Failures in bone healing can result from technical problems, biologic failures, or a combination of the two. Inadequate stabilization of bone fragments against the effects of rotational forces is a common cause of nonunion. Early identification of a pseudoarthrosis can be difficult; the diagnosis is usually delayed, thus the morbidity associated with this disorder is significant. Often, the nonunion is complicated by atrophy of surrounding soft tissues, muscle contracture, and stiff joints. The goals in the treatment of the nonunion are to identify and correct the underlying causes, with the primary objective being the return of function. The type of treatment depends on the classification of the pseudarthrosis, including the condition of the surrounding soft tissues, blood supply, and viability of the nonunion, location, and presence or absence of infection.