Multiple Channeling Improves the Structural Integrity of Rotator Cuff Repair

Background: Multiple channeling is a straightforward additional procedure for rotator cuff repair that creates multiple channels in the greater tuberosity, through which bone marrow of the proximal humerus communicates with the repair site. Purpose: To investigate the effect of multiple channeling on clinical and structural outcomes of arthroscopic rotator cuff repair. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 124 patients with a full-thickness rotator cuff tear were included in the study. Fifty-seven patients underwent arthroscopic rotator cuff repair with multiple channeling (the multiple channeling group) and 67 without it (the conventional group). Analysis of surface markers was performed to characterize the cells recruited by multiple channeling using flow cytometry. Clinical outcomes were evaluated preoperatively and at a minimum of 2 years after surgery (average, 36.79 13.69 months) with respect to pain, range of motion, muscle strength, overall satisfaction, and commonly used functional scores. At a minimum of 9 months after surgery, structural integrity was assessed by magnetic resonance imaging or computed tomography arthrography. Results: Mesenchymal stem cells (MSCs) positive for CD73, CD90, and CD105 and negative for CD45 could be isolated and cultured from bone marrow mononuclear cells of the proximal humerus. Clinical outcomes, including pain, range of motion, strength, overall satisfaction, and functional scores, showed no statistical difference between the 2 groups (all P > .05). The retear rate of the multiple channeling group (22.2%) was significantly lower than that of the conventional group (45.2%) (P = .023). Conclusion: The findings of the study showed that multiple channeling significantly decreased the retear rate after arthroscopic rotator cuff repair, probably via the recruitment of endogenous MSCs from the proximal humerus. Although the results did not show significant differences in the clinical outcomes between the 2 groups, better clinical outcomes might be anticipated in the multiple channeling group via improved structural integrity in a long-term follow-up.