Associate Professor in Residence
Email: jhkeyak@uci.edu
Dr. Keyak's CV
Dr. Keyak’s main clinical interests relate to
osteoporosis and metastatic tumors in bone. As
a bioengineer, she has applied the principles of engineering
structural analysis to bone and other materials, with
the goal of improving our understanding and treatment
of orthopaedic problems. Dr. Keyak is particularly
interested in the assessment of pathological fracture
risk for bone (due to tumors or osteoporosis), the effect
of radiation on bone strength, and development of minimally
invasive treatments for bone with metastatic tumors.
Dr. Keyak has also studied the design and evaluation
of prosthetic implants and bone remodeling.
Dr. Keyak pioneered a technique for rapidly creating
patient-specific structural engineering models (finite
element models) of the hip. This technique and variations
of it are now used around the world to study bone. Dr.
Keyak's current research often relies on this modeling
technique and is directed toward improving the lives
of patients with bone disease.
A major focus of this research is to develop non-invasive
methods for estimating bone strength and assessing fracture
risk for patients with osteoporosis or other pathological
conditions. The tools used for predicting bone strength
may also help improve our understanding of bone fracture
and may lead to the development of methods for preventing
it. This work has carried over to other areas of orthopaedic
research, including the effect of radiation and spaceflight
on bone strength, the study of bone remodeling, and
design and analysis of prosthetic implants. Dr. Keyak
is involved with the UC Irvine Space Cycle and is investigating
the effect of simulated hypergravity on bone (http://spacecycle.hs.uci.edu).
Dr. Keyak is also developing minimally invasive techniques
for treating bones with metastatic tumors from breast,
prostate, lung, or other cancers. Special techniques
used in this research include quantitative computed
tomography for non-invasive collection of geometry and
material property data, automated generation of finite
element models, and mechanical testing of whole bones.
Dr. Keyak is currently developing a new method of radiation
therapy for bone with metastatic tumors and has co-founded
a start-up company, Bone-Rad Therapeutics, Inc. (http://www.bone-rad.com),
to bring this treatment to market.
View Dr. Keyak's Research Program
Dr. Keyak received her undergraduate degree in mechanical
engineering from the University of California, Berkeley
and her doctorate in bioengineering at UC San Francisco
and UC Berkeley. She currently serves as an Associate
Professor in Residence in the Department of Orthopaedic
Surgery at the University of California, Irvine.
Dr. Keyak also has faculty appointments in the Department of
Mechanical and Aerospace Engineering and in the Department
of Biomedical Engineering and is a member of the UC
Irvine Space Cycle Team (http://spacecycle.hs.uci.edu).
She serves on the UC Irvine Division Representative
Assembly of the Academic Senate; UCI Council on the
Student Experience; School of Medicine Planning, Budget
and Facilities Committee; School of Medicine, Promotions
and Honors Committee; UC Irvine Willed Body Program
Advisory Committee; Department of Biomedical Engineering
Faculty Recruitment Committee; and Mathematical and
Computational Biology Gateway Graduate Program Executive
Committee.
She serves on the editorial boards of Medical Engineering
& Physics and Journal of Biomechanics. She
also reviews manuscripts for Clinical Orthopaedics
and Related Research and ASME Journal of Biomechanical
Engineering. She has also reviewed grant applications
for the National Institutes of Health and for a number
of organizations around the world.
Bioengineering, UC San Francisco and UC Berkeley
1. Keyak JH, Meagher JM, Skinner HB, Mote CD, Jr.: Automated three-dimensional finite element modelling of bone: A new method. J Biomed Eng 12(5):389-397, 1990.
2. Anderson MJ, Keyak JH, Skinner HB: Compressive mechanical properties of human cancellous bone after gamma irradiation. J Bone Joint Surg [Am] 74-A(5):747-752, 1992.
3. Keyak JH, Skinner HB: Three-dimensional finite element modeling of bone: Effects of element size. J Biomed Eng 14(6):483-489, 1992.
4. Lee IY, Skinner HB, Keyak JH: Effects of variation of cement thickness on bone and cement stress at the tip of a femoral implant. Iowa Orthop J 13:155-159, 1993.
5. Keyak JH, Fourkas MG, Meagher JM, Skinner HB: Validation of an automated method of three-dimensional finite element modelling of bone. J Biomed Eng 15:505-509, 1993.
6. Les CM, Keyak JH, Stover SM, Taylor KT, Kaneps AJ: Estimation of material properties in the equine metacarpus with use of quantitative computed tomography. J Orthop Res 12:822-833, 1994.
7. Bozic KJ, Keyak JH, Skinner HB, Bueff HU, Bradford DS: Three-dimensional finite element modeling of a cervical vertebra: An investigation of burst fracture mechanism. J Spinal Disorders 7(2):102-110, 1994.
8. Keyak JH, Lee IY, Skinner HB: Correlations between orthogonal mechanical properties and density of trabecular bone: Use of different densitometric measures. J Biomed Mater Res 28(11):1329-1336, 1994.
9. Lee IY, Skinner HB, Keyak JH: Effects of variation of prosthesis size on bone and cement stress at the tip of a femoral implant. J Biomed Mater Res 28:1055-1060, 1994.
10. Skinner HB, Kilgus DJ, Keyak JH, Shimaoka EE, Kim AS, Tipton JS: Correlation of computed finite element stresses to bone density after remodeling around cementless femoral implants. Clin Orthop Relat Res 305:178-189, 1994.
11. Skinner HB, Kim AS, Keyak JH, Mote CD, Jr.: Femoral prosthesis implantation induces changes in bone stress that depend on extent of porous coating. J Orthop Res 12:553-563, 1994.
12. Jergas MD, Majumdar S, Keyak JH, Lee IY, Newitt DC, Grampp S, Skinner HB, Genant HK: Relationships between young modulus of elasticity, ash density, and MRI derived transverse relaxation T2* in tibial specimens. J Comput Assist Tomgr 19(3):472-479, 1995.
13. Majumdar S, Newitt DC, Jergas M, Gies A, Chiu EJ, Osman D, Keltner J, Keyak J, Genant HK: Evaluation of technical factors affecting the quantification of trabecular bone structure using magnetic resonance imaging. Bone 17(4):417-430, 1995.
14. Keyak JH, Lee IY, Nath DS, Skinner HB: Postfailure compressive behavior of tibial trabecular bone in three anatomic directions. J Biomed Mater Res 31:373-378, 1996.
15. Les CM, Stover SM, Keyak JH, Taylor KT, Willits NH: The distribution of material properties in the equine third metacarpal bone serves to enhance sagittal bending. J Biomech 30:355-361, 1997.
16. Les CM, Keyak JH, Stover SM, Taylor KT: Development and validation of a series of three-dimensional finite element models of the equine metacarpus. J Biomech 30:737-742, 1997.
17. Lang TF, Keyak JH, Heitz MW, Augat P, Lu Y, Mathur A, Genant HK: Volumetric quantitative computed tomography of the proximal femur: precision and relation to bone strength. Bone 21:101-108, 1997.
18. Les CM, Stover SM, Taylor KT, Keyak JH, Willits NH: Ex vivo simulation of in vivo strain distributions in the equine metacarpus. Eq Vet J 30(3):260-266, 1998.
19. Namba RS, Keyak JH, Kim AS, Vu LP, Skinner HB: Cementless implant composition and femoral stress: A finite element analysis. Clin Orthop Rel Res 347:261-267, 1998.
20. Keyak JH, Rossi SA, Jones KA, Skinner HB: Prediction of femoral fracture load using automated finite element modeling. J Biomech 31:125-133, 1998.
21. Powers CM, Lee IY, Skinner HB, Keyak JH: The effects of distal cement voids on cement stress in total hip arthroplasty. J Arthroplasty 13:793-798, 1998.
22. Keyak JH, Rossi SA: Prediction of femoral fracture load using finite element models: an examination of stress- and strain-based failure theories. J Biomech 33:209-214, 2000.
23. Keyak JH: Relationships between femoral fracture loads for two load configurations. J Biomech 33:499-502, 2000.
24. Keyak JH, Skinner HB, Fleming JA: Effect of force direction on femoral fracture load for two types of loading conditions. J Orthop Res 19:539-544, 2001.
25. Keyak JH: Improved prediction of proximal femoral fracture load using nonlinear finite element models. Med Eng Phys 23:165-173, 2001. [Corrigendum published 25:615, 2003.]
26. Kim JY, Rosenfeld SR, Keyak JH: Increased prevalence of scoliosis in Turner syndrome. J Pediatric Orthop 21:765-766, 2001.
27. Les CM, Keyak JH, Stover SM, Taylor KT, Kaneps AJ: Stiff and strong material properties are associated with brittle post-yield behavior in compact bone. J Orthop Res 20:607-614, 2002.
28. Keyak JH, Rossi SA, Jones KA, Les CM, Skinner HB: Prediction of fracture location in the proximal femur using finite element models. Med Eng Phys 23:657-664, 2001.
29. Samii VF, Les CM, Schulz KS, Keyak JH, Stover SM: Computed tomographic osteoabsorptiometry of the elbow joint in clinically normal dogs. Am J Vet Res 63(8):1159-1166, 2002.
30. Kaneko TS, Pejcic MR, Tehranzadeh J, Keyak JH: Relationships between material properties and CT scan data of cortical bone with and without metastatic lesions. Med Eng Phys 25:445-454, 2003.
31. Keyak JH, Falkinstein Y: Comparison of in situ and in vitro CT scan-based finite element model predictions of proximal femoral fracture load. Med Eng Phys 25(9):781-787, 2003.
32. Kaneko TS, Bell JS, Pejcic MR, Tehranzadeh J, Keyak JH: Mechanical properties, density, and quantitative CT scan data of trabecular bone with and without metastases. J Biomech 37(4):523-530, 2004.
33. Lian K, Lang TF, Keyak JH, Modin GW, Rehman Q, Do L, Lane NE: Differences in hip quantitative computed tomography (QCT) measurements of bone mineral density and bone strength between glucocorticoid-treated and glucocorticoid-naïve postmenopausal women. Osteoporosis Int 16:642-650, 2005. [Published online: 28 Sept 2004]
34. Keyak JH, Kaneko TS, Rossi SA, Pejcic MR, Tehranzadeh J, Skinner HB: Predicting the strength of femoral shafts with and without metastatic lesions. Clin Orthop Relat Res Oct (439):161-170, 2005.
35. Keyak JH, Kaneko TS, Tehranzadeh J, Skinner HB: Predicting proximal femoral strength using structural engineering models. Clin Orthop Relat Res Aug (437):219-228, 2005.
36. Meta M, Lu Y, Keyak JH, Lang T: Young-elderly differences in bone density, geometry and strength indices depend on proximal femur sub-region: a cross sectional study in Caucasian-American women. Bone 39(1):152-158, 2006. [Published online: 3Feb 2006]
37. Kaneko TS, Skinner HB, Keyak JH: Feasibility of
a percutaneous technique for repairing proximal femora
with simulated metastatic lesions. Med Eng Phys 29(5):594-601,
2007.
38. Cheng X, Li J, Lu Y, Keyak J, Lang T: Proximal
femoral density and geometry measurements by quantitative
computed tomography: association with hip fracture.
Bone40(1):169-74, 2007.
39. Yang Y, Kaplan A, Pierre M, Adams G, Cavanagh P,
Takahashi C, Kreitenberg A, Hicks J, Keyak J, Caiozzo
V: Space cycle: A human-powered centrifuge that can
be used for hypergravity resistance training. Aviat
Space Environ Med 78(1):2-9, 2007.
40. Keyak JH, Kaneko TS, Skinner HB, Hoang BH: Effect
of simulated metastatic lytic lesions on proximal femoral
strength. Clin Orthop Relat Res 459:139-145, 2007.
41. Kaneko TS, Skinner HB, Keyak JH: Lytic lesions in the femoral neck: Importance of location and evaluation of a novel minimally invasive repair technique. J Orthop Res. [Epub 2008 Mar 7]
42. Yang GY, Johnson G, Tang WC, and Keyak JH: Parylene-based strain sensor for bone. Sensors 7(12):1693-97, 2007.
43. Li W, Kezele I, Collins DL, Zijdenbos A, Keyak J, Kornak J, Koyama A, Saeed I, LeBlanc A, Harris T, Lu Y, Lang T: Voxel-based modeling and quantification of the proximal femur using inter-subject registration of quantitative CT images. Bone 41(5):888-95, 2007. [Epub 2007 Jul 17]
44. Lang TF, Koyama A, Li C, Li J, Lu Y, Saeed I, Gazze E, Keyak JH, Harris TB, Cheng X: Pelvic body composition measurements by quantitative computed tomography: Association with recent hip fracture. Bone 42(4):798-805, 2008. [Epub 2008 Jan 30]
45. Langton CM, Pisharody S, Mathers C, Keyak JH: Generation of a 3D proximal femur shape from a single projection 2D radiographic image. Osteoporosis Int. Accepted.
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Joyce Keyak, Ph.D
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