Can a Two Simple Stitches Method Provide Secure Fixation Strength in Biceps Tenodesis?: Biomechanical Evaluation of Various Suture Techniques

BackgroundThe purpose of this study was to compare the initial fixation strength between four different suture methods for the long head of the biceps. MethodsForty-eight fresh frozen porcine flexor hallucis longus tendons (mean width at suture site, 8.5 ± 0.9 mm) and phalanx bones were randomly assigned to one of the four arthroscopic biceps tenodesis techniques: simple stitch (SS), mattress suture (MS), lasso-loop (LL), and two simple stitches (2SS). A biceps tenodesis was performed according to the four techniques using all-suture type suture anchors (1.9-mm SUTUREFIX anchor with No. 1 ULTRABRAID sutures). Biomechanical evaluations were performed to test load to failure (N), stiffness (N/mm), stress (N/m2), and mode of failure. ResultsAs for the SS, MS, LL, and 2SS, the mean load to failure was 50.9 ± 14.61 N, 82.3 ± 24.8 N, 116.2 ± 26.7 N, and 130.8 ± 22.5 N (p < 0.001), respectively; mean stiffness was 6.1 ± 1.3 N/mm, 6.7 ± 2.6 N/mm, 7.8 ± 1.4 N/mm, and 8.1 ± 4.2 N/mm, respectively (p = 0.258); and mean stress was 0.7 ± 0.3 N/m2, 1.4 ± 0.8 N/m2, 2.9 ± 0.7 N/m2, and 2.7 ± 0.8 N/m2, respectively (p < 0.001). All the failures happened by the suture cutting through the tendon along its longitudinal fibers. ConclusionsNeither the SS nor the MS method was enough to securely fix the biceps tendon with a significantly lower mechanical strength; however, the 2SS method showed similar initial fixation strength as the LL technique.