Arthroscopic Capsular Release for the Stiff Shoulder

Abstract

The anatomic proximity of several neurovascular structures remains a major concern to the surgeon interested in performing arthroscopic capsular re lease. We evaluated the anatomic relationships be tween the released capsule and the axillary nerve, posterior circumflex humeral artery, and brachial ar tery in a frozen cadaveric model. With the aid of electrocautery, seven cadaveric shoulders under went complete arthroscopic capsular release. The release was performed circumferentially, approxi mately 1 cm lateral to the glenoid rim. All shoulders were subsequently frozen and sectioned through the plane of the capsular release while the shoulder was maintained in the lateral arthroscopic position (45° of abduction and 20° of flexion). Anatomic dissection revealed an average distance from the capsular re lease to the axillary nerve of 7.04 mm (95% confi dence interval, 5.62, 8.47), to the posterior circum flex humeral artery of 8.2 mm (95% confidence interval, 6.41, 9.99), and to the brachial artery of 15.97 mm (95% confidence interval, 9.85, 22.09). As the axillary nerve was followed medially from the released capsule, the inferior border of the subscap ularis muscle became interposed between the cap sule and the axillary nerve. This limited anatomic study shows that a relatively safe margin between the capsule and the neighboring neurovascular structures can be obtained by releasing the capsule within 1 cm of the glenoid rim.