Detaillierte Beitrags-Information
| Beitragstitel | Joint compression forces in abnormal version of acetabulum or femur in different joint positions- a 3D finite element study |
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| Beitragscode | P039 |
| Autoren | |
| Präsentationsform | Poster |
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| Abstract |
INTRODUCTION Impingement surgery aims to restore impingement-free range of motion (ROM). The role of the femoral torsion in femoroacetabular impingement is gaining on interest, but has not yet been fully understood. In this study we focus on the ROM and cartilage load in a finite element model with a compensatory condition of acetabular retroversion and increased femoral antetorsion. METHODS MRI scans of a healthy subject were used to obtain two different finite element models simulating load scenarios during stance phase: 1. a healthy model (HM) and 2. a model with combined acetabular retroversion (-10°) and increased femoral anteversion (+20°) (AR-FAM). Motion data and joint reaction forces (JRF) measured in our gait lab were integrated. Localization and magnitude of hip JRF were determined, as well as ROM and forces of the hip abductors for both constellations. RESULTS ROM of hip flexion was 113° and 114°, whereas internal rotation was 32° and 46° for the HM and AR-FAM, respectively. Muscle moment arms were shortened from an average of 3.5cm to 2.9cm (17.0%) with increase to 20° femoral antetorsion. Average muscle forces of the hip abductors were increased from 146 N (HM) to 172 N (AR-FAM, 18.2%), and the resultant JRF was raised from 317 to 395 %body weight (24.6%). Average pressure was increased by 25.6% between HM and AR-FAM (1.1 to 1.3 MPa). Localization of the pressure was not markedly changed in the two models. CONCLUSION In a morphological condition when increased femoral antetorsion compensates for acetabular retroversion achieving a physiological ROM, the joint reaction forces during normal gait show substantial alteration in this FE model. Individualized impingent surgery should not only normalizes impingement free ROM, but also needs to optimizes joint load. |