Adhesive-based tendon-to-bone repair: failure modelling and materials selection

Abstract

Surgical reattachment of tendon to bone is a procedure marked by high failure rates. For example, nearly all rotator cuff repairs performed on elderly patients with massive tears ultimately result in recurrence of tearing. These high failure rates have been attributed to stress concentrations that arise due to the mechanical mismatch between tendon and bone. Although recent studies have identified potential adhesives with mechanical properties tuned to alleviate these stress concentrations, and thereby delay the onset of failure, resistance to the progression of failure has not been studied. Here, we refined the space of adhesive material properties that can improve surgical attachment by considering the fracture process. Using cohesive zone modelling and physiologically relevant values of mode I and mode II adhesive fracture toughnesses, we predicted the maximum displacement and strength at failure of idealized, adhesively bonded tendon-to-bone repairs. Repair failure occurred due to excessive relative displacement of the tendon and bone tissues for strong and compliant adhesives. The failure mechanism shifted to rupture of the entire repair for stiffer adhesives below a critical shear strength. Results identified a narrow range of materials on an Ashby chart that are suitable for adhesive repair of tendon to bone, including a range of elastomers and porous solids.

Effects of tendon viscoelasticity in the distribution of forces over sutures in a model tendon-to-bone repair

“…The response of the repair idealized as explained here was considered, concentrating on the relative stiffness and positioning of three suture rows to achieve a desirable force distribution. Even better results may be possible by combining sutures with an adhesive layer bonding tendon to bone ( [11,24]). Similar ideas of combined bolted-bonded attachments have been considered in repairs of aerospace structures (e.g., [25]) and proven effective.…”

Joining soft tissues to bone: Insights from modeling and simulations

“…Clearly, it is highly challenging to bridge such a gap between the organ scale (relevant to address applied orthopedic questions) and the (sub-)micrometer level (suited to investigate basic anchoring strategies). To some extent, computational multiscale models could be helpful and may, for example, trigger the development of novel (biomimetic) adhesive ( Avgoulas et al, 2019 ), recapitulating for certain aspects the material behavior of healthy entheses.…”

Boost Tendon/Ligament Repair With Biomimetic and Smart Cellular Constructs

“…Adhesive can be used as an adjuvant for surgical treatment of tendon/ligament injuries, with attention to anisotropy and the direction of force applied. The toughness of the adhesive will also have a large impact on the treatment efficacy ( Avgoulas et al, 2019 ). Nanocrystalline domains composed of PVA hydrogels were anchored to solid substrates through annealing treatment, endowing fatigue-resistant adhesion to engineering materials including glass, stainless steel and ceramics.…”