Biomechanical comparison of novel ulnar collateral ligament reconstruction with internal brace augmentation vs. modified docking technique.

Abstract

Ulnar collateral ligament (UCL) reconstruction (UCLR) is a common surgery among baseball pitchers. UCL repair combined with augmentation using high-strength tape, referred to as an internal brace, was developed as an alternative to UCLR in select patients with the benefit of allowing these athletes to return to sport (RTS) faster. A combined UCLR with an internal brace may allow players indicated for a UCLR to RTS more expeditiously. Twenty-four cadaveric elbows were divided into 3 groups: 12 specimens into the modified docking (MD) group, 6 into the double-docking (DD) group, and 6 into the double docking with internal brace augmentation (DDA) group. This allowed a 1:1 comparison of the MD to the DD and the MD to the DDA. Valgus cyclic testing of native and reconstructed specimens was executed at 90° elbow flexion. After preconditioning, all specimens were cycled between 2 and 10 Nm for 250 cycles. Reconstructed specimens continued to a torque test to catastrophic failure step. Outcome data included intracyclic stiffness, maximum cyclic rotational displacement, gap formation, and failure torque. Cyclic stiffness of the constructs remained constant throughout the entirety of the torque-controlled cycling phase. The DDA group resulted in a 38% increase in cyclic stiffness from native testing (not statistically significant) and a statistically significant 54% increase from the MD (P=.002). The DDA mean cyclic stiffness was significantly greater than the Native (P<.001), DD (P=.025), and MD (P<.001) groups. Between reconstruction groups, mean gap formation was greatest among the MD group (2.51°±1.59°) and least for the DDA group (1.01°±0.57°) but did not reach statistical significance. Tape augmentation to the modified UCLR (DDA group) improved cyclic stiffness and reduced gap formation compared with the MD group.