Objective:To investigate the outcome of using long head of biceps tendon (LHBT) transposition to augment arthroscopic massive rotator cuff repair.Methods:A retrospective case series study was performed on 22 patients with massive rotator cuff tear treated in Zhongshan Hospital, Xiamen University from June 2019 through July 2020, including 12 males and 10 females, aged 54-79 years [(63.9±6.8)years]. LHBT transposition was performed to augment arthroscopic repair of massive rotator cuff tear. The active range of motion (forward flexion, abduction, external rotation), visual analog scale (VAS), University of California Los Angeles (UCLA) score and American Shoulder and Elbow Surgeons (ASES) score were compared preoperatively and at 3 months and 12 months postoperatively. The cuff integrity was evaluated using MRI following Sugaya classification at 12 months postoperatively. LHBT dislocation or distal retraction was recorded at the last follow-up.Results:All patients were followed up for 12-24 months [(17.0±3.8)months]. The postoperative 3-month active forward flexion [162.5(160.0, 170.0)°] and abduction [170.0(160.0, 170.0)°] were improved compared with preoperative measurements [90.0(73.8, 120.0)°,85.0(70.0, 112.5)°](all P<0.05). However, no statistically significant difference was found between the preoperative and postoperative 3-month external rotation [50.0(37.5,60.0)° vs. 60.0(48.8,70.0)°] ( P>0.05). The postoperative 12-month active forward flexion, abduction and external rotation were 170.0(160.0, 175.0)°, 170.0(170.0, 177.8)° and 60.0(48.8, 70.0)°, showing no significant improvement from those at 3 months postoperatively (all P>0.05). The postoperative 3-month VAS [1.0(0.8, 2.0)points], UCLA score [23.0(23.0, 25.0)points] and ASES score [79.1(72.9, 83.3)points] were improved significantly compared with preoperative measurements [7.0(8.0, 9.0)points, 9.0(10.0, 14.0)points, 25.0(16.6, 31.6)points] (all P<0.05). The postoperative 12-month UCLA score [33.0(31.0, 35.0)points] and ASES score [91.6(86.6, 93.3)points] were further improved compared with those at 3 months postoperatively (all P<0.05). However, the postoperative 12-month VAS [0.0 (0.0, 1.0)points] showed no statistically significant difference with that at 3 months postoperatively ( P>0.05). The UCLA score was excellent in 6 patients and good in 16 at 12 months postoperatively.MRI revealed healed tendons with continuity in 16 patients, with the healing rate of 72.7%, and partially retears with good shoulder function in 6 patients, with the retearing rate of 17.3%. No LHBT dislocation or distal retraction was found at 12 months postoperatively in regardless of mild anterior shoulder pain in 2 patients. Conclusion:Using LHBT transposition to augment arthroscopic massive rotator cuff repair has yielded excellent shoulder range of motion, shoulder function recovery, pain relief and high tendon healing rate with rare postoperative complication.