The "arthroscopic impingement test".

Arthroscopic acromioplasty is an effective technique to treat refractory impingement syndrome of the shoulder; however, it is a technically demanding procedure and failure due to inadequate acromial resection has been reported. The purpose of this study was to describe a more reliable technique of arthroscopic acromioplasty ("arthroscopic impingement test") that allows determination of subacromial space available (SSA) during shoulder flexion after acromioplasty. During a 2-year period, 70 consecutive patients (group I) underwent arthroscopic acromioplasty by a conventional technique and 50 consecutive patients (group II) underwent the modified technique. Both groups were comparable in terms of age, gender, chronicity of symptoms, incidence of workman's compensation cases, side of surgery, and operative findings. In group I, four patients (6%) failed due to inadequate acromioplasty and at time of revision were found to have 0 mm SSA at 120 degrees flexion (contact of cuff on acromion). After revision acromioplasty, SSA at 120 degrees flexion was measured as > 3 mm, and impingement symptoms resolved postoperatively. In group II, there were no failures and SSA after initial acromioplasty was found to average 13 mm at 0 degree 10 mm at 45 degrees, 8 mm at 90 degrees, and 6 mm at 120 degrees flexion. In four cases, the "arthroscopic impingement test" determined that there was inadequate SSA at 120 degrees (< 3 mm) after initial acromioplasty, and these were revised by further acromioplasty at time of surgery. It was concluded that the "arthroscopic impingement test" improves reliability of arthroscopic acromioplasty by verifying adequate acromial resection in a position of impingement.