Biomechanical study on arthroscopic biceps tenodesis fixation techniques

• Main Author: Lim, Gideon Boon Hao
• Other Authors: Chou Siaw Meng
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/141264
• Institution: Nanyang Technological University

Biceps tenodesis is one of the common and appropriate treatment options for patients with lesion of the Long Head of the Biceps Tendon (LHBT). Arthroscopic intra-articular tenodesis of the LHBT is a safe technique to treat biceps tendon injuries. The interference screw fixation used in the procedure is said to provide stiffer construct but fails catastrophically in osteoporotic bones. Thus, it is important to find the best repair technique among the two different techniques through biomechanical experiments. The objective of the study is to determine the ultimate failure load and cyclical displacement of the interference screw fixation and the lasso-loop suture anchor technique in arthroscopic intra-articular biceps tenodesis. Four sheep humerus and front leg specimens were used in the experiment, with two repaired with the BIORCI – HA Bioabsorbable Interference Screw and the remaining with TWINFIX Ultra PK 4.5 mm Suture Anchor. Two specimens for each technique were mounted onto a custom-designed fixture and secured onto the Instron 5566 machine. Specimens were subjected to cyclical loading between 5 N and 70 N at 8.33 mm/s (1 Hz) for 500 cycles. During cyclic loading, the peak cyclic displacement was measured every 100 cycles until it reaches 500 cycles. All specimens for each technique which had not failed during cyclic loading were then loaded to failure. The mean cyclic displacement, ultimate failure load and stiffness are 3.88 ± 1.71 mm, 93.44 ± 28.53 N and 9.23 ± 1.73 N/mm for the interference screw fixation technique and 2.11 ± 0.82 mm, 199.37 ± 4.72 N and 13.60 ± 0.93 N/mm for the lasso-loop suture technique respectively. The mode of failure for the specimens included suture pull-out due to tearing of tendon and tendon pulling out from interference screw. Comparing the results, the lasso-loop suture technique had shown lower cyclic displacement, higher ultimate failure load and stiffness than the interference screw technique.