TS7: BIOMECHANICS OF FRACTURE HEALING – DO WE KNOW HOW TO TREAT SIMPLE FRACTURES?

Abstract

Successful treatment of bone fractures requires a balance between stability, to restore functional anatomy and allow early mobilisation (and thus avoid dystrophy). The healing occurs through complex interactions of inducing, enabling and inhibitory factors. The mechanical environment (e.g. stress and strain) in/around the fracture site regulates tissue changes throughout the healing process, including the formation of a fibro-cartilaginous callus and its progressive replacement by bone. The mechanical and biological environment is controlled substantially by the selection of the fracture stabilisation method achieving either absolute stability (mostly achieved with compression plating technique) or relative stability allowing a limited amount of dynamic fracture displacement across the fracture gap. A number of treatments may be used to accomplish these conditions, ranging from splinting with a plaster cast, external fixator or an intramedullary nail to rigid internal fixation using plates affixed to the bone fragments. Fixation methods are presently selected on the basis of general guidelines, but nevertheless the optimal stability/instability remains unclear and relies heavily on the surgeon’s experience. With the recently more and more widely used locking plates the question of the optimal fixation technique and applied stability to the fracture zone especially in simple fractures have raised again.

To fill this knowledge gap, an interdisciplinary approach with in vitro and in vivo experiments seems to be essential. Analysing clinical situations and the healing course with mathematical modelling and computational simulations can further aid to understand the healing conditions in respect to stability.

This presentation will give an overview on the role of the mechanical environment in fracture healing, and demonstrating clinical examples that highlight the relevance of this research.