Hypothyroidism increases risk of 90-day and 1-year complications after primary rotator cuff repair: a retrospective cohort study

Purpose: Rotator cuff repair (RCR) is a widely performed orthopedic procedure with generally favorable outcomes. However, the influence of systemic conditions such as hypothyroidism on surgical recovery and long-term complications remains poorly understood. Given the known effects of thyroid dysfunction on metabolism, tissue repair, and musculoskeletal health, this study aimed to evaluate the association between hypothyroidism and both short- and long-term postoperative outcomes following primary RCR using a large, nationally representative dataset. Methods: A retrospective cohort study was conducted using data from the TriNetX Research Network, comprising over 100 healthcare organizations. Patients undergoing primary RCR between April 2005 and April 2024 were included. Hypothyroid patients were identified by a documented diagnosis within one week before surgery and matched 1:1 to euthyroid controls using propensity score matching based on demographics, comorbidities, and other shoulder-specific covariates. Postoperative complications were assessed at 90 days and 1 year. Results: The final matched cohort included 7,647 patients in both cases and controls. At 90 days, hypothyroid patients had significantly higher rates of pulmonary embolism, deep vein thrombosis, acute kidney injury, urinary tract infections, fracture, shoulder stiffness, and postoperative pain. At 1 year, increased risks persisted for pulmonary embolism, deep vein thrombosis, acute kidney injury, urinary tract infections, fracture, shoulder stiffness, postoperative pain, sepsis, and shoulder replacement. Conclusion: Patients with hypothyroidism face significantly higher risks of complications following rotator cuff repair, including thromboembolic events, kidney injury, shoulder stiffness, and long-term issues like increased rates of shoulder replacement. These findings suggest that thyroid dysfunction may be associated with a greater overall burden of postoperative morbidity and may represent an underrecognized risk factor in patients undergoing rotator cuff repair.