Contact pressure and glenohumeral translation following subacromial decompression: how much is enough?

Subacromial decompression is a common surgical procedure that has historically included coracoacromial ligament resection. However, recent reports have advocated preserving the coracoacromial ligament to avoid the potential complication of anterosuperior escape. The optimal subacromial decompression would achieve a smooth coracoacromial arch and decreased rotator cuff contact pressures while preserving the function of the arch in glenohumeral stability. We hypothesized that a subacromial decompression with a limited acromioplasty with preservation of the coracoacromial ligament can decrease extrinsic pressure on the rotator cuff similar to a coracoacromial ligament resection, without altering glenohumeral translation. Three different subacromial decompressions, including a "smooth and move," a limited acromioplasty with coracoacromial ligament preservation, and a coracoacromial ligament resection, were performed on 6 cadaveric specimens with intact rotator cuffs. Glenohumeral translation and peak rotator cuff pressure during abduction were recorded. No change in translation was observed after a smooth and move or a limited acromioplasty. Compared to baseline specimens, anterosuperior translation was increased at 30° of abduction following coracoacromial ligament resection (P<.05). Baseline rotator cuff pressure was greatest during abduction with the arm in 30° of internal rotation. Peak rotator cuff pressure decreased up to 32% following a smooth and move, up to 64% following a limited acromioplasty, and up to 72% following a coracoacromial ligament resection. Based on the present study, a limited acromioplasty with coracoacromial ligament preservation may best provide decompression of the rotator cuff while avoiding potential anterosuperior glenohumeral translation.