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Background: Avascular necrosis (AVN) of the humeral head is characterized by osteonecrosis secondary to disrupted blood flow to the glenohumeral joint. Following collapse of the humeral head, arthroplasty, namely, total shoulder arthroplasty (TSA) or humeral head arthroplasty (hemiarthroplasty), is recommended standard of care. The literature is limited to underpowered and small sample sizes in comparing arthroplasty modalities. Therefore, the aims of this study were (1) to compare the 10-year survivorship of TSA and hemiarthroplasty in the treatment of AVN of the humeral head and (2) to identify differences in their revision etiologies., Methods: Patients who underwent primary TSA and hemiarthroplasty for AVN were identified using the PearlDiver database. TSA patients were matched by age, gender, and Charlson Comorbidity Index (CCI) to the hemiarthroplasty cohort in a 4:1 ratio because TSA patients were generally older, sicker, and more often female. The 10-year cumulative incidence rate of all-cause revision was determined using Kaplan-Meier survival analysis. Multivariable analysis was conducted using Cox proportional hazard modeling. χ 2 analysis was conducted to compare the indications for revisions between matched cohorts including periprosthetic joint infection (PJI), dislocation, mechanical loosening, broken implants, periprosthetic fracture, and stiffness., Results: In total, 4825 patients undergoing TSA and 1969 patients undergoing hemiarthroplasty for AVN were included in this study. The unmatched 10-year cumulative incidence of revision for patients who underwent TSA and hemiarthroplasty was 7.0% and 7.7%, respectively. The matched 10-year cumulative incidence of revision for patients who underwent TSA and hemiarthroplasty was 6.7% and 8.0%, respectively. When comparing the unmatched cohorts, TSA patients were at significantly higher risk of 10-year all-cause revision (HR: 1.39; P = .017) when compared to hemiarthroplasty patients. After matching, there was no significant difference in risk of 10-year all-cause revision (HR: 1.29; P = .148) and no difference in the observed etiologies for revision (P > .05 for all)., Conclusion: After controlling for confounders, only 6.7% of TSA and 8.0% hemiarthroplasties for humeral head AVN were revised within 10 years of index surgery. The demonstrated high and comparable long-term survivorship for both modalities supports the utilization of either for the AVN induced humeral head collapse., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Reverse total shoulder arthroplasty (RTSA) has become an increasingly popular treatment strategy in the management of complex proximal humeral fractures (PHFs). However, no definitive consensus has been reached regarding the optimal surgical timing of RTSA following PHF, particularly considering nonoperative management is often a viable option. Therefore, the aim of this study was (1) to identify optimal timing intervals that maximize the likelihood of revision following RTSA and (2) to determine differences in revision etiologies using the identified timing intervals., Methods: A retrospective cohort analysis of patients undergoing PHF-indicated RTSA from 2010 to 2021 was conducted using a national administrative claims database. Stratum-specific likelihood ratio (SSLR) analysis was conducted to determine data-driven timing strata between PHF and RTSA that maximized the likelihood of revision surgery within 2 years of RTSA. To control for confounders, multivariable regression analysis was conducted to confirm the identified data-driven strata's association with 2-year revision rates as well as compare the likelihood of various indications for revision including mechanical loosening, dislocation, periprosthetic joint infection (PJI), and periprosthetic fracture (PPF)., Results: In total, 11,707 patients undergoing TSA following PHF were included in this study. SSLR analysis identified 2 timing categories: 0-6 weeks and 7-52 weeks from the time of PHF to TSA surgery. Relative to the 0-6-week cohort, the 7-52-week cohort was more likely to undergo revision surgery within 2 years (OR 1.93, P < .001). Moreover, the 7-52-week cohort had significantly higher odds of revision indicated for dislocation (OR 2.24, P < .001), mechanical loosening (OR 1.71, P < .001), PJI (OR 1.74, P < .001), and PPF (OR 1.96, P < .001)., Conclusions: Using SSLR, we were successful in identifying 2 data-driven timing strata between PHF and RTSA that maximized the likelihood of 2-year revision surgery. As it can be difficult to determine whether RTSA or nonoperative management is initially more appropriate, considering the results of this study, an early trial of 4-6 weeks of nonoperative management may be appropriate without altering the risks associated with RTSA., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Body mass index (BMI) is a modifiable risk factor for medical and infectious complications following total shoulder arthroplasty (TSA). Previous studies investigating BMI were limited to the conventional classification system, which may be outdated for modern day patients. Therefore, the purpose of this study was to identify BMI thresholds that are associated with varying risk of 90-day medical complications and 2-year prosthetic joint infection (PJI) following TSA., Methods: A national database was utilized to identify 10,901 patients who underwent primary elective TSA from 2013 to 2022. Patients were only included if they had a BMI value recorded within 1 month prior to TSA. Separate stratum-specific likelihood ratio analyses, an adaptive technique to identify data-driven thresholds, were performed to determine data-driven BMI strata associated with varying risk of 90-day medical complications and 2-year PJI. The incidence rates of these complications were recorded for each stratum. To control for confounders, each BMI strata was propensity-score matched based on age, sex, hypertension, heart failure, chronic obstructive pulmonary disease, and diabetes mellitus to the lowest identified BMI strata for both outcomes of interest. The risk ratio (RR) and 95% confidence interval (CI) were recorded for each matched analysis., Results: The average age and BMI of patients was 70.5 years (standard deviation ±9.8) and 30.7 (standard deviation ±6.2), respectively. Stratum-specific likelihood ratio analysis identified two BMI strata associated with differences in the rate of 2-year PJI: 19-39 and 40+. The same strata were identified for 90-day major complications. When compared to the matched BMI 19-39 cohort, the risk of 2-year PJI was higher in the BMI 40+ cohort (RR: 2.7; 95% CI 1.39-5.29; P = .020). After matching, there was no significant difference in the risk of 90-day major complications between identified strata (RR: 1.19, 95% CI: 0.86-1.64; P = .288)., Conclusion: A data-driven BMI threshold of 40 was associated with a significantly increased risk of 2-year PJI following TSA. This is the first TSA study to observe BMI on a continuum and observe at what point BMI is associated with increased risk of 2-year PJI following TSA. Our identified BMI strata can be incorporated into risk-stratifying models for predicting both PJI and 90-day major complications to minimize both., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)