This book is a collection of papers, based on the communications held at the 10th Conference of the European Society of Biomechanics, which took place at Leuven, Belgium, 28-31 August, 1996. The presentations were held at three symposia: “Validation of Computer Simulations of Bone Adaptation”, “Bone Architecture and the Competence of Bone” and “Ultrasound Research in Bone”.

All presentations in this book focus on the structure of bone, and the consequences for its mechanical behaviour. This field of research has a long history, dating back to the work of Wolff, and can be described by the question: “Why does bone possess the shape and structure it actually has?”. Such a question is far from purely academic, but can have important consequences in the fields of orthopedics and metabolic bone disease research.

The papers of the first symposium can be considered as the computer-age translation of issues raised by Wolff himself. They focus on the development of models predicting the adaptation of bone due to changes in the mechanical loading situation (such as those provoked by an implant). But, far more important than the computer power presently available, the incorporation of knowledge of biological processes has led to a new kind of models. Next to the development of models itself, the issue of model validation through comparison with clinical data is a main issue addressed in the papers of this symposium.

The papers of the second symposium, dealing with the relationship between bone architecture and competence of bone, focus on the morphology of trabecular bone structure. This work is mainly carried out in the context of research on osteoporosis, and looks for the relationship between bone structure and fracture risk. The progress made during the past years in high resolution imaging techniques opens new and fascinating perspectives for the assessment of bone structure. These three-dimensional representations of bone structure also call for new assessment methodologies. Whereas nowadays conventional morphometric techniques are adopted in most cases, it is likely that these new imaging techniques will intensify the search for new and better descriptors of bone structure.

The papers of the third symposium are devoted to ultrasound research in bone biomechanics. Ultrasound measurements are gaining clinical interest, since it is expected that they reflect to a certain extent the structural bone properties. Several methods have been described for the in vitro and in vivo measurement of ultrasound velocity and attenuation, both on cortical and on trabecular bone. As such, they could offer an alternative to the high resolution radiographic techniques, which are not yet fully applicable in vivo. However, next to their in vivo use, ultrasonic techniques are available at the microscopic level too, revealing information on the elastic properties at the bone tissue level.

When reading this book, the reader will not only discover the state-of-the-art of research of bone structure, but it is also our belief that in some respects a new direction has been taken. Firstly, there is an intensified research into the biological processes involved in the bone adaptation mechanism, and its results are now being implemented in a new generation of adaptation models. Secondly, with regard to structural assessment, it can be expected that the three-dimensional investigation of bone structure will lead to new insights in the mechanical integrity of bone. Therefore, we hope that this book will also give a taste of the fascinating perspectives which the research in bone biomechanics still has to offer, even after more than 100 years.

G. Lowet, P. Rüegsegger, H. Weinans and A. Meunier

Editors