**5. Non-union classification**

anatomic reduction of fragments with the intent to preserve vascularization is a positive

Tibial pilon fractures are mainly caused by high-energy trauma. This kind of dynamic determines not only more serious damage to the bone, but often cause damage of the sur‐

Following important lesions of the periosteum and of the vascular network and after a suboptimal synthesis caused by comminution and dislocation of fragments is frequent with

After the end of the 1980s, thanks to statistic analysis proposed by authors as McFerran [3] and Dillin [12] and, more recently Piper et al. [13], it was possible to clarify the importance of risk

Distal tibia is characterized by a relatively poor vascularization and skin coverage. These structures, when seriously damaged from the mechanism of injury, penalize the healing of

There are several factors to whom was charged complicity in the development of such an

Its, however, not negligible the eventuality that fractures of patients treated correctly, and with

It seems that the population of patients affected by non-union is somehow selected toward those patients that present a higher risk of this complication. For this reason, it seems even more important to analyze and classify these patients to define better surgical program and

Is not a rare observation that some subject, unfortunately few in number, even if treated not correctly shows "miraculous healing." Instead, is greater the number of patients that, although

Bone healing was, in the last 50 years, argument of intense research activity. The number of non-union is constantly growing although principles and material of synthesis are standar‐

prognostic factor.

110 Advanced Techniques in Bone Regeneration

the evolution toward a bad bone healing process.

eventuality; among the most important, we find:

low-risk rate, could evolve toward non-union.

even in some way to clarify the risk of treatment failure.

**•** A loss of skin coverage after injury;

**4. Bone healing**

**•** A residual bone loss after the reduction of the fracture;

**•** The precariousness of the metaphyseal vascularization;

**•** An inadequate mounting in case of external fixation synthesis;

**•** A wide deperiostization during synthesis with plate and screws.

treated in a good way, under go several in effective surgical procedures.

factors that affect the prognosis of tibial pilon fractures.

rounding tissues.

fractures.

To be able to encode treatment's guidelines, we must first proceed to a correct nosological assessment of the problem. During the years, it has been proposed several kinds of non-union classifications.

The most widespread until now is the one proposed by Weber–Cech in 1976, which distin‐ guishes vital forms, hypertrophic, and oligotrophic, or rather with possible biologic response, from non-vital forms or rather non-reactive atrophic kind, frequently accompanied by osteonecrosis, and even by bone loss [16].

This classification is based on a descriptive radiological analysis of the kind of non-union evaluating only the bone, we think that a more complete classification, even from a prognostic point of view, should take into account even the quality of soft tissues and the general conditions of the patient (comorbidity, lifestyle, drugs, genetic diseases).

For this reason in 2007 have been identified through the study of international literature all possible risk factors in the healing of fractures [8].

After has been processed a score classification system, the "Non-Union Scoring System (NUSS)" [17] with double finality: not to detect a "radiographic case" but a "patient" and then detect, in relationship with the real non-healing risk, those cases in which is necessary, not only a correct surgical treatment, but even a right biotechnological approach. The NUSS represents an innovative approach to the problem because it understand the multifactorial reasons of failure, explains why in a variable percentage of cases (depending from de district affected) the healing is not obtained, even with a correct treatment and above all make possible the drafting of a therapeutic choice algorithm [18, 19].
