Three Year Outcomes After Shoulder Arthroplasty

Contemporary shoulder arthroplasty systems incorporate modular components, updated implant geometry, three-dimensional (3D)-printed technology, and preoperative 3D surgical planning to support patient-specific implant selection and intraoperative decision-making. Although these features are intended to improve procedural efficiency and flexibility, multicenter evidence regarding their clinical performance and associated patient outcomes remains limited. This multicenter observational cohort study will evaluate patients who underwent primary anatomic total shoulder arthroplasty (aTSA) or reverse total shoulder arthroplasty (rTSA) using a single contemporary shoulder arthroplasty platform between 2020 and 2024. The study will combine retrospective review of existing clinical data with prospective collection of missing two- or three-year patient-reported outcome measures at a single follow-up time point. No investigational treatment, study-directed procedure, or alteration to routine clinical care will occur. Existing electronic medical records, operative reports, imaging, preoperative planning files, implant information, and patient-reported outcome databases will be retrospectively reviewed. Data collected will include demographic and clinical characteristics, surgical and implant details, preoperative planning parameters, postoperative function, patient-reported outcomes, complications, readmissions, reoperations, and revisions. When two- or three-year patient-reported outcomes are not available through routine clinical follow-up, participants may be contacted to complete a one-time validated questionnaire by telephone or secure electronic survey. The primary analysis will evaluate whether three-year outcomes after aTSA are non-inferior to those after rTSA using the American Shoulder and Elbow Surgeons score and a prespecified non-inferiority margin of 9 points. Additional analyses will compare functional outcomes, complications, and revision rates between the two procedure groups. Among patients with available preoperative 3D planning data, the study will also evaluate agreement between the planned and implanted glenoid and humeral components. Investigators will characterize the frequency and types of intraoperative deviations from the surgical plan and assess whether these deviations are associated with postoperative outcomes, complications, patient satisfaction, or revision surgery. The target sample size is up to 300 participants, with approximately 150 participants in each procedure group.