In vivo subtalar joint contact forces during eversion to inversion motion

Background: The subtalar joint describes an articulation between the talus and calcaneus. The bones are connected by a complex and strongly binding ligamentous structures that helps preventing distraction/separation of the talus from the calcaneus during weightbearing activities. In general, subtalar joint motion can be broken down into a rotation about, and a translation along a single axis of rotation passing through the middle facet and constrained to pivot about a centre of rotation located in the region of the middle facet. Movements of the subtalar joint accommodate irregularities in ground contact by unlocking the hind and midfoot during heel strike to stance phase. The changing talocalcaneal relationship plays a key role in stabilising the ankle complex. The importance of this can sometimes be seen when the natural condition is disrupted by subtalar fusion operations. Fusion causes transmission of abnormal forces and stresses, leading to an increased risk of wear and tear. In vivo estimation of the subtalar joint reaction forces and contact stresses can unveil unique information about the biomechanics of the joint and could help understanding the disease mechanisms involved in structural damage progression.

Project: The project aims at developing a subject-specific image-based computational model that allows to investigate the biomechanics of the subtalar joint during eversion to inversion motion in healthy subjects. Key tasks of the projects are:

  1. Generation of subject-specific finite-element models based on weightbearing computed tomography (WBCT) data of the subtalar joint.
  2. Validation of these models against existing experimental 3D displacement measurements derived from digital volume correlation (DVC) analysis.
  3. Estimation of the joint reaction forces and contact stresses at the subtalar joint involved in eversion to inversion motion.

Impact: At present, subtalar joint fusion is the only operative treatment for end-stage hindfoot arthritis, which is estimated to affect up to 70,000 people in the UK alone. Although subtalar joint replacement has been attempted, is has not been successful, with early failure rates above 50% within the first year. This project represents a unique opportunity to predict the contact mechanics in the joint. This will ultimately serve to design a subtalar joint replacement that emulates the function of the subtalar joint in a reliable and realistic manner.

Supervisor name: 
Uwe Wolfram
Supervisor and Deputy email addresses: 
u.wolfram@hw.ac.uk, M.Pena_Fernandez@hw.ac.uk
Deputy name: 
Marta Peña Fernández