CT scan shows RSA with autograft or allograft may be reliable for glenoid augmentation
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Key takeaways:
- RSA with either structural bone autograft or allograft for glenoid augmentation improved clinical outcomes.
- Results showed 90% of patients had complete bony incorporation on CT scans.
According to presented results, reverse shoulder arthroplasty with either structural bone autograft or allograft to augment the reconstruction of the glenoid yielded improved clinical outcomes and bony incorporation on CT scan.
Jay D. Keener, MD, presented results from his study on structural bone graft for RSA at the International Congress on Shoulder and Elbow Surgery.
“There is some controversy in terms of how well bone grafts heal after RSA,” Keener told Healio.
Keener and colleagues retrospectively enrolled 35 patients and prospectively enrolled 32 patients who underwent either primary or revision RSA with either structural bone autograft (n= 46) or allograft (n = 21) for glenoid augmentation. Outcomes included American Shoulder and Elbow Surgeons scores, VAS pain scores and bony incorporation of autografts and allografts on CT imaging at 1-year postoperatively.
Overall, mean ASES score improved from 33.1 preoperatively to 78.2 postoperatively. Postoperative radiographs revealed 63 patients (94%) had stable RSA constructs, while four patients (6%) had glenoid baseplate subsidence. Among the 50 patients who completed postoperative CT scans, 45 patients (90%) had complete graft incorporation; four patients (8%) had partial incorporation; and one patient (2%) had no graft incorporation. Keener noted no correlation between baseplate subsidence and graft choice for either primary or revision RSA.
“This prospective series shows good graft incorporation in over 90% of shoulders treated with RSA combined with bone grafting of the baseplate, despite having significant glenoid deformities. The incidence of baseplate loosening was 6%,” Keener said. “In this series, both autograft and allograft had similar healing rates. This research provides further evidence of the potential utility of glenoid bone graft in the setting of complex RSA,” he added.
Perspective
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Glenoid bone defects encountered during RSA are multifactorial, including posterior glenoid wear in osteoarthritis, superior glenoid wear in cuff tear arthropathy and various cavitary and complex bone defects. These defects can be challenging to address, especially in RSA, because the native humeral head is unavailable for use as a local autograft, and because it is often difficult to anticipate the precise glenoid bone defect prior to extricating the original components.
Keener and colleagues at Washington University in St. Louis used postoperative CT to demonstrate high rates of incorporation when using structural bone grafts to address glenoid bone defects at the time of both primary and revision RSA. Additionally, they found no difference in rates of graft incorporation between structural autograft and allograft.
Autograft humeral head remains a viable alternative to an augmented baseplate, although each option has its nuanced pros and cons. Structural allograft incorporates readily in most cases, obviating the need for iliac crest bone graft harvest and the associated added morbidity.
With an even larger sampling, the authors might have been able to stratify their results by primary or revision surgery, or by type of defect (contained, uncontained), but I suspect the sampling of 65 heterogeneous patients precluded this. Additionally, it would be helpful to know if the authors routinely employed biologic adjuncts, such as recombinant human bone morphogenetic protein-2, to aid the incorporation of structural allograft.
Overall, this study is impactful and helps validate my current decision-making and strategies for addressing larger glenoid bone defects.
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Keener JD, et al. FP.02.01. Presented at: International Congress on Shoulder and Elbow Surgery; Sept. 5-8, 2023; Rome.
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