Arthroscopic Versus Open Iliac Crest Bone Grafting in Recurrent Anterior Shoulder Instability With Glenoid Bone Loss: A Computed Tomography-Based Quantitative Assessment

Purpose: To assess the iliac crest bone graft (ICBG) position in the en-face view and axial plane comparing arthroscopic with open procedures. Methods: A total of 40 consecutive patients with recurrent anterior shoulder instability and glenoid bone loss over 10% treated by 2 independent orthopaedic departments were included. Two independent observers analyzed preoperative and immediate postoperative computed tomography scans of 20 open (group O) and 20 arthroscopic (group A) procedures. Defect and ICBG characteristics of the J-shaped graft in the en-face view and axial plane were manually assessed by multiplanar reconstructed computed tomography scans. Variances in terms of graft positioning were analyzed. Results: No significant variances in arthroscopic graft positioning were observed. The graft position in the en-face view was comparable in both groups, with the superior extent of the arthroscopic graft (40 degrees +/- 9 degrees [inferior extent, 139 degrees +/- 16 degrees]) lying significantly higher than the superior extent in group O (50 degrees +/- 13 degrees, P = .005 [inferior extent, 147 degrees +/- 21 degrees; P = .178]). The covered glenoid defect size was above 95% (98% +/- 1% in group O vs 95% +/- 2% in group A, P = .001). The arthroscopic graft in the axial plane showed a significantly steeper impaction angle (34.8 degrees +/- 7.8 degrees vs 26.9 degrees +/- 9.9 degrees, P = .010), with a significantly increased medial offset compared with group O (6.6 +/- 1.7 mm vs 5.4 +/- 1.3 mm, P = .024). The mediolateral step formation, however, was not significantly different (2.9 +/- 1.1 mm in group A vs 3.2 +/- 0.8 mm in group O, P = .289). The interobserver reliability was very good for all measurements (R = 0.969; 95% confidence interval, 0.965-0.972). Conclusions: Positioning of the arthroscopic ICBG in the en-face view and axial plane is comparable to that of the open technique. Good glenoid defect coverage and glenoid concavity reconstruction can be achieved with the arthroscopic technique. The main difference compared with the open procedure is the significantly steeper impaction angle.