Evaluation Of A Novel Curved Intramedullary Button Versus Traditional Flat Button For Proximal Biceps Tenodesis: A Biomechanical Study

Aim
The purpose of this study is to test the biomechanical performance of a novel curved intramedullary button for proximal biceps tenodesis in comparison to a standard flat unicortical button. The novel curved button enables inlay tendon fixation without the need for bicortical drilling and is therefore anticipated to lessen the likelihood of gap formation, thereby potentially improving tendon-bone healing, while minimizing the risk of neurologic injury.
Background
Long head biceps tendon pathology is a common cause of shoulder pain. One of the surgical strategies for the management of this condition is biceps tenodesis, often used in young athletes. Variations in the biceps tenodesis fixation techniques have been evaluated by different biomechanical studies. However, the results of these studies are inconsistent, leading to a lack of consensus on the optimal technique.
Therefore, it is crucial to identify an effective and reliable technique for proximal
Methods
A total of 16 cadaveric fresh-frozen shoulders were randomly allocated to undergo proximal biceps tenodesis using either a standard flat unicortical button or the new curved button. Following the tenodesis, each shoulder was dissected down to the humerus, leaving the biceps tendon intact for biomechanical testing. The biceps tendon was initially subjected to a cyclic load, ranging from 5 to 100N, at a frequency of 2.5 Hz for a total of 1000 cycles. After this, the force applied to the tendon
Results
All 16 specimens were included in the data analysis. No failure occurred during cyclic testing. After cyclic testing the median displacement was 10.4 mm (6.1 – 16,1) for the group with curved button and 11.9 mm (6.0 – 43.9) for the group with flat button (p=.721). The ultimate load-to-failure for the curved button group was 239.4 ± 35.1 N, while the flat button group averaged 227.0 ± 42.0 N (P = .534).
Stiffness was 70.0 ± 10.3 N/mm for the curved button group and 61.3 ± 17.3 N/mm for the flat
Conclusion
The novel curved and standard flat button exhibited similar biomechanical properties in terms of displacement, load-to-failure, and stiffness. Considering these results and the theoretical advantages of the new curved button, this technique could be a promising alternative for the treatment of proximal long head biceps tendon pathology.