Finite element analysis on contact mechanics of cartilage in hips with Cam-type femoroacetabular impingement / 医用生物力学

ABSTRACT

Objective To compare contact mechanics of cartilage in normal hip and that in hip with Cam-type femoroacetabular impingement (FAI) using finite element method. Methods The 3D finite element models of normal hip and Cam-type FAI hip joints with varied Alpha angles were constructed. The contact pressures and stresses of intra-articular cartilages during routine daily activities, such as walking, sitting and standing, were calculated. Results During the whole gait cycle, the distribution of cartilage contact pressures on Cam-type FAI hip models with varied Alpha angles was similar to that in normal hip model, and no concentrated areas of high contact pressures and Von Mises stresses appeared. While during the motion of sitting and standing, the cartilage contact pressure on Cam-type FAI hip models was higher than that in normal hip model and increased with the Alpha angle increasing, and the contact area was mainly located at anterosuperior region of acetabular rim, where a concentration of high contact pressures and Von Mises stresses appeared. Conclusions Mode of motion is the key factor which causes changes of cartilage contact mechanics in Cam type FAI joints. Abnormally high cartilage contact pressures and Von Mises stresses might be the inducement to cartilage degeneration and eventually lead to osteoarthritis.