Comparison of the Coracoid, Distal Clavicle, and Scapular Spine for Autograft Augmentation of Glenoid Bone Loss: A Radiologic and Cadaveric Assessment

Abstract

Background: Glenohumeral instability caused by bone loss requires adequate bony restoration for successful surgical stabilization. Coracoid transfer has been the gold standard bone graft; however, it has high complication rates. Alternative autologous free bone grafts, which include the distal clavicle and scapular spine, have been suggested. Study Design: Controlled laboratory study. Purpose: The purpose of this study was to determine the percentage of glenoid bone loss (GBL) restored via coracoid, distal clavicle, and scapular spine bone grafts using a patient cohort and a cadaveric evaluation. Methods: Autologous bone graft dimensions from a traditional Latarjet, congruent arc Latarjet, distal clavicle, and scapular spine were measured in a 2-part study using 52 computed tomography (CT) scans and 10 unmatched cadaveric specimens. The amount of GBL restored using each graft was calculated by comparing the graft thickness with the glenoid diameter. Results: Using CT measurements, we found the mean percentage of glenoid restoration for each graft was 49.5% ± 6.7% (traditional Latarjet), 45.1% ± 4.9% (congruent arc Latarjet), 42.2% ± 7.7% (distal clavicle), and 26.2% ± 8.1% (scapular spine). Using cadaveric measurements, we found the mean percentage of glenoid restoration for each graft was 40.2% ± 5.0% (traditional Latarjet), 53.4% ± 4.7% (congruent arc Latarjet), 45.6% ± 8.4% (distal clavicle), and 28.2% ± 7.7% (scapular spine). With 10% GBL, 100% of the coracoid and distal clavicle grafts, as well as 88% of scapular spine grafts, could restore the defect ( P < .001). With 20% GBL, 100% of the coracoid and distal clavicle grafts but only 66% of scapular spine grafts could restore the defect ( P < .001). With 30% GBL, 100% of coracoid grafts, 98% of distal clavicle grafts, and 28% of scapular spine grafts could restore the defect ( P < .001). With 40% GBL, a significant difference was identified ( P = .001), as most coracoid grafts still provided adequate restoration (congruent arc Latarjet, 82.7%; traditional Latarjet, 76.9%), but distal clavicle grafts were markedly reduced, with only 51.9% of grafts maintaining sufficient dimensions. Conclusions: The coracoid and distal clavicle grafts reliably restored up to 30% GBL in nearly all patients. The coracoid was the only graft that could reliably restore up to 40% GBL. Clinical Relevance: With “subcritical” GBL (>13.5%), all autologous bone grafts can be used to adequately restore the bony defect. However, with “critical” GBL (≥20%), only the coracoid and distal clavicle can reliably restore the bony defect.

Morphometric and Biomechanical Comparison of the Scapular Spine and Coracoid Graft in Anterior Shoulder Instability

“…29 Therefore, the ability for glenoid restoration of the scapular spine is worth investigating. Rodriguez et al 36 found that the scapular spine was capable of achieving 28.2% glenoid restoration on average, compared with 31% in our results. The difference might be attributed to the different graft lengths harvested in the study.…”

Open Glenoid Augmentation With Scapular Spine Autograft for Recurrent Shoulder Instability: A Report of Two Cases

“…There are limitations to the thickness of the graft that can be acquired given the depth of the scapular spine, therefore the amount of glenoid bone loss should be considered. With that said, studies have suggested that up to an average of 26% of glenoid bone loss can be adequately treated with scapular spine autograft [ 3 ]. Scapular spine autograft for glenoid bone loss should be considered as an option alongside other treatments for glenoid bone loss after adequate assessment of percent bone loss.…”

“…Optimal treatment for these patients with significant bone loss remains a topic of discussion with a wide array of autograft and allograft techniques utilized for glenoid augmentation. The Latarjet procedure, using coracoid autografts, is perhaps most commonly used to restore glenoid bone loss; however, high complication rates of coracoid grafts have urged the exploration of other graft options [3]. Several studies have identified scapular spine autograft to be suitable for restoring glenohumeral stability from bone quality and biomechanical standpoints; however, there are few reports on the indications and details of this procedure [4][5][6].…”

Free Bone Block Procedures for Glenoid Reconstruction in Anterior Shoulder Instability

“…Recent work has shown that the DCA can reliably restore up to 30% glenoid bone loss. 41 However, a different study showed that DCA was able to reconstruct 22% of the glenoid face. 42…”

“…First, the scapular spine graft only seems to be suitable for reconstruction of relatively small glenoid bone defects because a study showed that only 66% of scapular spine grafts were able to restore a 20% glenoid bone loss defect. 41 Furthermore, the scapular spine significantly narrows from the posterior crest toward the supraspinatus fossa, drawing concern for potential bony fracture during screw placement (Figure 5). 41 Second, this graft does not contain cartilage because it is nonarticular.…”