An introduction to selected chapters in bone biomechanics.

In the introduction to this Injury supplement, an attempt is made to elaborate on important rules of biomechanical research such as were developed and used in the Davos school of biomechanics. Tribute is acknowledged to the important contributions of S.M. Perren, M. Russenberger and S.G. Steinemann. The following principles are illustrated: 1. The development of a new technique or a new implant is justified when it is the solution of a clinical problem or a clinical complication. 2. The appropriate solution in engineering is often simple and elegant. 3. The first step of a biomechanical investigation concerning fracture treatment consists in establishing to which patients this study will apply. 4. For a testing instrument, freedom is important at the junction between the bone and the loading device. 5. A selection of bones should be made prior to the experiment in regard to the clinical population involved. 6. In our biomechanical investigations, we are not interested in a "statistically significant" difference, but in a "clinically significant" difference. The communications presented in this supplement of Injury are a tribute to the 30 "Perren'sche Jahre" (Perrenic Years) of what I call the School of Biomechanics in Davos.