The optimum tension for bridging sutures in transosseous-equivalent rotator cuff repair: a 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 can show higher ultimate loads 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: A total of 18 fresh-frozen cadaveric shoulders, randomly divided into 3 groups, were constructed with a TOE configuration using the same medial suture anchor and placing a Tekscan sensing pad between the repaired rotator cuff tendon and footprint. Nine of the 18 shoulders were used to measure footprint contact characteristics. With use of the Tekscan measurement system, the contact pressure and area between the rotator cuff tendon and greater tuberosity were quantified for bridging suture tensions of 60, 90, and 120 N with glenohumeral abduction angles of 0° and 30° and humeral rotation angles of 30° (internal), 0°, and 30° (external). TOE constructs of all 18 shoulders then underwent construct failure testing (cyclic loading and load to failure) to determine the yield load, ultimate load, stiffness, hysteresis, strain, and failure mode at 60 and 120 N of tension.

Results: As bridging suture tension increased, contact force, contact pressure, and peak pressure increased significantly at all positions (P < .05 for all). 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. The construct failure test demonstrated no significant differences in any parameters according to various tensions (P > .05 for all).

Conclusion: Increasing bridging suture tension to 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 the risks of overtensioning bridging sutures, it may be clinically more beneficial to keep bridging suture tension below 90 N.

Keywords: bridging suture tension; construct failure; footprint contact characteristics; rotator cuff; transosseous-equivalent repair.