The Fate of Sutures Post Rotator Cuff Repair.

Abstract Background Ultrasound imaging has been widely used as a diagnostic tool for rotator cuff tears. Several studies have explored the changes in rotator cuff tendon morphology after arthroscopic cuff repair, however none have addressed the fate of sutures. The aim of this study was to determine: (1) if the sutures migrate through the tendon during the postoperative healing period in patients who have had arthroscopic rotator cuff repair, (2) if the sutures do migrate, the time point at which it does and, (3) if the quality of the tendon, in terms of tendon stiffness, modulus of elasticity, bursal thickness and anatomical footprint, affects suture migration. Methods This was a prospective study involving 21 patients who had primary arthroscopic rotator cuff repair performed by a single surgeon. All patients were assessed at 8 days, 6 weeks, 12 weeks and 24 weeks post-repair; during each assessment, patients underwent an ultrasound examination (using a Siemens ACUSON S2000™ ultrasound system, following a standardized protocol), where supraspinatus tendon thickness and thickness of tendon tissues below and above the suture were measured. Measurements of anatomical footprint, bursal thickness, tendon stiffness and modulus of elasticity were obtained to assess tendon quality. Results Out of the 21 participants, 14 (67%) had full thickness tears and 7 (33%) had partial thickness tears. Between the 12th and 24th week follow-up, 2 patients’ tendons were found to be not intact. Within the first 12 weeks of the post-repair healing period, the sutures migrated inferiorly, through to the middle of the tendon at the footprint-articular junction (i.e., ratio of tendon tissue thickness below the suture to the total tendon thickness = 0.5) (p=0.03). The mean anatomical footprint increased from 8.4 ± 1.6mm to 9.1 ± 1.2mm between 8 days and 6 weeks (p=0.04); bursal thickness decreased during the 24-week period from 1.5 ± 0.9mm to 0.7 ± 0.4mm (p=0.005); tendon modulus of elasticity increased from 154 ± 75 kPa to 205 ± 96 kPa between 8 days and 24 weeks (p=0.05). Discussion This is the first study to investigate suture position and migration post arthroscopic rotator cuff repair. The findings of this study suggest that sutures migrating to the middle of the tendon during the postoperative healing process is a normal phenomenon observed on ultrasound. Level of Evidence: Level IV; Case Series; Treatment Study;