RESUMO
Approximately a third of patients presenting with long-bone non-union have undergone plate fixation as their primary procedure. In the assessment of a potential fracture non-union it is critical to understand the plating technique that the surgeon was intending to achieve at the primary procedure, i.e. whether it was direct or indirect fracture repair. The distinction between delayed union and non-union is a diagnostic dilemma especially in plated fractures, healing by primary bone repair. The distinction is important as nonunions are not necessarily part of the same spectrum as delayed unions. The etiology of a fracture non-union is usually multifactorial and the factors can be broadly categorized into mechanical factors, biological (local and systemic) factors, and infection. Infection is present in ~40% of fracture non-unions, often after open fractures or impaired wound healing, but in 5% of all non-unions infection is present without any clinical or serological suspicion. Methods to improve the sensitivity of investigation in the search of infection include the use of; sonication of implants, direct inoculation of theatre specimens into broth, and histological examination of non-union site tissue. Awareness should be given to the potential anti-osteogenic effect of bisphosphonates (in primary fracture repair) and certain classes of antibiotics. Early cases of delayed/non-union with sufficient mechanical stability and biologically active bone can be managed by stimulation of fracture healing. Late presenting non-union typically requires revision of the fixation construct and stimulation of the callus to induce fracture union.
