To analyze the improvement in the patient self-evaluation for shoulder function and range of motion after arthroscopic subacromial decompression for shoulder impingement syndrome.

We performed a study of 21 patients out of 45 patients who could be assessed preoperatively and at 6 weeks and 3, 6, 9 and 12 months, using the standardized method of Research Committee of American Shoulder & Elbow Surgeons. We used two-sample unequal variance student t-test and Mann-Whitney U test to compare the initial findings.

Nineteen patients were satisfied subjectively at 12 months after operation. Pain improvement was significant at 6 weeks. The total score of patient self-evaluation, put on a coat and manage using the toilet improved at 3 months, while sleep on painful side, wash back, comb hair, reach a high shelf and lift 5 kg above the shoulder improved at 6 months. Throwing a ball overhead improved at 9 months. The gain in range of motion was not noticeable except for internal rotation, which improved from T11 to T8.

We found an arthroscopic subacromial decompression to be an effective method for treating impingement syndrome of the shoulder. Functional recovery could improve during a prolonged period despite of early relief of pain.