Chapters authored
Treatment of Non-Union and Bone Loss of Tibial Pilon
Non-union is a fracture with no healing potential without a further surgical procedure. Diagnosis of non-union can be done in case of healing failure from 6 to 9 months after the first fracture. We consider appropriate to keep the attention of the reader on the relevance that more frequent traumatic mechanisms have in relationship with evolution and eventual failure of healing processes. In literature, non-union mean rate for tibial pilon fractures is around 5% independently from the synthesis technique used; as main causes we can recognize a significant fracture’s comminution ad eventual bone loss, vascular damage, and local infection. Risk factors can be divided into two big groups: factors proper of the patient at the moment of injury (age, diseases, drugs, smoke, etc.) and characteristics of the trauma itself (comminution and dislocation of fragments, involvement of soft tissues, topography, distance between fragments). 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 surrounding tissues. 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 the evolution toward a bad bone healing process. Bone healing was, in the last 50 years, argument of intense research activity. The incidence of non-union is growing steadily, although principles and materials of synthesys are well standardized. Recently it has been codified the “diamond concept,” which clarified different appliances mechanical and biological, these distinguished between cells, scaffolds, and growth factors. Under the mechanical profile, it must be restored the spectrum of stability that consider the set of bone and synthesis implanted. The spectrum of stability interprets Wolf’s law providing indications on the need to modulate the rigidity of the synthesis in reason of the level of instability of the pseudoarthrosis itself. During the years several kinds of non-union classifications have been proposed. The most widespread until now is the one proposed by Weber–Cech in 1976, which distinguishes vital forms (hypertrophic and oligotrophic) from non-vital forms (atrophic). In 2007 a new score classification system has been processed, which is the “Non-Union Scoring System (NUSS),” which divides patients in four big groups by score awarded based on the real non-healing risk. 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. Biotechnologies at our disposal are synthetic growth factors, the autologous growth factors and platelet-rich plasma, mesenchymal stem cells, and scaffolds or bone substitute. The biologic chamber represent the ideal site for bone regeneration; it is a bio-reactor in which are present all those elements at the base of the concept of diamond. The chamber needs to be aseptic, vital, mechanically stable, and sealed but selectively permeable. Thanks to the use of megaprosthesis not only in oncologic orthopaedics, but also it is now possible to avoid the amputation or long and often inconclusive treatment of lengthening or ankle arthrodesis. The new frontier in treatment of non-unions will be genetic therapy, that is, the possibility to transport to the patient those genes that con drive to the formation of good bone callus and his maturation toward strong bone.
Part of the book: Advanced Techniques in Bone Regeneration