Clinical outcomes and repair integrity of arthroscopic rotator cuff repair using suture-bridge technique with or without medial tying: prospective comparative study.

BACKGROUND: There have been few studies comparing clinical and radiological outcomes between the conventional and knotless suture-bridge techniques. The purpose of this study was to evaluate and compare the functional outcomes and repair integrity of arthroscopic conventional and knotless suture-bridge technique for full-thickness rotator cuff tears. METHODS: We prospectively followed 100 consecutive patients (100 shoulders) with full-thickness rotator cuff tears treated with the arthroscopic conventional or knotless suture-bridge technique from October 2012 to July 2014. Enrolled patients returned for follow-up functional evaluations at 1 and 2 years after the operation. There were four outcome measures in this study: American Shoulder and Elbow Surgeons (ASES) scores, Shoulder Rating Scale of the University of California at Los Angeles (UCLA) scores, Constant scores, and visual analog scale (VAS) pain scores. Enrolled patients returned for follow-up magnetic resonance imaging or ultrasonography evaluation to confirm the integrity of the repaired cuff at 6 months post-operation (97% follow-up rate). Also, we investigated the preoperative cuff retraction of enrolled patients using preoperative MRI to find out correlation between the stage of cuff retraction and re-tear rate. RESULTS: At final follow-up, the average UCLA, ASES, Constant, and VAS scores had improved significantly to 32.5, 88.0, 80.4, and 1.3, respectively, in the conventional suture-bridge technique group and to 33.0, 89.7, 81.2, and 1.2, respectively, in the knotless suture-bridge technique group. The UCLA, ASES, Constant, and VAS scores improved in both groups after surgery (all p < 0.001), and there were no significant differences between the two groups at 2-year follow-up (p = 0.292, 0.359, 0.709, and 0.636, respectively). The re-tear rate of repaired rotator cuffs was 16.3% (8/49 shoulders) in the conventional suture-bridge technique group and 29.2% (14/48 shoulders) in the knotless suture-bridge technique group; this difference was not significant (p = 0.131). There were no significant differences between the re-tear rate of the two groups in the Patte stage I and II (p = 0.358 and 0.616). CONCLUSIONS: The knotless suture-bridge technique showed comparable functional outcomes to those of conventional suture-bridge techniques in medium-to-large, full-thickness rotator cuff tears at short-term follow-up. The knotless suture-bridge technique had a higher re-tear rate compared with conventional suture-bridge technique, although the difference was not significant.

Tight medial knot tying may increase retearing risk after transosseous equivalent repair of rotator cuff tendon.

BACKGROUND: Retearing mechanism after transosseous equivalent (TOE) rotator cuff repair has not been fully clarified yet. OBJECTIVE: The purposes of this study were to compare the stress distribution pattern in the tendon stump between knotted and knotless TOE repair and to investigate the role of suture tension applied during medial knot tying using a 3-dimensional finite element (3D-FE) method. METHODS: Both knotted and knotless TOE repairs were simulated on the 3D-FE human rotator cuff tear model. Elastic analysis was performed to compare the stress distribution pattern inside the tendon between the two models. The amount of compressive load applied to the medial-row sutures was then changed as 0, 20, 40, 60, 80, and 100 N in the knotted model. RESULTS: Knotted model demonstrated more distinct stress concentration inside the tendon around medial-row sutures than the knotless model. Mean von Mises equivalent stress in this area in the 0, 20, 40, 60, 80, and 100 N models was 0.26, 0.35, 0.50, 0.70, 1.11, and 1.14 MPa, respectively. CONCLUSIONS: In the knotted TOE repair, tight medial knot tying might cause a high stress concentration around medial knots, which may constitute one of the pathogenetic factors of postoperative retearing at this site.