Mechanical strength of four different biceps tenodesis techniques

Purpose: The aim of this study was to compare the biomechanical properties of 4 different biceps tenodesis techniques. Type of Study: Biomechanical experiment. Methods: Four groups of fresh sheep shoulders (28 total) with similar shape characteristics were used. Biceps tenodesis was performed using the following techniques: group I (n = 7), tunnel technique; group 2 (n = 7), interference screw technique; group 3 (n = 7), anchor technique; and group 4 (n = 7), keyhole technique. Each construct was loaded to failure and the groups were compared with respect to maximum load in Newtons and deflection at maximum load in millimeters. The results were statistically analyzed with 1-way analysis of variance, the Bonferroni post hoc test and the Student t test or the nonparametric Mann-Whitney U test. Results: The calculated average maximum loads were 229.2 +/- 44.1 N for the tunnel technique, 243.3 +/- 72.4 N for the interference screw, 129.0 +/- 16.6 N for the anchor technique, and 101.7 +/- 27.9 N for the keyhole technique. Statistical testing showed no statistically significant differences between groups 1 and 2, groups 3 and 4, or groups 2 and 3 with respect to maximum load and deflection at maximum load (P =.09/P = .49, P =.41/P =.79, and P =.06/P =.82 for load/deflection in the 3 comparisons, respectively). However, all other group comparisons revealed significant differences for both parameters (group 1 nu group 4 [P < .01/P < .01]; group 1 nu group 3[P < .01/P =.01]; and group 2 nu group 4 [P =.007/P =.003]). Conclusions: The strongest construct was made with the interference screw technique, followed by the tunnel, anchor, and keyhole techniques. There were no statistically significant differences between the interference screw and tunnel techniques with respect to maximum load or deflection at maximum load. Clinical Relevance: Although it is difficult to extrapolate in vitro data to the clinical situation, the interference screw technique has better initial biomechanical properties and may produce improved clinical outcomes.