Polytherapy in Bone Regeneration: Clinical Applications and Preliminary Considerations

Abstract

Polytherapy, namely the simultaneous application of three fundamental elements necessary for bone regeneration (growth factors, osteogenic cells and osteocnductive scaffolds) seems to lead to a very high success rate in the treatment of complex non-union (NU) cases and critical bone defects. NU are reported in 5–10% of long bone fractures. The use of autologous bone grafts has been long-considered the gold standard for the treatment of these cases. However the harvesting procedure from the iliac crest increases surgery time and presents some donor site complications which may be elevated. In recent years, surgeons have some alternatives to autologous grafting such as: application of organic or synthetic bone substitute, application of mesenchymal stromal cells (MSC) or growth factors (GF). In the literature there are many studies available about their application in monotherapy, but unfortunately the healing rate doesn't exceed 90%. Polytherapy seems to be a logical option to improve the healing rate, nevertheless, there are not still extensive studies that validate this strategy and moreover, some questions are not resolved.

Validation of the Non-Union Scoring System in 300 long bone non-unions

“…Resection of the non-union is usually required and consequently a bone defect must be treated. Traditional treatments may be used, such as bone transport with external fixator, autologous iliac crest grafts or microvascular fibula grafts; however, also indicated are biotechnological products, including cells, scaffold and growth factors, according to the principles of the ''biological chamber'' [31,32] and ''polytherapy'' [33][34][35][36].…”

Megaprostheses in the management of trauma of the knee

“…Numerous reconstructive strategies exist to treat large bone defects including allograft, [15][16][17] biotechnologies in mono or polytherapy, standard arthroplasty and, lastly, megaprosthesis. 2 Structural allografts have a complication rate of 23-55% [18][19][20] and include allograft resorption, non-union, spontaneous fracture and infection.…”

Non-Union Current Treatment Concept

“…In this way, the so-called diamond concept ( Figure 1) has become evermore established (3,32). Therapy consists of an optimized combination of biological and biomechanical factors (29,(33)(34)(35)(36)(37)(38) (The diamond concept has five different factors that must be analyzed for therapy) (39).…”