67.7%) severity on Ahlback radiological criteria from Orthopedic Clinic in Bhumibol Adulyadej Hospital were included in this study. All patients were administered with 4-weekly injections of intra-articular Sodium Hyaluronate (500-730 kDa; Hyalgan; 20mg/2ml). Only paracetamol was permitted for escape analgesia. The efficacy parameters were the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) for pain, stiffness and physical function, intake of paracetamol, and overall efficacy judgment by investigators and patients. The occurrence of adverse event was recorded at each visit.

Results: After the second injection of Sodium Hyaluronate, all WOMAC index revealed the significant improvement from baseline (p < 0.05). The WOMAC-VAS for pain at baseline, Day 14, 28, 84, and 168 were 50.3, 33.3, 29.1, 23.1, and 21.4 mm respectively. At the end of study, most patients and investigators evaluated treatment efficacy as moderate to very effective. There was a decrease in paracetamol consumption from baseline until the last follow-up. Nine adverse events were recorded, which were transient events; most of them consisted of pain at injection site. No systemic or serious adverse event was reported.

Conclusion: The results of this study showed the efficacy and safety of 4-weekly injections of Sodium Hyaluronate in the treatment of knee osteoarthritis in Thai patients over a six-month period.