The effects of function and fixation stiffness on experimental bone healing.

In tibial shaft fractures in the rabbit, the early stage of bone healing after metal-plate fixation was compared with that after treatment with a long or short plaster cast. The animals were killed after 6 weeks. The plate-fixed bones healed more rapidly, with less periosteal callus and less angulation of the fragments, than those treated with a cast. The results indicated that function of the muscles and joints of the injured limb, including weight bearing, promotes bony union, whereas the degree of fixation stiffness is relatively unimportant.