Rotator cuff injury is one of the most common causes of shoulder pain and functional impairment, and its incidence increases substantially with age. Arthroscopic rotator cuff repair has become the gold-standard treatment for rotator cuff tears; however, surgical success does not necessarily result in optimal functional recovery. A considerable proportion of patients continue to experience persistent pain, muscle weakness, and restricted range of motion after surgery, leading to unsatisfactory outcomes. Postoperative rehabilitation is a critical component of rotator cuff repair and requires an appropriate balance between the biological requirements of tendon healing and the rehabilitative goal of functional recovery. To protect the repaired tendon during early healing, conventional rehabilitation protocols typically involve strict immobilization during the early postoperative period, followed by cautious, progressive, low-load exercise. However, this strategy inevitably results in rapid disuse atrophy and loss of strength in the periarticular shoulder muscles. Blood flow restriction training (BFRT) , developed in Japan in 1966, combines low-load resistance exercise with tourniquet-mediated restriction of arterial inflow and venous outflow. By partially restricting blood flow to the limb, BFRT can induce substantial gains in muscle strength and hypertrophy at low exercise intensities. BFRT has been increasingly used in postoperative orthopaedic rehabilitation and can improve muscle strength, particularly when low-load BFRT produces effects comparable to those of high-load resistance training. Low-intensity BFRT induces acute hemodynamic responses in the affected limb, with systolic blood pressure decreasing significantly after exercise and then returning to baseline. It may therefore be a suitable option for patients unable to tolerate high-intensity rehabilitation. BFRT has also demonstrated beneficial effects on joint pain and limb stability, suggesting that it may provide an alternative approach to enhancing muscle strength and accelerating recovery after rotator cuff repair. Numerous studies of lower-extremity BFRT have confirmed its effectiveness in improving muscle strength, muscle size, and endurance. Nevertheless, its clinical value in rehabilitation after shoulder arthroscopy remains insufficiently investigated.

To investigate the effects of low-intensity BFRT on muscle strength, shoulder function, and time to return to activity after arthroscopic repair of small- to medium-sized rotator cuff tears.

Patients who underwent arthroscopic rotator cuff repair at our institution between January 2022 and December 2024 were assigned to a BFRT group (n = 37) or a control group (n = 35) . Both groups received a standardized postoperative rehabilitation program. Beginning in the second postoperative week, the BFRT group underwent low-intensity resistance training at 20% of the one-repetition maximum, combined with individualized blood flow restriction at 50% of the limb occlusion pressure. Peak torque during shoulder external rotation and forward flexion was measured using an isokinetic strength-testing system preoperatively and at 8 and 24 weeks postoperatively. Shoulder function was evaluated using the American shoulder and elbow surgeons (ASES) score. The time required to return to activities of daily living and light physical activity was also recorded.

At 8 weeks postoperatively, the BFRT group demonstrated significantly greater peak torque during external rotation than the control group [ (10.48±0.75) N . m, (8.93±0.88) N . m, P < 0.001] and significantly greater peak torque during forward flexion [ (16.58±0.87) N . m, (14.08±1.06) N . m, P < 0.001] . The ASES score at 8 weeks was also significantly higher in the BFRT group than in the control group [ (74.38±2.99) points, (67.80±3.48) points, P < 0.001] . At 6 months postoperatively, the BFRT group continued to demonstrate significantly greater external-rotation peak torque [ (14.30±0.82) N . m, (11.82±1.04) N . m, P < 0.001] and forward-flexion peak torque [ (22.51±1.06) N . m, (19.21±1.34) N . m, P < 0.001] . The 6-month ASES score was significantly higher in the BFRT group [ (88.08±2.43) points, (81.23±3.15) points, P < 0.001] . Patients in the BFRT group returned to activities of daily living significantly earlier than those in the control group [ (3.60±0.38) weeks, (4.95±0.50) weeks, P < 0.001] . They returned to light physical activity earlier as well [ (7.93±0.47) weeks, (9.81±0.66) weeks, P < 0.001] .

BFRT improves peak torque of the periarticular shoulder muscles and patient-reported shoulder function after arthroscopic rotator cuff repair while shortening the time required to return to activity. The beneficial effects of BFRT on muscle performance may underlie these improvements.