Studies covering biomechanical properties of arthroscopic suprapectoral biceps tenodesis using interference screw or suture anchor are published in the literature but they are limited to a small sample sizes. The purpose of this study was to assess and compare the biomechanical properties and load-to-failure (LTF) of 2 arthroscopic suprapectoral biceps tenodesis fixation techniques, interference screw (IS) fixation and double-loaded suture anchor (SA) fixation.
Materials And Methods
39 human cadaveric shoulders were randomized into two treatment groups. 20 shoulders received an IS and 19 SA. A biceps tenodesis was performed according to the techniques listed above. Cyclic loading tests on a dynamic-loading testing device were used to measure and compare the resistance to failure pull-out between the two groups. Hartley's Fmax test and Tukey's Honest Significant Difference method were used for statistical analysis.
In IS group the minimal LTF was six cycles at 100 N and maximum LTF 20 cycles at 200 N while in SA group the minimal LTF was nine cycles at 100 N and maximum LTF 77 cycles at 200 N. SA showed increasing (though not significant) resistance, comparing to screws (diff=7.04, lwr=-2.35, upr=16.43, p=0.1768), where eight of them reached 200 N load before failure whereas in IS fixation only three reached it. The IS group failed due to a complete tendon tearing at the bone-tendon-screw interface while the SA group failed at the suture-tendon interface due to slippage of lasso loop.
Based on these results, a biceps tenodesis using an IS or a SA technique will provide a similar fixation strength. The surgeon treating biceps tenodesis should expect similar initial strength using an IS or double-loaded SA.