Biomechanical analysis of the correlation between mid-shaft atypical femoral fracture (AFF) and axial varus deformation.

Background: Atypical femoral fractures (AFF) are diaphyseal fractures of the elderly that occur at the end of a minor trauma. The objective of this biomechanical study, using finite element modelling, was to evaluate the variations of the femoral diaphysis fracture indicator according to the variations of the mechanical axis of the lower limb, which can explain all the different atypical fracture types identified in the literature.

Methods: In order to measure variations in stress and risk factors for fracture of the femoral diaphysis, the distal end of the femur was constrained in all degrees of freedom.

Quiet postural control of patients with total hip arthroplasty following joint arthritis.

To assess the postural strategies developed by patients after total hip arthroplasty (THA), 14 patients were measured 12 days after surgery. The respective role played by both sound and prosthetic legs and the compensatory mechanisms were assessed through a separate measure of the center-of-pressure (CP) trajectories under each foot. The movements of the center-of-gravity (CG) were estimated from those of the resultant CP to determine postural performance.