Arthroscopic bone block augmentation of the anterior glenoid through the rotator interval: a cadaveric feasibility study

Abstract

Arthroscopic augmentation of the anterior glenoid using a free bone graft through the rotator interval is possible without compromising the fixation and position of the graft In 7 cadavers arthroscopic augmentation of the anterior glenoid was performed. A preshaped, free graft was introduced and fixated with 1 central screw without desinsertion or split of the subscapularis tendon. Postoperatively, the orientation and position of the screw and position of the graft in the vertical and horizontal plane were analyzed on computer tomography (CT) scan. Macroscopic dissection was performed to assess damage to the conjoined and subscapularis tendon and surrounding neurovascular structures and to verify the position of the graft. Postoperative CT scans showed no intra-articular perforation of the screw. The mean inclination angle in the axial plane was 21,2° (range, 9-48°). Postoperative dissection showed no damage to surrounding neurovascular structures. Fraying occurred at the lateral border of the conjoined tendon in 3 specimens, at the upper border of the subscapularis in 5 cases, but no tears were noted. In the vertical plane, the augmentation block was correctly (subequatorial) positioned in 5 cases; 2 blocks were at the level of the equator. In the horizontal plane, the augmentation block was flush with the articular surface in 5 cases and too medial in 2 cases (<5 mm). This study showed that it is technically possible to perform a bone block procedure arthroscopically through the rotator interval without compromising the position and fixation of the graft and fixation screw.