Suture Technique Influences the Biomechanical Integrity of Pectoralis Major Repairs

Suture Technique Influences the Biomechanical Integrity of Pectoralis Major Repairs Background: Multiple surgical techniques exist for repair of pectoralis major tendon ruptures. These repair constructs commonly fail from suture breakage or pull-out. To our knowledge, no data exists on the optimal suture configuration for maximizing construct strength. In this study, we compare the biomechanical characteristics of four suture repair techniques. Furthermore, the biomechanical performance of repaired pectoralis major tendons are compared to intact native tissue. Hypothesis: We hypothesize that changes in the number of sutures crossing the repair site, the suture configuration, or the suture material will increase biomechanical integrity compared to a baseline control group. In addition, all repaired tendons will have a lower biomechanical profile compared to the intact native attachment. Methods: 40 fresh-frozen cadaveric shoulders were randomized to four equal groups. All specimens were repaired using endosteal Pec Buttons. The control group was repaired with #2 polyblend suture in a modified Mason-Allen stitch configuration. The “triple” group used #2 suture in a modified Mason-Allen stitch configuration with triple-loaded buttons. The “configuration” group used #2 suture in a Krackow configuration with an overlying Bunnell stich. The “tape” group used 2mm-width polyethylene tape in a Krackow configuration and #5 polyblend suture in an overlying Bunnell stitch. All specimens were tested under cyclic loading and load-to-failure protocols with optical marker data simultaneously collected. Results: Under cyclic loading, there was no significant difference between any of the repair groups. Under pull-to-failure testing, the tape group withstood a significantly greater maximum load than the groups repaired with Mason-Allen stitches. The configuration group failed via suture rupture in 90% of specimens whereas the other groups failed predominantly via suture pull-out through the tendon. There were significant differences for both cyclic and pull to failure tests between the intact native tissue and all four repair techniques. Conclusions: Although repaired tendons are found biomechanically inferior to native intact tissue, suture technique can improve the biomechanical performance of pectoralis major repairs by preventing suture pull-out from tendon at lower loads. As loads increase, suture breakage may occur unless robust suture such as polyethylene tape and No. 5 polyblend are used (tape group).