Biomechanical evaluation of three new implants for the first metatarsophalangeal joint of the human foot

Resumen

Hallux valgus and hallux rigidus are the two most common pathologies in the fi rst ray of the foot. The treatments against these pathologies have had considerable advances in recent years. The destructive surgical techniques include arthrodesis, arthroplasty, and cheilectomy, while the nondestructive surgical techniques include many kinds of osteotomies. Arthroplasty of the first metatarsophalangeal joint is a procedure that preserves the dorsiflexion of the joint, in addition to relieving pain caused by the aforementioned pathologies. On the other hand, performing a structural analysis of the foot using analytical methods is extremely difficult, so numerical methods are a good tool to understand the biomechanics of the foot, particularly fi nite element analysis. The objective of this research is to develop a biomechanical evaluation of the foot after having developed the different types of arthroplasty in the fi rst metatarsophalangeal joint. Five fi nite element models are compared and three different implants are investigated. The results in the fi nite element models show consequences in the biomechanics of the foot after the different arthroplasty processes have been developed. For the implants investigated, a fatigue study is developed from the results of the computational simulations, based on a strain approach and making first-order Taylor series expansions, using the Ramberg-Osgood and Coffin-Basquin-Manson expressions for building a one-step B model.