Early recovery of isometric shoulder muscle strength after open acromioplasty in stage II impingement syndrome

The recovery of shoulder muscle strength after open acromioplasty was evalu ated in 48 patients (27 male, 21 female, mean age 44.3 years) who had under gone open acromioplasty because of stage II impingement syndrome. The isome tric strengths of flexion, abduction and external rotation were measured be fore the operation and at 3, 6 and 12 months postoperatively. The mean preo perative flexion strength of the involved shoulder was 72.6% of that of the uninvolved shoulder, and this increased to 77.1% by 3 months post operatio n, to 88.3% at 6 and to 88.3% at 12 months. Corresponding abduction strengt hs were 68.4%, 80.4%, 88.7% and 91.0% and the external rotation strengths w ere 75.1%, 77.4%, 95.1% and 93.5%, respectively. These recoveries were mark edly improved when the cases with poor subjective results at 1 year were no t considered. The low preoperative strengths were more pronounced in women than in men, but recovery was better in women. It is concluded that shoulde r muscle strengths recover to near normal in 1 year after open acromioplast y.