Affiliations: [a] ICIST, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal | [b] Department of Civil Engineering, Architecture and Geo-resources, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal | [c] Hospital da Luz, Avenida Lusíada 100, 1500-650 Lisboa, Portugal | [d] Clínica Universitária de Ortopedia, Medical School, University of Lisbon, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
Correspondence:
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Corresponding author: Fernando Simões, ICIST, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal. Tel.: +351 218418409; Fax: +351 218497650; E-mail: [email protected].
Abstract: In this study, three-dimensional finite element models based on the specific anatomy of a patient presenting a femoroacetabular impingement of the “cam” type were developed. The finite element meshes were obtained from arthrographic magnetic resonance images captured before and after hip arthroscopy. All soft tissues were considered linear elastic and isotropic and the bones were assumed as rigid. Physiological loads and rotational motions were applied. Stresses and contact pressures were evaluated in these patient specific models in order to better interpret the mechanism of aggression of the cartilages and of the labrum and to evaluate the effectiveness of the surgery. The results of the analyses are presented and discussed. The values obtained for the stresses and contact pressures in the pathological hip were similar to those reported by other models based on idealised geometries or similar reconstruction methodologies and were larger than the ones obtained in the same hip after the surgical treatment. The surgical treatment effectively reduces the intra-articular pressures and stresses approaching the values of a normal hip. Thus, early surgical treatment may help to prevent, or delay, the joint degeneration.
Keywords: Hip joint, femoroacetabular impingement, osteoarthritis, finite element method, geometric modelling
