CT-based quantitative assessment of the surface size and en-face position of the coracoid block post-Latarjet procedure

Background: The success of shoulder stabilization with the Latarjet procedure might depend on the size of the bone graft and the positioning of the coracoid at the glenoid. The aim of this study was to quantitatively assess the surface of the coracoid bone graft and to assess its positioning in the en-face view. Method: A series of 21 patients (17 men, 4 women, 26.1 ± 6.8 years - 9 right, 12 left shoulders) were prospectively included and followed up with CT scans between December 2010 and April 2012 at an average of 2.4 ± 0.7 months postoperatively. The retrospective analysis of the CT scans was performed with Osirix™ software. The coracoid surface was measured (cm²) in the sagittal plane. The positioning in relation to the center of the circumscribed circle of the glenoid was determined in the en-face clock face view of the glenoid. Results: The grafts had a mean surface of 1.61 ± 0.51 cm² (mean ± standard deviation). The coracoid grafts were located between 01:05 hours (32.5) and 05:33 hours (166.6). Mean positioning was 02:00 hours (59.8 ± 16.1) to 04:26 hours (133.0 ± 16.9). The extent of the grafts was 73.2 ± 14.3. Discussion: The positioning of the coracoid graft on the clock face of the glenoid is situated in the decisive zone of 02:30-04:20 hours. The mean surface of the graft is smaller than expected from anatomical studies, but restores in defect situations bone stock in the potential defect areas at the anterior glenoid rim. Level of evidence: Level IV, prospective case series, treatment study.