This multicentre, prospective, before-and-after quality improvement study will evaluate a hospital-level closed-loop management programme for unplanned return to the operating room in orthopaedics. The unit of enrollment, intervention, and analysis is the participating hospital and its orthopaedic department. Approximately 20-30 secondary or tertiary public hospitals in China will be included. Individual patients will not be recruited as research participants, and only aggregated and de-identified hospital-level data will be collected.After baseline assessment and standardized training, participating orthopaedic departments will implement a closed-loop management programme comprising six core components: standardization of the definition of unplanned return to the operating room; establishment of a non-punitive reporting mechanism; appointment of a departmental coordinator; monthly case registration and multi-source data verification; regular department-wide case review and root-cause analysis; and development, implementation, and follow-up of continuous quality improvement actions.The primary outcomes include the underreporting rate or reporting accuracy and indicators of management quality, such as coordinator appointment, active reporting, case registration, data verification, case review, and completion of the closed-loop management process. Secondary outcomes include the rate of unplanned return to the operating room, common postoperative complications, mortality, unplanned readmission, length of hospital stay, and hospitalization costs. Intervention adherence will be assessed quarterly, and study outcomes will be evaluated every six months during the 36-month study period. The intervention will not alter patients' clinical treatment or require additional diagnostic or therapeutic procedures.