To develop an objective technique for the evaluation of electrical and mechanical stimulation methods.
In vivo assessment of bone quality by vibration and wave propagation techniques, including osteoporosis assessment and other clinical applications.
Fracture healing is traditionally assessed by a combination of manipulation (qualitative stiffness testing) and X-ray examination (qualitative image analysis). Whereas in the majority of cases this qualitative assessment is sufficient, it is of course subjective. Hence there is a clinical interest in the quantification of stiffness testing as well as image analysis.
1. The quantification of image analysis is worthwhile from two different points of view. The one is image analysis as a technique for the assessment of biological processes (eg scintigraphy for the follow up of bone growth). The other is quantitative image analysis in combination with a mechanical model to predict the stiffness and strength of a bony structure. Quantitative histomorphometry is currently developed to this purpose.
BMC (Bone Mineral Content) scanning and QCT (Quantitative Computer Tomography) can be used both to evaluate biological processes and to predict strength. These techniques have been applied in clinical research.
2. The quantification of stiffness testing is considered the most direct approach, since stiffness is expected to correlate directly with load bearing capacity.
Fracture stiffness tests can be subdivided into static tests and dynamic tests. Within the category of static tests we can distinguish between direct displacement measurements on the fractured bone and undirect load carrying tests using eg external or internal fixation systems
Dynamic tests can be subdivided into sonic and ultrasound tests. Sonic tests include shock wave propagation as well as vibration analysis. Whereas static testing measures pure stiffness, dynamic test data are affected by mass (density) characteristics as well.
Quantitative methods for fracture healing monitoring would have advantages over the conventional assessment methods for the following purposes:
1. To define on an objective scientific basis the endpoint of healing.
2. To evaluate quantitively the effect of different treatment regimes: eg electrical or mechanical stimulation.
3. To evaluate bone consolidation after elongation or osseous integration after bone grafting.
4. To identify complications or abnormalities in fracture healing in an early stage.