Abstract:[Objective] To investigate the clinical outcomes of arthroscopic repair with remnant preservation and perpendicular micro- fracture as bone marrow stimulation for acute rotator cuff tear. [Methods] A retrospective study was done on 64 patients who received ar- throscopic double-row repair for acute rotator cuff tear in our hospital from May 2018 to May 2020. According to doctor-patient communi- cation, 32 patients had the rotator cuff repaired in condition of remnant preservation and perpendicular microfracture as bone marrow stimu- lation (the modified group), while the other 32 patients were repaired by traditional bone bed fresh technique (the traditional group). The perioperative, follow-up and imaging results were compared between the two groups. [Results] All patients in both groups had correspond- ing surgical procedures performed successfully, and there were no statistically significant differences in operation time, intraoperative blood loss, incision healing, active activity time and hospital stay between the two groups (P>0.05). All of them were followed up for (31.9±3.4) months in a mean, and there was no significant difference in time to resume full weight-bearing activity between the two groups (P>0.05). The VAS, Constant-Murley, UCLA and ASES scores, as well as shoulder forward flexion, upward lifting, abduction upward lifting range of motions (ROMs) in both groups were significantly improved at the last follow-up compared with those preoperatively (P<0.05), which proved not statistically significant between the two groups at any time points accordingly (P>0.05). With regard of imaging, tendon integrity was significantly improved in both groups at the last follow-up compared with that pre-surgery (P<0.05), while the acromiohumeral dis- tance (AHD), the extents of tendon fat infiltration and the tendon atrophy remained unchanged in both groups (P>0.05). By the latest followup, the modified group was significantly superior to the traditional group in terms of tendon integrity [I/II/III/IV/V, (20/11/0/0/1) vs (15/9/0/ 5/3), P=0.042] and retear rate (3.1% vs 25.0%, P=0.026). [Conclusion] Arthroscopic repair of acute rotator cuff tears with remnant preser-vation and bone marrow stimulation by perpendicular microfracture does relieve pain, enhance shoulder function score, improve shoulder motion, and achieve good clinical consequences, which may provide a new choice for clinicians in the treatment of acute rotator cuff tears.