Evaluation the deformation of femural head in subjects with Leg Calve Perthes Disease

Background: The femoral head in subjects with Leg Calve Perthes Disease (LCPD) deforms significantly. It is controversial whether the deformation of femur is due to increase in applied loads, decrease in bone mineral density or change in containment of articular surfaces. Therefore the aim of this study was to determine the influence of these changes on deformation of femoral bone. Method: Two subjects with LCPD participated in this study. The motions of the subjects and the force applied on the leg were collected with use of Qualysis motion analysis system and a Kistler force plate. Open Sim software was used to determine joint contact force of hip joint while walking with and without Scottish rite orthosis. The 3d Models of hip joints of both subjects were produced by Mimics software. The deformation of femoral bone was determined by Abaqus software. Results: The mean values of the force applied on leg increased while walking with orthosis. There was no difference between BMD of femoral bone of normal and Perthes sides (p-value 0.05). There was no difference between hip joint contact force of normal and Perthes sides. The hip joint containment seems to decrease follow the use of orthosis. Conclusion: It can be concluded that the deformation of femoral head in LCPD may not be due to change in BMD and applied loads. Although Scottish rite orthosis is used mostly to increase hip joint containment, it seems to decrease hip joint contact area. It is recommended that the same study will be done on more number of subjects.