If a fracture enters a joint, you will not be able or equipped to reduce the fragments precisely at an open operation, or to fix them internally. If you cannot refer a patient to have this done, the alternative is active movement, as early as pain will allow. This smooths the opposing joint surfaces, and lets them mould to one another as union proceeds.
It is often said that unless the fragments of all broken joint surfaces are replaced exactly, osteoarthritis always follows. Although this is true for the ankle, it is less true for such fractures as: (1) comminuted supracondylar fractures of the humerus in adults, (2) comminuted extension fractures of the wrist in elderly patients, (3) plateau fractures of the upper tibia, and (4) comminuted fractures of the calcaneus with injury to the subtalarjoint. With these fractures surprisingly good results follow from accepting the poor position of the fragments, and allowing early active movements to smooth out the irregular joint surfaces as union proceeds. These good results are in striking contrast to the poor results that average surgeons get when they try elaborate methods of internal fixation. Experts with the AO method may get excellent results with these fractures, but many of their followers do not.