Biomechanical performance of three suture fixation techniques for proximal biceps tenodesis: a human cadaveric study

OBJECTIVES: To compare the biomechanical properties of the lark loop and 360 double-lasso loop techniques with the double Krackow stitch for proximal biceps tenodesis using human cadaveric long head biceps tendons.

METHODS: Thirty fresh-frozen human shoulders were randomly allocated to three groups to undergo the 360 double-lasso loop, the lark loop or the double Krackow proximal biceps tenodesis. Following the tenodesis, the construct was subjected to a cyclic loading from 5 to 30 N, at a frequency of 2 Hz for a total of 500 cycles. Then the tendon was loaded to failure. During testing, total displacement, suture displacement, tendon displacement, ultimate failure load, stiffness, and modes of failure were evaluated.

RESULTS: All 30 specimens were included in the data analysis. One tendon (10%) failed during cyclic testing of the 360 double-lasso loop constructs. No failure during cyclic testing occurred in the other groups. After cyclic testing, the mean displacement was 5.5 ± 1.9 mm for the double Krackow stitch group, 6.6 ± 2.1 mm for the 360 double-lasso loop group, and 5.2 ± 1.8 mm for the lark loop group. The double Krackow stitch group exhibited a mean load-to-failure of 138.7 ± 24.5 N, the 360 double-lasso loop group failed at a mean of 102.5 ± 45.0 N and the lark loop group failed at an average of 166.9 ± 59.7 N. There was a statistically significant difference in load-to-failure between the suture techniques (F (2, 26) = 4.755, p = 0.017).

CONCLUSION: In this in-vitro biomechanical study, the lark loop suture technique demonstrated a higher load-to-failure, greater stiffness, and a different failure mechanism compared to the 360 double-lasso loop and double Krackow stitch constructs, suggesting that it may offer a more secure time-zero fixation and may be more resilient to unexpected early loading events. Further clinical research is warranted to determine whether these biomechanical advantages translate to better patient outcomes.

LEVEL OF EVIDENCE: Level V, Basic Science Study; Biomechanics.