An orthopedic screw is used in a fixation device for treating fractures. The device has a body with holes to accept the bone screws. The bone screws have a layer of bioresorbable material on the shaft. Engagement between the bone screws and the body is initially through the bioresorbable material, which engagement rigidly fixes the relative angular orientation between the bone screws and the body when the device is applied to a bone. As the bioresrobable material is resorbed the angular relation between the bone screws and the body is no longer rigidly fixed, thereby effecting a transformation from rigid osteosynthesis to flexible osteosynthesis to allow micromotion between the bone fragments which promotes healing.
