A Tensionable Method for Subscapularis Repair after Shoulder Arthroplasty.

Background: This study compared the biomechanical properties of a new lesser tuberosity (LTO) repair with a tensionable construct with suture tape and preplaced racking hitches vs. a traditional LTO repair using 4 high-strength sutures. The hypothesis was that there would be no difference between the 2 constructs.

Methods: LTO repairs were performed on 6 matched, paired cadaveric shoulders after placement of an uncemented humeral stem. The LTO in group 1 was repaired with 4 high-strength #2 sutures, each passed individually through the subscapularis tendon. The LTO in group 2 was repaired with 2 suture tape loops with a preplaced racking hitch knot and 2 passes through the subscapularis tendon. All sutures were passed around the humeral stem before passing through the subscapularis tendon. The specimens then underwent cyclic displacement and load-to-failure testing.

Results: Load to failure was 209.6 ± 71.2 N in group 1 compared with 502.8 ± 168.6 N in group 2 ( = .018). There was no difference in displacement between the 2 groups. All failures in group 1 occurred by knot slippage. The mode of failure in group 2 was tendon tearing in 5 of 6 cases.

Conclusion: A simplified LTO repair with suture tape and compression bridge and a preplaced half racking knot achieves favorable biomechanical properties in a technically efficient manner that may be useful clinically.