Demographic and radiographic predictors of patient reported outcomes and revision surgery after stemless total shoulder arthroplasty

Background: Stemless total shoulder arthroplasty (TSA) is aimed at better re-creating native anatomy, facilitating revision, and preserving bone. The purpose of this study is to determine which pre-operative patient characteristics or radiographic parameters were predictive of outcomes following stemless TSA. Methods: This was a retrospective review of prospectively collected data. One hundred fifty-seven patients with glenohumeral osteoarthritis were prospectively enrolled as part of a multi-center FDA Investigational Device Exemption protocol in July 2011-November 2012. In the present study, one hundred forty-nine patients with minimum 2-year follow-up had imaging available for review and were included (107 men, 42 women). Mean age 65 years (range,37-84). Pre-operative patient demographics, baseline ASES and Constant scores, deltoid tuberosity index (DTI), combined cortical thickness, and postoperative glenoid version were analyzed to predict treatment success. Treatment success was defined by no revision procedures and an adjusted Constant score of >85% at final follow-up. Statistical analyses were performed using student T-test, multiple logistic regression, and Pearson correlation with a p-value of 0.05 defining significance. Intraclass correlation and kappa values were calculated to determine interrater reliability for radiographic measurements. Results: Three patients (2.0%) underwent revision or explant due to infection, unstable implant, or glenoid loosening. Eleven (7.4%) had an adjusted Constant score <85% at 2-year follow-up. These patients made up the suboptimal treatment outcome cohort (n = 13), with a mean age of 55.5 compared to 66.6(P <0.001). Relative risk for suboptimal outcome for patients <60 years was 1.32(95% CI:1.05-1.66). Baseline Constant was lower in the suboptimal treatment group (47.9 vs. 57.0, p=0.001). There were no differences between groups when comparing radiographic parameters. Older age correlated with lower combined cortical thickness (r = 0.32, P <0.05), lower DTI(r = 0.17, P <0.05), greater Constant(r = 0.47, P <0.05) and ASES(r = 0.29, P <0.05) scores at follow-up. Conclusion: Patients younger than 60 years old had a 1.3x risk of suboptimal treatment outcome following stemless TSA, similar to what is seen with stemmed implants. Low radiographic bone density was not predictive of suboptimal constant score or reoperation at final follow-up. Older patients had decreased combined cortical thickness and deltoid tuberosity index, yet were more likely to have a successful outcome following stemless TSA compared to younger patients. Level of evidence: Level III; Retrospective Cohort

Duke Scholars

Author Tally Edward Lassiter Orthopaedic Surgery

Author Brian Chei-Fai Lau Orthopaedic Surgery