(iii) Principles of internal fixation

Abstract

The continually evolving understanding of bone biology has led to a new approach to internal fixation. In comminuted diaphyseal and metaphyseal fractures, anatomical reduction is no longer a goal in itself. Preservation of the viability of the bone fragments is the key to unimpaired fracture healing in internal fixation. The rapid integration of vital fragments into the fracture callus buttresses the fracture area and prevents fatigue failure of the implant. Important factors are length, axial and torsional alignment. Additional bone grafting is rarely necessary. Indirect reduction technique followed by balanced fixation is a concept to achieve undisturbed fracture repair in the metaphysis and diaphysis. In articular fractures precise alignment is required. Any incongruency will be followed by local overload and subsequent degenerative changes in the articular cartilage. The combination of indirect reduction technique (ligamentotaxis) and accurate direct reduction — of certain strategic fragments — helps to minimize devitalization. To help to accomplish this new concept of biological internal fixation, new implants such as the unreamed solid medullary nail and limited contact plates (like the LC-DCP), which minimize additional vascular damage, have been introduced.