[Fracture movement and fracture healing in plaster case fixation (author's transl)].

The fixation of a fracture in a plaster cast, or in traction is not absolutely rigid. Experiments were carried out on adaver tibial fractures placed in long leg plaster casts. It was observed that the possible deformity ranged between 4-8 degrees in a well-padded cast and 2-5 degrees in a nonpadded cast. Further observation were conducted while hip osteotomies were compressed by external fixator. These osteotomies are further protected by hip spicas. It was demonstrated that increasing the length of the cast did not increase the degree of fixation. It is suggested that fracture healing in conservatively treated cases is optimal if movement of the fragments remains within the physiological elastic limits of the not fractured bone. Fracture healing can be disturbed not only by extensively denudation and soft tissue disturbance, but also by under-or overstressing the bone and by unphysiological immobilisation.