Kenneth A Mann, PhD
Research Programs and Affiliations
- Biomedical Sciences Program
- Cancer Research Institute
- Neuroscience and Physiology
- Orthopedic Surgery
- Physiology Program
- Research Pillars
Education & Fellowships
- PhD: Cornell University, 1991, Mechanical Engineering (Biomechanics)
- MS: Pennsylvania State University, 1985, Bioengineering
- BS: Virginia Tech, 1983, Engineering Science and Mechanics
- Micro-mechanics of implant interfaces; damage evolution of joint replacements and biomaterials; in vivo models of tumor osteolysis and prediction of fracture risk; general orthopedic biomechanics.
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Micromechanics and micro-mechanical modeling of bone-implant interfaces: Implant fixation is vital to long-term success of mechanically loaded implant systems. Surprisingly little is known about the load transfer mechanisms and motion at the length scales of trabeculae (~1mm) and below. We have been performing in vitro experiments on small components of bone-implant interfaces in which small (micron scale) loading is applied in tension, compression, and shear. We incorporate digital image correlation techniques to map local strain fields subjected to loading. The long-term goal here is to improve our understanding of local motions at the interface and how motion is related to bony response. Both experimental and computational models are performed on laboratory prepared and post-mortem retrieved specimens. (NIH funded).
Damage evolution of musculoskeletal systems: Repetitive loading of implant systems can result in early loosening. In fact, early motion (stability) of implant systems is an excellent predictor of long term viability of implants. We have been studying damage evolution to PMMA cement that is used to fix implants to bone. Through a combination of experimental work and companion modeling efforts, we are developing improved computational tools to predict long term success of joint replacements. (NIH funded).
Controlled delivery of BMPs on biomaterials: Bone morphogenic proteins have been used successfully to enhance bone formation. We have been investigating the short-term success of bony ingrowth into metallic implant surfaces using BMPs. One important aspect of BMP delivery is to control both the dose and the time release to prevent ectopic bone formation. We have been working on delayed release systems that can be readily adapted to existing metallic implants. (NASA-Biotech and Corporate funding).
Biomechanical assays to investigate skeletal tumor burden and development of surrogates of bone strength: Bone is a common site for metastases of primary tumors such as breast, prostate, ovarian, lung, and colon cancer. A collaborator (M Allen) has developed a model of breast cancer to bone in a murine model. We have been using this model to directly assess biomechanical strength and relate this to existing paradigms used in clinical medicine. In addition we are developing indirect biomechanical assays or surrogates of bone strength using voxel-based finite element modeling approaches coupled with in vivo imaging. This work has the potential to improve our ability to predict which clinical patients require surgical reconstruction and also to monitor how patients are responding to radiation and anti-resorptive or anabolic drug therapies. (Funding from Baldwin Foundation.)
Role of therapeutic radiation in increasing fracture risk of bone: Using a murine model of radiation damage to the femur we are investigating the implications of bony remodeling in terms of structure and fundamental changes to bone material fracture resistance. We are using nano-indentation to quantify elastic and inelastic behavior of trabecular and cortical bone. We are also using a combination of voxel-based finite element modeling with material damage models and comparing these to experiments to gain a better understanding of bone 'brittle' behavior. (Funding by: Baldwin Foundation)
Recent Representative Publication
- Mann KA, Miller MA, Pray CL, Verdonschot N, Janssen D. A new approach to quantify trabecular resorption adjacent to cemented knee arthroplasty. Journal of Biomechanics, 45: 711-715, 2012.
- Mann KA, Miller MA, Khorasani, M, Townsend KL, Allen MJ. The dog as a preclinical model to evaluate interface morphology and micro-motion in total knee replacement. Vet Comp Orthop Traumatol, 25(1):1-10, 2012.
- Mann KA, Miller MA, Costa PA, Race A, Izant TH. Interface micromotion of uncemented femoral components from postmortem retrieved total hip replacements. J Arthroplasty, 27(2):238-245, 2012.
- Race A, Miller MA, Izant TH, Mann KA. Direct evidence of damage accumulation in cement mantles surrounding femoral stems retrieved at autopsy: cement damage correlates with duration of use and BMI. J Biomechanics, 44(13):2345-50, 2011.
- Waanders D, Janssen D, Mann KA, Verdonschot N. Morphology based cohesive zone modeling of the cement-bone interface from postmortem retrievals. J Mechanical Behavior of Biomedical Materials, 4:1492-1503, 2011.
- Cooper WJ, Wernle J, Mann KA, Albertson RC. Functional and genetic integration in the skulls of Lake Malawi Cichlids. Evolutionary Biology, 38(3): 316-334, 2011. DOI: 10.1007/s11692-011-9124-9
- Parmentier E, Mann KA, Mann DA. Hearing and morphological specializations of the mojarra (Eucinostomus argentus). J Experimental Biology, 214: 2697-2701, 2011.
- Waanders D, Janssen D, Mann KA, Verdonschot N. The behavior of the micro-mechanical cement-bone interface affects the cement failure in total hip replacement. J Biomechanics, 44(2): 228-234, 2011.
- Waanders D, Janssen D, Bertoldi K, Mann KA, Verdonschot N. Mixed-mode loading of the cement-bone interface: A finite element study. Computer Methods in Biomechanics and Biomedical Engineering, 14(2):145-55, 2011.
- Miller MA, Race A, Waanders D, Cleary R, Janssen D, Verdonschot N, Mann KA. Multi-axial loading micromechanics of the cement-bone interface in post-mortem retrievals and lab-prepared specimens. J Mechanical Behavior of Biomedical Materials, 4(3): 366-74, 2011.