Implant Biomechanics
An orthopaedic registrar is planning internal fixation of a distal radius fracture in an elderly osteoporotic patient. She is considering screw selection to optimize fixation strength. During the pre-operative planning session, the consultant asks about the factors affecting screw pullout strength and the differences between cortical and cancellous screw design. Regarding screw biomechanics and pullout strength:
Mark each as TRUE or FALSE
Screw pullout strength is determined primarily by the shear strength of bone at the thread-bone inte...
Thread pitch is the distance between adjacent threads; a smaller pitch means more threads per unit l...
The inner (core/minor) diameter of a screw determines pullout strength; increasing core diameter whi...
Cancellous screws have larger outer diameter relative to core diameter (deeper threads), coarser pit...
The outer (major) diameter is the single most important screw design factor for pullout strength as ...
Answer the questions to see explanations
Click T (True) or F (False) for each option