The Challenge of Plate-Bone Construct Stiffness: A Swinging Pendulum: Commentary on an article by Michael Bottlang, PhD, et al.: "Dynamic Stabilization with Active Locking Plates Delivers Faster, Stronger, and More Symmetric Fracture-Healing".

Abstract

Fracture plating has evolved in parallel with better understanding of the biology and mechanics of bone healing. Although treatment of the simple plane fracture with compression plating and absolute stability has been successful in most instances, clinicians still largely rely on experience and judgment to decide how to best treat comminuted fractures and fractures in osteoporotic bone where compression is not an option. Stephan M. Perren’s strain theory1 and studies that followed have taught us that, for bone to heal, there needs to be an ideal amount of micromotion at the fracture site. Too much, and the callus never consolidates; too little, and no bone is formed. Locking fixation seemed to be an excellent solution to the problem of poor fixation in osteoporotic bone; however, with its use in some instances, we created a new problem of constructs with such stiffness that osteocytes at the fracture are not signaled to form callus1,2. One solution to this new problem has been far cortical locking, where the near cortex is effectively overdrilled to allow for increased micromotion while still using locking screws to maintain the benefits of fixed angle stability. This technique arose from the observation that healing callus in locked constructs is often seen …