Reconstruction of a long head biceps using Bashti method; comparison between two different insertion techniques

Abstract

The Long Head Biceps (LHB) is one of the most vulnerable tendons in the human body, and its damage can cause problems for the patient, such as limitation of arms ability to motion, severe pain and reducing the strength of arm. The complete tear of the LHB may need a surgical treatment. Although, the existing surgical method can reattach the tear tendon but there are demands to improve the conventional LHB reconstruction methods. Bashti Bone Plug Technique (BBPT) is an implant-less surgical technique. The method can improve the quality of LHB surgical treatment. The purpose of this study is to investigate the effect of insertion techniques on biomechanical properties of the Bashti fixation method. The study uses bovine tendons and artificial Sawbones blocks with the density of 15 pcf correlated to the density of a young human radius bone. These specimens allocated into two groups with an equal number of samples. In the first group, the insertion process was performed using a manual hammer where the impacts' frequency was uncontrolled. In the second group, the samples were inserted using an automatic hammer with a constant and controlled frequency of 3600 beats per minute (BPM). All other conditions, including geometry of the samples, were the same for all specimens in both groups. After the sample preparation, samples were tested under a poll-out test. All samples were subjected to a cyclical test followed by a single cycle load to failure test. The cyclical test performed using preconditioning to adjust the setup and a periodic load between 10 N and 70 N, for 100 cycles. The rate of loading was 500 mm per minutes. Immediately after completing the cyclical test, the samples loaded under a simple tensile loading with the same loading speed until a fixation failure. Considering the experimental outcome, for the first group, the average maximum tensile strength was 235±39.4 N and the average stiffness was 9.25±2.12 N/mm, while for the second group the average maximum tensile strength was 163±54.5 N and the average stiffness was 8.46±4.9 N/mm. The study firstly proven that Bashti reconstruction method is a suitable method to fix LHB. In addition, it was concluded that the insertion technique has a significant effect on the maximum tensile strength of the Bashti fixation method. Further study on effect of insertion frequency is ongoing. Please note this paper originally written in Farsi language. The full paper is attached.