طراحي و مدل‌سازي پچ چسبنده براي ترميم پارگي تاندون روتاتوركاف به‌كمك روش المان‌محدود

Design an‎d Modeling of Adhesive Patch for Rotator Cuff Tendon Tear Repair using Finite Element Method

مهندسي پزشكي

Shoulder injuries are the third most common musculoskeletal injuries. Rotator cuff tears are the most common age-related injury an‎d disability in people over 45, leading to pain an‎d discomfort, decreased function, an‎d reduced range of motion. Suture-based repair methods have a high re-tear rate of 94% after several years. If partial tears are not repaired, they progress to full-thickness tears over time. Due to the high rate of tendon re-tears an‎d the inefficiency of current repair methods, a new an‎d more effective sutureless method is needed to attach the tendon to the bone that can withstan‎d daily loading. In this study, a three-dimensional finite element model of the scapula, humerus, an‎d tendon was created from CT scan images, an‎d then a rectangular adhesive repair patch was designed on the tendon an‎d humerus. By modeling the adhesive region, the adhesive strength of this adhesive was investigated. The parameters of the adhesive region model, including interfacial strength, penalty stiffness, an‎d fracture energy, were separately investigated while keeping the other two parameters constant during three movements: 60-degree abduction, flexion, an‎d 45-degree rotation, to find suitable properties with high adhesion an‎d resistance during these three movements. Output parameters of damage in Abaqus finite element software, including damage initiation an‎d patch separation an‎d damage progression, were extracted an‎d analyzed. The results showed that the patch with a fracture energy higher than 100 J/m2 an‎d a cohesive strength between 1.14 an‎d 10 MPa maintained its adhesion to the tendon an‎d bone during flexion an‎d abduction movements an‎d did not separate. This value was higher for the shoulder internal rotation movement. In the internal rotation movement, the patch had good adhesion to the tendon an‎d bone with a cohesive strength between 1.8 an‎d 10 MPa an‎d a fracture energy higher than 500 J/m2. Materials with higher modulus an‎d stiffness resulted in less force transfer. Patch failure an‎d damage were higher in materials with high shear modulus. Shear modulus between 0.5 an‎d 7.6 MPa for abduction, between 0.5 an‎d 11 MPa for flexion, an‎d between 0.5 an‎d 1.5 MPa for internal rotation was considered a suitable stiffness. The accuracy an‎d validity of the damage evolution output parameter with changes in the modeling parameters of the adhesive region were investigated using Pearson an‎d Spearman statistical tests, an‎d the correlation coefficient of the parameters was expressed. Based on the results obtained from patch damage an‎d separation an‎d the proposed range, bio-derived adhesives such as DOPA, organophosphates, commercial cyanoacrylate-based adhesives, elastomers, injectable bioceramics, an‎d porous epoxy adhesives an‎d 3,4-dihydroxyphenyl chitosan are suitable materials with adhesive strength in the range of 1.8 to 10 MPa in three movements of abduction, flexion, an‎d internal rotation. Adhesive patches modeled with the finite element method introduced a novel sutureless method with suitable adhesive strength for attachment to the tendon an‎d bone. The results of this study provided significant assistance to researchers an‎d physicians in selec‎ting materials with adhesion capability in the bodyʹs biological environment for tendon repair, considering daily shoulder movements, including abduction, flexion, an‎d internal rotation.

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