Optimum tension for the bridging sutures in trans-osseous equivalent rotator cuff repair -cadaveric biomechanical study-

Abstract

Background: Transosseous-equivalent (TOE) rotator cuff repair can increase contact area and contact pressure between the repaired cuff tendon and bony footprint and show higher ultimate load to failure and smaller gap formation compared with other repair techniques. However, it has been suggested that medial rotator cuff failure after TOE repair may result from increased bridging suture tension.

Purpose: To determine optimum bridging suture tension in TOE repair by evaluating footprint contact and construct failure characteristics at different tensions.

Study Design: Controlled laboratory study.

Methods: Eighteen fresh-frozen cadaveric shoulders, randomly divided into 3 groups, were constructed with TOE configuration using the same medial suture anchor, placing a Tekscan sensing pad between repaired cuff tendon and footprint. Nine of the 18 shoulders were used to measure footprint-contact characteristics. Using the Tekscan measurement system, contact pressure between the rotator cuff tendon and greater tuberosity was quantified for bridging suture tensions of 60, 90, and 120 N at glenohumeral abduction angles of 0° and 30° and humeral rotation angles of −30°, 0°, and +30°. TOE constructs of all 18 shoulders then underwent cyclic-loading and load-to-failure tests. Yield load, ultimate load, stiffness, hysteresis, strain, and failure mode in construct-failure tests (cyclic-loading and load-to-failure tests) were evaluated in 3 groups: 2 Versalok tension groups (60 and 120 N) and a maximum tension of other type lateral anchor group.

Results: As bridging suture tension increased, contact force, contact pressure, and peak pressure increased significantly at all positions (all P < .05). However, regarding contact area, no significant differences were found between 90 and 120 N at all positions, although there were significant differences between 60 and 90 N. From the construct failure test, there were no significant differences in any parameters according to various tensions or anchor types (all P > .05).

Conclusion: Increasing bridging suture tension over 90 N did not improve contact area but did increase contact force and pressure. Bridging suture tension did not significantly affect ultimate failure loads.

Clinical Relevance: Considering risks for over-tensioning of bridging sutures, it might be clinically more relevant to not set the bridging suture tension over 90 N.