The relationship of the axillary nerve to arthroscopically placed capsulolabral sutures. An anatomic study.

Ten cadaveric shoulders (mean donor age, 60.5 years) underwent arthroscopic placement of capsulolabral sutures as performed during arthroscopic reconstruction for shoulder instability. In relation to the glenoid face, the sutures were placed anterior, anteroinferior, inferior, posteroinferior, and posterior. All sutures entered the capsule approximately 1 cm away from the glenoid and exited beneath the labrum, and were tied using arthroscopic knot-typing techniques. The shoulders were frozen in the lateral arthroscopic position of approximately 45 degrees of abduction and 20 degrees of flexion and sectioned in the plane of the glenohumeral joint. The axillary nerve was then dissected, and the average distance from the nerve to each suture was found to be 16.7 mm at the anterior position, 12.5 mm at the anteroinferior position, 14.4 mm at the inferior position, 24.1 mm at the posteroinferior position, and 32.3 mm at the posterior position. In no specimen was any suture closer to the axillary nerve than 7 mm. We noted a statistically significant trend for the nerve to lie closest to the anteroinferior suture and gradually recede from the remaining sutures lying more posteriorly. This anatomic study is the first to demonstrate a relatively safe margin for arthroscopic suture placement between the capsule and axillary nerve when these sutures are placed approximately 1 cm from the glenoid rim.