THE ARTHROSCOPIC IMPINGEMENT TEST

Arthroscopic acromioplasty is an effective technique to treat refracto ry impingement syndrome of the shoulder; however, it is a technically demanding procedure and failure due to inadequate acromial resection h as been reported. The purpose of this study was to describe a more rel iable technique of arthroscopic acromioplasty (''arthroscopic impingem ent test'') that allows determination of subacromial space available ( SSA) during shoulder flexion after acromioplasty. During a 2-year peri od, 70 consecutive patients (group I) underwent arthroscopic acromiopl asty by a conventional technique and 50 consecutive patients (group II ) underwent the modified technique. Both groups were comparable in ter ms of age, gender, chronicity of symptoms, incidence of workman's comp ensation cases, side of surgery, and operative findings. In group I, f our patients (6%) failed due to inadequate acromioplasty and at time o f revision were found to have 0 mm SSA at 120-degrees flexion (contact of cuff on acromion). After revision acromioplasty, SSA at 120-degree s flexion was measured as > 3 mm, and impingement symptoms resolved po stoperatively. In group II, there were no failures and SSA after initi al acromioplasty was found to average 13 mm at 0-degree, 10 mm at 45-d egrees, 8 mm at 90-degrees, and 6 mm at 120-degrees flexion. In four c ases, 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 wa s concluded that the ''arthroscopic impingement test'' improves reliab ility of arthroscopic acromioplasty by verifying adequate acromial res ection in a position of impingement.