Anatomic considerations for arthroscopic glenoid reconstruction using iliac crest grafts: a radiologic study.

Abstract

Arthroscopic glenoid reconstruction using autografts is an advanced procedure that requires experience and preparation. Knowledge about anatomic pitfalls is therefore important to establish well-positioned portals and prevent neurovascular damage. We included 43 computed tomography scans from 43 patients. The distance between the tip of the coracoid process and a perpendicular line representing the anteroinferior glenoid was measured. From these results an anteroinferior working portal was designed, and the angulation needed for screw insertion to fixate a hypothetical graft was measured. In a second step, 9 patients underwent magnetic resonance imaging scans 34 ± 10 months after glenoid reconstruction, and the distance between the screw approach path and the neurovascular bundle was measured. In the analyzed scans, average defect size was 23%, and the coracoid process to the anteroinferior glenoid distance was 32 ± 7 mm. We thus hypothesized that a corridor 20 to 30 mm inferior to the coracoid process would be the ideal position for a working portal. Through this portal, 85% of screws could be applied with 0° to 30° angulation. When the postoperative scans were analyzed, the distance from the neurovascular bundle showed an average of 26 ± 6 mm for the superior screw and 21 ± 5 mm for the inferior screw. The ideal distance between the coracoid process and an anteroinferior working portal is 32 mm. Having established the portal, instruments should not be inserted pointing in a medial direction of the coracoid process due to the proximity of the neurovascular bundle.