Characteristics and Risk Factors for 90-Day Readmission Following Shoulder Arthroplasty.

ABSTRACT Background Anatomic and reverse total shoulder arthroplasty (aTSA, rTSA) are the standard of care for end-stage shoulder arthritis. Advancements in implant design, perioperative management, and patient selection have allowed shorter inpatient admissions. Unplanned readmissions remain a significant complication. Identification of risk factors for readmission is prudent as physicians and payers prepare for the adoption of bundled care reimbursement models. The purpose of the present study is to identify characteristics and risk factors associated with readmission following shoulder arthroplasty using a large, bi-institutional cohort. Methods 2,805 Anatomic and 2,605 reverse total shoulder arthroplasties drawn from two geographically diverse, tertiary health systems were examined for unplanned inpatient readmissions within 90 days following the index surgery (primary outcome). 40 preoperative patient sociodemographic and comorbidity factors were tested for their significance using both univariable and multivariable logistic regression, and backwards stepwise elimination selected for the most important associations for 90-day readmission. Readmissions were characterized as “medical” or “surgical” and subgroup analysis was performed. Short length of stay (discharge by postoperative day 1) and discharge to facility were also examined as secondary outcomes. Parameters associated with increased readmission risk were included in a predictive model. Results Within 90 days of surgery, 175 patients (3.2%) experienced an unanticipated readmission, with no significant difference between institutions (p=0.447). There were more readmissions for surgical complications than medical complications (62.9% vs. 37.1%, p Conclusion Risk factors for unplanned 90-day readmission following shoulder arthroplasty include reverse shoulder arthroplasty, surgery for revision and fracture, and right sided surgery. Additionally, there are several modifiable and non-modifiable risk factors which can be used to ascertain a patient’s readmission probability. Shorter inpatient stays are not associated with increased risk of readmission, whereas discharge to post-acute care facilities does impose a greater risk of readmission. As scrutiny around health care cost increases, identifying and addressing risk factors for readmission following shoulder arthroplasty will become increasingly important. Level of Evidence Level III; Retrospective Case-Control Design; Prognosis Study