The double-lasso loop technique of Biceps tenodesis has lower displacement after cyclic loading,compared to interference screw fixation: Biomechanical analysis in an ovine model

Abstract

Background

Biceps tenodesis is an effective treatment for symptomatic long head of biceps tendon pathology. Recently the arthroscopic “double lasso-loop” suture anchor (DLSA) technique was described, advantaged by reduced cost, complexity, and operative time. We aimed to compare the in vitro strength of DLSA with conventional interference screws (IS).

Methods

A biomechanical analysis was conducted on 14 sheep shoulders (8 DLSA, 6 IS), consisting of a 500-cycle cyclic loading experiment of 5–70 N and ultimate failure load (UFL) test where each specimen was pulled until failure. Displacement (mm) was recorded every 100 cycles, while stiffness and UFL were observed.

Results

Cyclic displacement was significantly lower with DLSA at 100 cycles, but not above. During the UFL test, IS was stiffer (27.68 ± 6.56 N/mm versus 14.10 ± 5.80 N/mm, p = .005) and had higher UFL (453.67 ± 148.55 N versus 234.22 ± 44.57 N, p = .001) than DLSA. All DLSA failures occurred with suture/anchor pull-out, while all IS constructs failed at the muscle/tendon.

Discussion

Comparison of the novel DLSA technique with a traditional IS method found lower initial displacement. While our IS constructs could withstand higher UFL, peak load characteristics of DLSA were similar to previous ovine studies. Hence, the DLSA technique is a viable alternative to IS for biceps tenodesis with its purported non-biomechanical advantages.