Comparative Analysis of Healthy and Cam-Type Femoroacetabular Impingement (FAI) Human Hip Joints Using the Finite Element Method

Rubén Lostado Lorza,Marina Corral Bobadilla,Álvaro Pérez Sala,Rafael Peláez Cristóbal,Saúl Íñiguez Macedo,Fátima Somovilla Gomez,Asier Rodríguez San Miguel,Enrique Fernández Martínez,Manuel Rubio Sampedro,Ignacio M Larráyoz

doi:10.3390/app112311101

Rubén Lostado Lorza, Marina Corral Bobadilla + Show 8 more

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https://doi.org/10.3390/app112311101

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Abstract

In this study, a human hip joint with Cam-type Femoroacetabular Impingement (FAI) is studied by the Finite Element Method (FEM). This pathology consists of a malformation that causes a lack of sphericity of the head of the femur. In turn, this causes wear and tear of the cartilage, a cause of early osteoarthritis of the hip. The objective is to use the FEM to analyze and compare the increase in the von Mises stress and displacement of the cartilage in healthy and damaged (with Cam-type) human hip joints that this syndrome affects. The 3D models were reconstructed from two medical CT scans of a healthy and a damaged hip joint that were obtained, five years apart, for a male of 80 kg in weight. The 3D models were reconstructed using 3D Slicer software. The cortical and trabecular bone, as well as the cartilage, were segmented. The defects were corrected by MesMixer software that generated STL files. Both models were imported into the Marc Mentat® software for the Finite Element Analysis (FEA). It was noted that the thickness of the cartilage decreased enormously during the five years, which suggests imminent mechanical contact between the head of the femur and the acetabulum of the pelvis. The FEA results showed an excessive increase in the stress and displacement of the cartilage. This will certainly result in a condition of osteoarthritis for the patient in the future years.

Highlights

The hip joint is one of the most important joints in the human anatomy
It can be seen that the displacement and the von Mises stresses were, respectively, 0.1 mm and 2.41 MPa
The results indicate that the maximum displacement of the cartilage was 0.437 mm, whereas the maximum von Mises

Summary

Introduction

The hip joint is one of the most important joints in the human anatomy. It is the largest joint that the human beings have and is the one of greatest bone contact. The mechanical properties considered were isotropic and linear elastic for the bone and cartilage Both activities produced von Mises stresses and contact pressures in the acetabular cartilages. The anterosuperior bone surface experienced the highest stress This occurred beneath the acetabular cartilage when patients who had severe Cam FAI (15.2 ± 1.8 MPa) sat or squatted. In [12], an FE model of a Cam FAI caused von Mises stress and contact pressure in the anterosuperior cartilage (14.4 and 11.6 MPa, respectively) and labrum (14.7 and 16.4 MPa, respectively) during hip flexion. A proximal femur model was constructed from CT data that had been parameterized with three different growth plate shapes It simulated four activities, which were internal rotation, external rotation, hip flexion, and normal walking. The objective of the current study was to analyze and compare the von Mises stress and displacements of the cartilage

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