Objective
To evaluate the efficacy of intra-articular hyaluronic acid and steroid injection in osteoarthritis of the knee.

Method
Among 653 patients with osteoarthritis, 531 patients were participated in this study. They were divided to three groups; A, treated with hyaluronic acid 2.5 ml intra-articular injection once a week for 5 times; B, hyaluronic acid 2.5 ml once a week for 5 times with triamcinolone 20 mg once at the first time; C, only triamcinolone 20 mg at the first time. Before injection, X-ray with standing view were checked and divided according to Kellgren's grade of osteoarthritis. The amount of pain relief was assessed by pain rating score (PRS) and visual analogue scale (VAS) 1 week before and 1 month after the treatment.

Results
The degree of pain relief by PRS and VAS were all improved at 1 month after injection compared with pre-injection status (p＜0.001). Intra-articular hyaluronic acid injection was more effective in Kellgren's grade I, II than in III, IV in pain relief and hyaluronic acid with steroid injection was more effective in III, IV.

Conclusion
The results suggest that intra-articular hyaluronic acid injection would be effective for the treatment of patients with osteoarthritis.