Multiscale finite element modelling to assess sutured tendon repairs

Following hand tendon lacerations, surgery is required to reapproximate the tendon ends, followed by 8 to 12 weeks of dedicated physiotherapy. Functional outcomes are less than optimal with around 25 % of patients suffering from residual disability. Despite numerous in vivo and ex vivo studies there is no unified approach to suture repair of the tendons whereby design is arbitrary. We have developed a 3D multi-scale Finite Element (FE) model to assess the different tendon suture repair techniques. The FE model shows detailed stress and strain within the tissue, which is not possible by existing methods of analysis, and is also rapid and cost effective. Whilst tendon has been modelled in the past, our work is tailored to suture repair analysis as it accounts for the tissue’s microstructure. High stress regions within the Kessler suture correlate with known acelullar regions observed in a murine (mouse) tendon injury model. Acelullarity is detrimental to tendon mechanical properties due to lack of tissue maintenance by the fibroblasts (tendon cells). Calculating high stress regions in suture repairs will show which techniques provide the most favourable environment for healing and long term tissue health.