Is there a classification for non-unions?

Weber and Cech (1976) divided non-unions into two main types based on their x-ray appearance: hypertrophic and atrophic.

In hypertrophic cases there is over-abundant callus and the two fragments of the fracture still have the capacity for biologic reaction and thus healing.

Usually these cases of non-union need more mechanical stability. In atrophic cases, the two fragments are inert, have no biological reaction and tend towards bone resorption with subsequent necrosis (death) of the bone and loss of bone substance.

Calori (2008), NUSS (Non Union Scoring System) classification, a classification that not only evaluates the x-ray appearance of the non-union but also considers the systemic factors, the general condition of the patient, the local bone situation and the condition of the soft tissue, providing a rating of increasing severity (0-100) that can guide the surgeon in choosing the best treatment for the type of non-union and the type of patient.