Calcaneus stress fractures: A finite element analysis

Shock absorption strategies targeted at reducing ground reaction forces during impact have been unsuccessful in decreasing stress fracture development in the calcaneus. We hypothesize that the critical loads on the calcaneus are instead due to muscles forces. We performed a finite element analysis to estimate the time-evolution of stresses in the calcaneus during single support phase of a self-paced walk. Local stresses were found to be higher than the yield stress and located at the interface between the calcaneus and the Achilles´ tendon. This supports the hypothesis that stress fractures are likely to be the effect of muscles forces rather than the impact of the foot to the ground.