Greater tuberosity bone mineral density and rotator cuff tear size are independent factors associated with cutting-through in arthroscopic suture-bridge rotator cuff repair

Purpose: To evaluate the correlation between cutting-through at the greater tuberosity (GT) in arthroscopic suture-bridge rotator cuff repair and the bone mineral density (BMD) of the lumbar spine, hip and ipsilateral GT of the proximal humerus and to evaluate factors and clinical outcomes related to cutting-through.

Methods: This study prospectively enrolled patients who underwent arthroscopic knotted suture-bridge rotator cuff repair for full-thickness rotator cuff tears between June 2014-October 2015 and who had undergone dual energy X-ray absorptiometry (DEXA) scans within 1 month before surgery with a minimum 2-year follow-up. Cutting-through was defined as the occurrence of cortical breakage of the GT just medial to the lateral knotless anchor hole due to the tension of the sutures from the medial anchor, and it was assessed. Clinical and radiological data were analyzed. Univariate and regression analyses were performed to evaluate factors related to cutting-through.

Results: A total of 78 patients were analyzed. Patients were divided into two groups: patients who had cutting-through (46, group I) and patients who did not (32, group II). In an analysis of lumbar spine, hip, and GT BMD, GT BMD was the most effective for predicting cutting-through (AUROC=0.94, 95% CI; 0.89-0.99). GT BMD (P<0.001) and tear size (P=0.004) were independent factors for cutting-through. Although a significant difference was found between the two groups in terms of age, sex, lumbar spine and hip BMD, fatty infiltration of the supraspinatus and infraspinatus, and atrophy of the supraspinatus, these variables were not independent factors. Clinical and structural outcomes showed no significant difference between the two groups, and anchor failure was not identified intraoperatively.

Conclusions: GT BMD and rotator cuff tear size are independent factors associated with cutting-through at the GT. A DEXA scan of the proximal humerus is useful for predicting bone quality before arthroscopic suture-bridge rotator cuff repair.

Level of evidence: Level II, Prospective cohort study.