ISBN 978-3-8439-2309-5

978-3-8439-2309-5, Reihe Biomechanik

Sven W. Herrmann
Dynamic Testing of Total Hip and Knee Replacements under Physiological Conditions

134 Seiten, Dissertation Universität Rostock (2015), Softcover, A5

Zusammenfassung / Abstract

Despite standardized surgical procedures, failure constitutes a substantial problem after total joint arthroplasty. Besides infection, loosening and fracture, postoperative instability prevails as a major complication in daily clinical practice. Both its obscurity and the severe consequences for patients, especially in case of dislocation, make it difficult for clinicians to find appropriate countermeasures. In this context, there is little evidence in how exactly soft tissue structures contribute to stability of total hip (THRs) and knee replacements (TKRs). The same applies to dynamic effects of certain parameters such as implant design and positioning. Therefore, biomechanical investigations seem invaluable which at best meet with the demands of in vivo analyses, even for instability-associated maneuvers.

As measurements in patients are afflicted with ethical objections, the purpose of this work is to present a comprehensive approach capable of testing total joint stability under dynamic, reproducible and physiological conditions. The approach is based on a hardware-in-the-loop (HiL) simulation where the anatomic and physiological environment of the implant is extracted into a simulation model described by a multibody systems formulation. Interaction between the model and the real implant components is achieved by a physical setup composed of an industrial robot equipped with a force-torque sensor and a compliant support with displacement sensors attached to. An essential aspect of this work represents the validation of the HiL test system as regards THR and TKR testing. This includes developing specific multibody models of the musculoskeletal system which reproduce physiological test conditions within the HiL environment. In this sense, the HiL test system extends the repertoire of approaches and methods commonly used in orthopedic research by combining the advantages of real implant testing and model-based simulation.