OBJECTIVE: To evaluate the effects of a new periarticular injection in the patients with knee osteoarthritis. METHOD: Twenty seven patients, who had knee pain, were met criteria of knee osteoarthritis of American Rheumatology Association. Two injection sites were used: one to infrapatellar fat pad and the other to near the insertion area of popliteus. At first, 1 cc of 0.5% lidocaine was injected to both sites. If pain was not releaved above 50%, a mixture of 1 cc of 0.5% lidocaine and 10 mg of triamcinolone acetonide was injected to twenty seven patients, 46 knees. All patients were evaluated visual analogue scale (VAS), time for 10 meter walking, time for stair up and down, isometric knee strength before and after reatment. Paired student t test was done to investigate statistical significance of change of pain and function. RESULTS: Before treatment VAS, time for 10 meter walking, time for stair up and down and isometric knee strength were 6.1 +/- 2.1, 10.4 +/- 3.6, 10.8 +/- 7.1 and 34.0 +/- 11.4 respectively. After last treatment VAS, time for 10 meter walking, time for stair up and down and isometric knee strength were 3.5 +/- 2.5, 8.3 +/- 1.7, 8.2 +/- 3.6 and 38.8 12.9 respectively. The difference was stastistically significant between before and after treatment (p<0.05). CONCLUSION: The new periarticular injection is useful in treatment of patients with knee osteoarthritis.