Services and Facilities of the Orthopaedic Research Laboratory
Radboud university medical center
To facilitate research the lab has ample computer facilities to perform complex in silica analyses, has a mechanical test facility for practical bench testing and has its own histology and cell culture lab.
The services of the lab are:
– Biomechanical Testing of Orthopaedic Implants
– Computational Analysis using Finite Element Modelling
– Animal Models
– Histological Analysis
Biomechanical Testing of Orthopaedic Implants
We perform biomechanical tests to evaluate the performance of prosthetic joint designs. We are equipped with several mechanical testing systems to test the endurance and fixation strength of implants and devices. The lab furthermore has electromagnetic and RSA-based systems to analyze the functionality and kinematics of (artificial) joints. We have also developed custom testing rigs to evaluate knee implants and their effect on knee kinematics. A dedicated bioreactor is available for mechanical testing of hard and soft tissues in a controlled environment.
Mechanical loading machines: loading machines are used for mechanical analysis of failure, fatigue and stability properties. Also non-destructive tests can be performed to analyze elastic or visco-elastic behavior of materials or of cultured constructs. Two material testing systems (MTS) loading machines are available: one which can apply smaller loads, but at a high frequency. The other can apply higher loads (up to 10.000 N), but at lower frequencies. In the culture lab a Bose Electroforce system is available, which is based on the well known loudspeaker technology of Bose. With this system contructs for tissue engineering can be loaded during culture with relatively small loads (up to 100 N).
Knee test apparatus: to enable static and kinematic loaded experiments the ORL has two knee test apparatus. Since it is entirely composed of plastic, one apparatus is particularly useful for the analysis of static loading regimes in combination with 3Space Fastrak analysis.
RSA: RSA stands for Röntgen Stereogrammatical Analysis. It is a method with which relative positions of objects and displacements between objects can be calculated. The method can achieve an accuracy of 50 micron. RSA is particularly used for the assessment of displacements of implants relative to bones under static or dynamic loading conditions.
3Space Fastrak: Fastrak is a system which measures 3-dimensional position and orientation. The system is based on electro-magnetism and consists of a source and a sensor. The source creates a known electromagnetic field, which strength and direction is measured by the sensor. These measurements are translated to position and orientation of the sensor through hardware. As the system is based on electro-magnetism, the electric field can easily be disturbed by metal nearby (watch, keys). Four sensors can be used at the same time. Three sensors are available at the Orthopaedic Research Lab.
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Computational Analysis using Finite Element Modelling
The Orthopaedic Research Lab is specialized in computational modeling of orthopaedic applications of the hip and knee joint and of the spine, but also performs analysis on the strength of bone tissue. We perform both linear and non-linear analyses, focusing on implant performance, fixation, kinematics and wear. In addition, we simulate bone adaptation after the insertion of orthopaedic devices (remodeling), and perform analyses to predict the strength of bone affected by osteoporosis or bone tumors.
Finite Element Analysis: the lab has a large expertise and experience in finite element modelling of bony, bone-implant structures and more recently soft tissue components. Examples of FE-simulations are: long term damage accumulation and creep around cemented hip implants, long term bone remodelling, frictional heat generation, thermal shrinkage and creep in dental composites and FE-analysis of bone on micro-level. More recently the ORL started to develop Finite element models of musculoskeletal systems and of the knee.
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For in vivo testing of orthopaedic devices or procedures we have access to the central animal laboratory of the Radboud University Medical Centre Nijmegen. The animal laboratory offers expertise and facilities, such as medical imaging, to support animal testing for orthopaedic applications. In vivo evaluation is possible for animal models ranging from small (rats, mice) to larger (goat).
The orthopedic research laboratory has developed various animal models for cartilage, meniscus and bone research in small and large animals. In dogs we developed a model for tear meniscus repair. In goats we developed a number of bone chamber models to investigate the incorporation of bone grafts and bone graft replacement materials. Both loaded and (see PhD thesis of Lamerigts) and non-loaded bone chamber models were developed (see thesis of Hannink).
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The Orthopaedic Research Lab is fully equipped to perform histological and histomorphometrical analyses of both hard and soft tissues. We have a wide array of special stains for bone, cartilage and meniscus tissue. We can also offer digital photography of specimens for light and fluorescent microscopy, and for scanning electron microscopy.
Histology and cell culture facilities: to enable studies on regeneration of bone and cartilage tissue by tissue engineering the lab has its own cell culture and histology facilities. The ORL has a expertise on processing hard tissues and implant retrieval studies and has therefore various heavy duty microtome’s. Also histochemical and immunohistochemical techniques are performed. Within the lab also quantitative microscopy and (scanning) electron microscopy are available. Within research related to cartilage the lab cooperates with the Rheumatology Department and with the Matrix Biochemistry group.
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