Date of Award
Master of Science (MS)
Tears to the rotator cuff often require surgical repair. These repairs often culminate in re-tearing when sutures break through the tendon in the weeks following repair. Numerous studies have been performed to identify suturing strategies that reduce this risk by balancing forces across sutures. However, the structural engineering basis for these approaches is still emerging, and the effects of tendon mechanics on load balancing is still unclear. Specifically, the effects of the viscoelastic nature of tendon on load sharing have not been established. With the aim of providing insight into this problem, this thesis studies how tendon viscoelasticity, tendon stiffness, and structural features such as the spacing of suture anchors affects the balance of forces across sutures. A discrete shear lag approach was developed, and the equations were solved numerically. Results from a model, three-row sutured re-attachment demonstrated that optimized distributions of suture stiffnesses and of the spacing of suture anchors can balance the forces across sutures to within a few percent, even when accounting for tendon viscoelasticity. Non-optimized distributions resulted in concentrated force, typically in the outermost sutures. The mathematical framework provides a foundation for optimizing suturing strategies, and results underscore the importance of accounting for viscoelastic effects in the design of tendon to bone repairs.
Guy Genin, Shaun Sellers, Victor Birman