[Pseudarthroses].

Fractures and osteotomies are characterized by a structural discontinuity of the affected bone with formation of a gap. If bone healing does not lead to an osseous bridging of the fragments within a time period of 6 months a nonunion (pseudarthrosis) occurs. In this stage spontaneous bone healing is unlikely in the future without any intervention. Pseudarthrosis is classified into hypertrophic and atrophic types. Moreover, the differentiation between aseptic and septic conditions, the size of the defect, the local blood supply and the mechanical stability are crucial for treatment planning. The type of pseudarthrosis and the accompanying comorbidities can be classified in scoring systems and influence the selection of the treatment procedure. The operative principles aim at the vitalization of atrophic bone parts, achieving sufficient stabilization and cures the infection, whereas nonoperative measures are primarily supportive measures. The foundation of successful treatment is the minimization of individual risk profiles and sufficient patient compliance.