Analysis of the stress and strain in hip joint of the children with adductors spasticity due to cerebral palsy.

Mechanical factors have a strong influence on the development of the musculoskeletal system. Muscle forces are one of the most important sources of the loadings acting on the bone elements and any disturbances in their activity can lead to severe pathology. Cerebral palsy is an example of such a situation and hip joint deformity, leading to its dislocation, is one of the most serious complications accompanied with muscle spasticity. The aim of the study is to perform an analysis of the stress and strain in hip joint of the children with the imbalance in muscle forces due to adductors spasticity (overactivity). Finite element model has been developed based on anatomical data obtained from computer tomography. The results of numerical simulations show an increase in stress and strain occurring in the femoral head and acetabulum as well as some relocation of its concentration zone in the medial direction.