Advances in arthroscopic rotator cuff repairs techniques such as single-row, double-row, transosseous-equivalent technique (also called "suture bridge" ) , margin convergence and combined patch augmentation have been extensively adopted in clinic. However, despite the advances in repairing techniques, rather high re-tear incidence especially for large to massive tears have been reported from 20% to 94% after rotator cuff repairs. Considering that rotator cuff re-tear remain a substantial implication of functional outcomes after surgical repairing, biologically based strategies to improve the quality of tendon tissue after surgical reconstruction have gained increasing interest over the last several years. Stem cells, growth factors and other tissue engineering methods are increasingly being used to improve rotator cuff healing after repair. Mesenchymal stem cells (MSCs) have been suggested to promote rotator cuff healing and should be promoted clinically. Bone marrow stimulation technologies such as micro-fracture technology and multi-channel technology have also attracted much attention. This technology is simple, direct and inexpensive, which can provide sufficient MSCs for local tendon healing and promote the occurrence of microvascularization. This technique involves perforating the musculoskeletal joint, such as the foot print area of rotator cuff, into the cartilage and locally releasing BM-MSCs to facilitate healing. In a preclinical biomechanical study, the terminal failure load of rotator cuff was significantly increased in the BMS group compared with that in the control group. Animal studies have also shown that stem cells can infiltrate into the footprint area and ultimately strengthen the rotator cuff after repair. Hernigou et al. performed a case control study comparing patients who received simple single-row repair and enhanced repair with stem cells. The stem cell group had 100% intact repair at 6 months compared to 67% of control group, and at 10 years, the rate was 87% versus 44%. Several clinical studies and meta-analyses have found that bone marrow stimulation can definitely reduce the rate of re-tear after rotator cuff repair compared with conventional repair.

To evaluate the role of bone marrow stimulation technique in the improvement of rotator cuff healing and function.

The Cochrane Library, PubMed, Medline, Embase, CNKI, VIP, Wanfang and CBM and other databases were retrieved on the comparative studies of using bone marrow stimulation technology and simple rotator cuff repair, including clinical randomized controlled and retrospective cohort studies. manual search of The references of included studies were manually retrieved. The index data from each study was extracted, including overall re-tear rate, re-tear rate of large rotator cuff tears, postoperative shoulder joint mobility, visual analog scale (VAS) score, Constant-Murley score (CMS) , University of California, Los Angeles shoulder rating scale (UCLA) , American shoulder and elbow surgeons score (ASES) , and disabilities of the arm, shoulder, and hand questionnaire (DASH) . The Revman 5.3 software was used for analysis and process.

A total of 2 randomized controlled studies and 6 retrospective cohort studies were included in the Meta-analysis. Two uncontrolled retrospective studies and 2 uncontrolled retrospective studies and previous 8 studies were included in the systematic review. The meta-analysis only included the first 8 articles with 641 patients. The results of meta-analysis show that, compared with simple rotator cuff repair, rotator cuff repair combined with bone marrow stimulation technology can significantly improve the overall healing effect of rotator cuff [OR = 0.42, 95% CI (0.28, 0.63) , P< 0.0001] . Meanwhile, the re-tear rate of large to massive rotator cuff tear after repair was also significantly reduced [OR = 0.28, 95% CI (0.13, 0.58) , P = 0.0007] . In terms of shoulder VAS score [SMD = -0.63, 95% CI (-1.40, 0.14) , P = 0.11] , range of motion (ROM) external rotation [SMD = 0.05, 95% CI (-0.22, 0.32) , P = 0.70] ; anteflexion [SMD = 0.10, 95% CI (-0.17, 0.37) , P = 0.47] , shoulder function CMS score [SMD = 0.12, 95% CI (-0.09, 0.32) , P = 0.26] , UCLA score [SMD = -0.04, 95% CI (-0.29, 0.21) , P = 0.76] , ASES score [SMD = -0.06, 95% CI (-0.33, 0.21) , P = 0.67] , and DASH score [SMD = -0.15, 95% CI (-0.43, 0.13) , P = 0.29] , there was no statistical difference.

Compared with simple rotator cuff repair, rotator cuff repair combined with bone marrow stimulation technology can significantly improve the rotator cuff repair capability. It is particularly noteworthy that this technology can promote the healing of large to massive rotator cuff tear, and there was no significant difference in postoperative shoulder pain, ROM and function.