title: An automated system for measuring multi-dimensional, time dependent mechanical properties of a human tibial fracture.
abstract: An automated loading and measurement device has been developed for assessment of the mechanical properties of a healing human tibial fracture. The characteristics of the device are presented with assessments of errors. This paper constitutes a small part of a long term research project determining a clinically quantifiable end point for fracture healing in humans, hence a sample of results is presented to demonstrate the potential application of the device. A more detailed analysis of the results will be the basis of further publications. The initial results confirm that the non-linear behaviour of callus cannot be ignored in fracture assessment methodologies. They further reinforce the requirement to measure load-rate when measuring fracture stiffness. Polar plots of stiffness demonstrate that when measuring fracture stiffness not only should load-rate be considered, but also the orientation of measurement. The results from this work support the view that fracture stiffness should be measured in at least two planes. A new material property for the assessment of fracture healing, the gamma ratio gamma, is examined and preliminary results are shown. The paper also demonstrates how creep properties of a healing tibia can be assessed and proposes that this property may form the basis for future fracture assessment investigations.
authors: Staffordshire University, Stafford, Staffordshire ST18 0AD, UK. p.j.ogrodnik@staffs.ac.uk
authors: Peter J
authors: PJ
authors: Ogrodnik
authors: C Ian
authors: CI
authors: Moorcroft
authors: Peter B M
authors: PB
authors: Thomas
mesh_terms: D001331:Automation; D001696:Biomechanical Phenomena / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D004548:Elasticity; D004867:Equipment Design; D019544:Equipment Failure Analysis; D050723:Fractures, Bone / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D015233:Models, Statistical; D010808:Physical Examination / Q000295:instrumentation* / Q000379:methods; D010812:Physical Stimulation / Q000295:instrumentation* / Q000379:methods; D013314:Stress, Mechanical; D013977:Tibia / Q000473:pathology*; D013978:Tibial Fractures / Q000175:diagnosis* / Q000503:physiopathology*; D013997:Time Factors; D014783:Viscosity; D016474:Weight-Bearing