A large-deformation, finite-element study of chondrodiatasis in the canine distal femoral epiphyseal plate

A large-deformation, finite-element analysis was conducted to model stress fields around the developing growth plate as a first approach to comprehend the clinical application of traction for limb lengthening procedures. The model chosen was a cross section through the distal femoral growth plate of a 14-week-old dog. The chosen section passed through two of the conformational bends (mammillary processes) formed by the natural convolutions of the physis. Three different loading conditions were applied to the distal femoral epiphyseal model. The model also examined the effects of different values of Young's modulus of the growth-plate cartilage. The cortical bone in all cases, experienced the highest stresses. In the growth plate, the highest principal stresses occurred where the physis intersects cortical bone. There were localized stresses that were higher than those that caused fracture in a rabbit model [Guse et al., J. Orthop. Res. 7, 667–673 (1989)]. Results also indicated the following: a small tilt of 0.1 in loading application increases the maximum principal stresses and the von Mises stresses in certain regions of the growth plate by about 8%; the shearing streses in the growth plate are sensitive to Young's modulus of the growth plate; and traction pins that do not grip the cancellous bone in the epiphysis will increase the regions of high principal stress in the growth plate.