Biological internal fixation: its background, methods, requirements, potential and limits.
The surgical treatment of fractures made essential progress when stable internal fixation allowing for immediate painless mobility of soft tissues and articulations was postulated and achieved. This step required basic understanding of biomechanics of fixation and of bone reaction to compression and micromotion. The definition of teaching modalities and the clinical documentation were further steps leading to general acceptance of this type of treatment. After a period of interest, which was focussed mainly on biomechanics it became obvious that biology was not only important for reliable bone and soft tissue healing but especially important for good local resistance to infection and quick solid bridging. The surgical approach with special care to the viability of the bone as a tissue is called biological internal fixation. Similar attempts were seen in the past but it appears that now an procedures and implants have been developed that maintain undisturbed blood supply thus avoiding extended contact necrosis. The advantage of biological internal fixation consists in reducing severe biological complications on the expense of less important mechanical shortcomings. Biological internal fixation is best, when the bone is alive at the onset of surgery and remains so. The present paper focussing especially on the development of implant technology for flexible biological internal fixation should not distract from the needs of necrotic bone for long-term stable compression fixation achieved by conventional techniques. Key words: biological internal fixation, osteosynthesis.
Perren
S M
SM
AO Research Institute, Davos Platz, Switzerland.