Biomechanical Analysis of Lark-Loop, Lasso-Loop and Krackow Suture Technique in Tenodesis

Strong tendon grasping is vital to the success of a tenodesis operation. The purpose of this study was to evaluate the initial tendon-fixation strength of the Lark-Loop technique in arthroscopic suprapectoral biceps tenodesis and compare it with others commonly used techniques.

Thirty-three porcine superficial flexor digitorum tendons were harvested from a local slaughterhouse and randomly divided into three groups to perform three tendon fixation techniques (Lasso-Loop stich group, Lark-Loop stich group or Krackow stich group; 11 tendons each group) with a No. 2 suture, respectively. Each tendon was pre-tensioned in 5°N for 2 min and then cyclically loaded 5 to 30°N for 500 cycles to assess displacement. After cyclic loading, the tendon was loaded to ultimate tendon-suture configuration failure at the rate of 1 mm/s. Finally, the mode of failure and the construct stiffness of the tendon were recorded and calculated.

After cyclical loading, the displacement of the Lark-Loop group was equivalent to the Krakow group (P > 0.9999) but significantly smaller than the Lasso-Loop group (P = 0.0009). The ultimate load to failure for the Lark-Loop was equivalent to the Krakow technique group (P = 0.1463) but significantly greater than the Lasso-Loop group (P < 0.0001). The stiffness for the Lark-Loop was equivalent to the Krakow group (P = 0.4718) but significantly greater than the Lasso-Loop technique group (P < 0.0001). In the Lark-Loop and Krackow group, all the tendons failed by suture breakage, while all the tendons failed by suture cutting through the tendon in the Lasso-Loop technique group.

Lark-Loop suture technique has biomechanical properties comparable to Krackow and superior to the Lasso-Loop in terms of suture displacement, ultimate load to failure, and stiffness. Therefore, the Lark-Loop suture fixation technique may be beneficial for arthroscopic biceps tenodesis.