Pre-operative glenoid bone density varies by indication for reverse shoulder arthroplasty: a comparison of glenoid bone density in proximal humerus fractures, glenohumeral osteoarthritis, and rotator cuff arthropathy.

BACKGROUND

Glenoid bone mineral density (BMD) has important implications for the fixation of glenoid components and may vary based on indications for reverse total shoulder arthroplasty (rTSA).17 Careful consideration of pre-operative bone quality can enable surgeons to improve pre-operative and intraoperative decision-making for glenoid component fixation and reduce associated complications, such as aseptic loosening. There remains a paucity of literature exploring such implications in rTSA. We hypothesize that BMD varies by indication diagnosis for rTSA.

METHODS

A retrospective chart review was conducted on patients receiving an rTSA from a single surgeon from March 2021-May 2024 with one of the 3 following diagnoses: proximal humerus fracture (FX), glenohumeral osteoarthritis (GHOA), and rotator cuff arthropathy (RCA). Pre-operative computerized tomography scans were analyzed for glenoid BMD. Differences in BMDs across different shoulder pathologies were assessed with general linear regression models adjusted for age and body mass index.

RESULTS

In sum, 150 patients were identified who underwent an rTSA for one of the 3 following diagnoses: FX (n = 24, 16%), GHOA (n = 64, 43%), and RCA (n = 62, 41%). Fifty-one (34%) of patients were male and 99 (66%) of patients were female. Average subchondral BMD was 150 Hounsfield Units (HUs) (95% confidence interval of 92-207 HUs) for FX, 304 HUs (268-339 HUs) for GHOA, and 208 HUs (172-244 HUs) for RCA. Subchondral bone in patients with GHOA was significantly denser than FX and RCA (P < .01). Average anterior cortex bone density was 1,206 HUs (113-1,299 HUs), 1,262 HUs (1,205-1,319 HUs), and 1,198 HUs (1,140-1,256 HUs) for FX, GHOA, and RCA patients, respectively. No statistically significant differences in anterior cortical HU were observed across the 3 pathologies in this study. Average posterior cortex bone density was 876 HUs (763-990 HUs), 969 HUs (889-1,038 HUs), and 959 (888-1,030 HUs) for FX, GHOA, and RCA patients, respectively. No statistically significant differences in posterior cortical HUs were observed across the 3 pathologies in this study.

CONCLUSION

This study demonstrates that subchondral glenoid BMD varies among patients undergoing rTSA depending on the underlying pathology. Fracture rTSAs have the lowest subchondral BMD when compared to GHOA and RCA patients. BMD of the anterior cortex appears equivalent despite indication for rTSA. Incorporating glenoid BMD assessments into surgical planning may enhance implant fixation and possibly avoid complications such as implant loosening. Further prospective studies are warranted to validate and refine clinical decision-making based on glenoid bone quality.