Maimonides Evening of Research

Resident Winner

Samuel Swiggett

Comparison of Patient Demographics And Patient-Related Risk Factors For Dislocations Following Reverse Shoulder Arthroplasty


Samuel Swiggett, M.D.

Rushabh M. Vakharia, M.D., Joseph O. Ehiorobo, M.D., Martin W. Roche, M.D., Michael A. Mont, M.D., Ramin Sadeghpour, M.D., and Jack Choueka, M.D.


With the increasing number of reverse total shoulder arthroplasty (rTSA) procedures being performed worldwide, studies evaluating risk factors for dislocation following this procedure are limited. Therefore, the purpose of this study was to: 1) compare patient demographics; and 2) identify risk factors for dislocations following primary rTSA.


A retrospective query using a nationwide database was performed identifying patients who underwent primary rTSA. The inclusion criteria for the study group consisted of all patients who had a dislocation within 2 years following the index procedure. rTSA patients with a history of another primary arthroplasty was excluded from the analysis. Study group patients were compared to controls by examining patient demographics. The query yielded 45,578 patients with (n = 896) and without (n = 45,578) dislocations following primary rTSA. Patient demographics were compared using Pearson’s χ2 analyses. Multivariate binomial logistics regression analysis was performed to calculate odds-ratios (OR) and respective 95% confidence intervals (95% CI) on impact of patient-related risk factors for dislocations following primary rTSA. A p-value less than 0.01 was considered statistically significant.


Study group patients between the ages of 65 to 69 were found to have higher incidence of dislocations (21.8 vs. 20.6%, p<0.0001). Patients experiencing dislocations following primary rTSA were also more likely to be male patients (59.2 vs. 35.3%, p<0.0001). Study group patients also had higher comorbidity burden compared to control patients, as demonstrated by higher Elixhauser-Comorbidity Index scores (8 vs. 6, p<0.0001). The greatest patient-related risk factors for dislocations included being male (OR: 3.00, 95% CI: 2.59 – 3.48, p<0.0001), opioid use disorder (OR: 1.52, 95% CI: 1.12 – 2.02, p=0.005), hypertension (OR: 1.35, 95% CI: 1.04 – 1.80, p=0.02), BMI greater than 40 kg/m2 (OR: 1.31, 95% CI: 1.03 – 1.66, p=0.02), depression (OR: 1.29, 95% CI: 1.11 – 1.50, p=0.0005), and tobacco use (OR: 1.21, 95% CI: 1.03 – 1.43, p=0.01).

Conclusion Implication

As the number of primary rTSA procedures increase worldwide, identification of patient-related risk factors for dislocations is of great importance. The study is vital as it can allow orthopedic surgeons to properly identify and educate these patients of the potential complication following their procedure.