Osteomyelitis is one of the most severe complications that can arise following operative treatment of bone. It requires a long-term treatment. The patient can never be sure that it heals completely. The pathophysiology depends on: (1) the extent of soft tissue damage and impairment of blood supply; (2) inoculation of bacterial flora; (3) the instability of the fracture area; and (4) the general defensive condition of the organism. The symptoms of acute osteomyelitis are those of acute inflammation. They appear 1 week to 3 months after operation. The diagnosis can only be made on clinical examination by an experienced surgeon. X-Ray findings are lacking. The treatment of acute osteomyelitis involves debridement of soft tissue and bone sequesters, refixation of the fragments, most often by means of an external fixator, and suction drainage or wet dressing. The reconstruction of the bone is done in a second step. The cancellous bone grafting is performed from a medial approach. Closure of the soft tissue follows. In the case of chronic osteomyelitis scarring, fistulas and muddy secretion are present. The function of the bone is disturbed. X-Ray examination shows loosening of the metal and failing structure of the bone. In this case too, the first step is the debridement of soft tissue and bone. All the metal inside is removed. Stabilization is achieved by means of an external fixator. Once the fracture area has been cleaned, cancellous bone grafting is done once, twice, or even more frequently. For wound closure it is necessary to rotate muscle groups, to cover the bone with dermatomic skin, or to use microvascular flaps.(ABSTRACT TRUNCATED AT 250 WORDS)