Nonunion of the mandible.

Nonunion of the mandible was evaluated over a five-year period (1968-1973). Fourteen cases were noted out of 577 mandibular fractures for an incidence of 2.4 percent. Causes of the complications were determined by a careful review of the poorly healing and successfully treated cases of mandibular fracture. The most important feature in nonunion cases was the large proportion of edentulous patients. In these cases immobilization appeared difficult, especially when only one form of fixation was used to stabilize the fracture. Other suspected causes of nonunion were postoperative trauma and osteomyelitis. These factors were most prevalent in the lower socio-economic groups. Factors which did not appear important were sex, age and cause of the fracture. Analysis of the site of injury, combinations of sites, timing of treatment, periosteal stripping and general health of the patient failed to demonstrate any predisposition to the complication. Treatment of nonunion was confined to standard techniques of debridement, antibiotic therapy and further immobilization. Although most patients responded to this therapy, six patients required closure of the deficit by bone grafting. On the basis of accumulated data, it was possible to clarify the factors in the development of nonunion. It was also possible to recommend methods of prevention of the complication and to substantiate the success of several forms of therapy.