The assessment of contact stress in the hip joint after operative treatment for severe slipped capital femoral epiphysis

Abstract

We determined contact stress on the articular surface of the hip joint in a group of patients who underwent operative treatment for severe slipped capital femoral epiphysis. Two different procedures were considered: the modified osteotomy of Dunn-Fish and the osteotomy of Imhäuser. In order to determine the stress distribution, a three-dimensional mathematical model was used taking into account the geometrical parameters of the pelvis and hip, which were measured from standard antero-posterior radiographs. We found that the Dunn-Fish procedure produced lower peak stress than the Imhäuser procedure.Résumé Nous avons determiné la pression sur la surface articulaire de la hanche dans un groupe de patients operés pour épiphysiolyse femorale supérieure. Deux opérations ont été considereés: l'opération de Dunn-Fish modifieé et l'ostéotomie d'Imhäuser. Pour déterminer la distribution des pressions, un modèle mathématique tridimensionel a été employé, tenant compte des paramétres géometriques du bassin et de la hanche, obtenus à partir des clichés antéro-postérieurs. Nous avons trouvé que dans les hanches opérées par la procedure de DunnFish modifiée les pics de pression sont inférieurs à ceux dans les hanches opérées par la technique d'Imhäuser.

Computer Determination of Contact Stress Distribution and Size of Weight Bearing Area in the Human Hip Joint

“…The calculated hip joint resultant force R should be scaled by the individual variations in femoral and pelvic geometry [6,17,18]. For this reason, the reference values of the model muscle attachment points [10] and the interhip distance l are rescaled in order to adjust the configuration of the hip and pelvis for the individual person.…”

“…2): the interhip distance (l), the pelvic height (H ), the pelvic width (C ), the vertical and the horizontal distance from the center of the femoral head to the effective muscle attachment point (T ) on the greater trochanter (z and x, respectively). The point T is determined by the intersection of the contour of the greater trochanter and the normal through the midpoint of the straight line connecting the most lateral point (point 1) and the highest point (point 2) on the greater trochanter [17,18]. The above-described geometrical parameters are used to scale the respective reference values of the attachment points of the muscles included in the model (Table I) and the interhip distance for an individual person.…”

Mathematical estimation of stress distribution in normal and dysplastic human hips

“…A computer program (HIJOMO) [7,32,35] was then used to measure the radiographic parameters ( Subsequently a computer program (HIPSTRESS) [15-18,31,34] was used to compute the magnitude and direction of the resultant hip joint force R and the corresponding stress distribution in static onelegged stance. In calculating R, the 3D reference coordinates of the muscle attachment points were taken from the work of Dostal and Andrews [S], who performed a case study on one human pelvis and measured 3D coordinates of the abductor muscles.…”

Acetabular Augmentation by Residual Hip Dysplasia

“…The individual variations in the femoral and pelvic geometry influence the directions of the muscle forces as well as the radius vectors of the application points of the muscle forces on the pelvis and femur. Therefore the geometry of the hip should be adapted for each patient individually according to the data determined from standard anteroposterior radiographs Iglič et al, 2001Zupanc et al, 2001). The input geometrical parameters of the model for determination of R are shown in the Fig.…”