Safety of arthroscopic rotator cuff repair: using a core event set for clinician and patient assessment of risks in a multicenter cohort study.

Objectives: Reporting standards for adverse events (AEs) in arthroscopic rotator cuff repair (ARCR) vary. A standardized "core event set" (CES) was developed to enhance AE documentation. This study describes AE risks in a large Swiss-German ARCR cohort, evaluates concordance between patient-reported and clinician-reported events, and investigates AE variability according to tear severity. Design: Prospective multicenter cohort study. Setting: Between June 2020 and November 2021, 973 patients were enrolled across 19 orthopedic centers and followed for 24 months. Participants: Adult patients with a rotator cuff tear. Interventions: Primary ARCR. Main outcome measures: AEs were documented using a structured CES and classified into five severity grades. AE reporting was compared between patients and clinical staff. AE cumulative risks (CR) were calculated by occurrence period, severity grade, and tear severity. Results: A total of 342 AEs were documented in 314 patients within 2 years. Of these, 41% were reported only by clinical staff, 40% only by patients, and 19% by both. The 2-year CR of AEs was 29.1%, with persistent pain (12.2%) and deep soft tissue complications (10.6%) being most common. Severity classification revealed 61.7% grade I, 24.3% grade II, 13.2% grade III, and 0.9% grade IV. Tear severity was inversely associated with overall AE risk, ranging from 41.5% in partial tears to 28% in massive tears. Conclusions: Standardized AE documentation using CES identified pain, deep soft tissue complications, and rotator cuff issues as the most frequent local AEs. Both clinicians and patients should be involved in AE reporting. Most AEs were mild, and tear severity predicted AE risk, highlighting the need for tailored postoperative strategies and further research on preventive measures.