A biomechanical study of lateral ankle sprain

Lateral ankle sprain is amongst the most common musculoskeletal injuries posing a significant economic and resource burden on healthcare systems. The high prevalence of chronic residual symptoms following ankle sprain can severely impact patient quality of life and contribute to the development of post-traumatic osteoarthritis. The research presented hereinafter aimed to advance the development of synthetic interventions for ankle sprain by mechanically characterising the lateral ankle ligaments, analysing changes in joint stability following simulated sprain and evaluating the effectiveness of synthetic interventions to restore joint stability. Strain rate was identified to significantly influence the failure load of ligaments demonstrating the importance of mechanically characterising ligaments at appropriate rates of loading. Characterising the lateral ankle ligaments determined that the ultimate failure load and stiffness of the lateral ankle ligaments do not differ systematically, however a tendency toward greater strength in people with a higher body mass index was identified. A sectioning study of the lateral ankle ligaments analysed joint stability changes using anterior drawer and talar tilt tests determining lateral ankle stability to decrease with increasing damage. When repaired successfully synthetic intervention was able to adequately restore joint stability however catastrophic failure of suture tape fixation was frequent, particularly during inversion motion. Suture anchor fixation of synthetic interventions was mechanically characterised in both porcine bone and a Sawbone model. Sawbone, used routinely for manufacturer testing, was determined to be an inadequate model of human bone. Loads achieved by the suture anchor fixation for the InternalBrace (Arthrex Inc, Naples, FL, USA) were below that of native lateral ankle ligaments but could be doubled by a simple adaptation proposed to prevent suture tape slippage. This thesis advances the development of suture tapes and their fixation for the treatment of lateral ankle sprain however further research is required to seek benefit in their use.