Pathological fracture of the femur is a common and serious consequence of metastatic cancer of the breast, lung, prostate, kidney and thyroid. Surgical fixation is used to prevent pathological fracture when a patient is thought to be at high risk of fracture. However, current methods for identifying patients in need of fixation involve only simple rules of thumb, such as destruction of more than 50% of the cortex, or diameter greater than 2.5 cm, and have been shown to be inadequate. To address this issue, this study will explore the feasibility of using a new imaging/computational technique for assessing the risk of pathological fracture of the femur. This technique will employ automatically generated, computed tomographic (CT) scan-based finite element (FE) models to estimate the strength (fracture loads) of proximal femora and femoral shafts with metastatic lesions. This will be the first study in which FE modeling has been used to compute fracture loads for bones with actual metastatic tumors.
Specific Aims of this study are to evaluate the accuracy and precision of this automated CT/FE technique, in the context of tumor-involved bones, by computing and measuring fracture loads in vitro for: (a) eight femoral shafts with metastatic lesions tested in four-point bending; (b) eight femoral shafts with metastatic lesions tested in torsion; and (c) ten proximal femora with metastatic lesions under joint loading similar to that during single-limb stance. If this new imaging/ computational technique successfully predicts fracture loads of femora with metastatic lesions, the next step would be to relate the CT/FE-computed fracture loads to fracture risk. The long-term goal will be to implement this technique in the clinical setting so that the incidence of both pathological fracture and unnecessary prophylactic fixation can be reduced, with a concomitant reduction in health care costs. It is suggested (by the applicant) that this CT/FE technique would also be useful for basic science research to help better understand the interaction of bone mechanics, tumors and bone response.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21CA079568-01
Application #
2727132
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Program Officer
Menkens, Anne E
Project Start
1998-12-01
Project End
2000-11-30
Budget Start
1998-12-01
Budget End
1999-11-30
Support Year
1
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of California Irvine
Department
Orthopedics
Type
Schools of Medicine
DUNS #
161202122
City
Irvine
State
CA
Country
United States
Zip Code
92697
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Keyak, Joyce H; Kaneko, Tadashi S; Skinner, Harry B et al. (2007) The effect of simulated metastatic lytic lesions on proximal femoral strength. Clin Orthop Relat Res 459:139-45
Kaneko, Tadashi S; Skinner, Harry B; Keyak, Joyce H (2007) Feasibility of a percutaneous technique for repairing proximal femora with simulated metastatic lesions. Med Eng Phys 29:594-601
Keyak, Joyce H; Kaneko, Tadashi S; Rossi, Stephen A et al. (2005) Predicting the strength of femoral shafts with and without metastatic lesions. Clin Orthop Relat Res 439:161-70
Keyak, Joyce H; Kaneko, Tadashi S; Tehranzadeh, Jamshid et al. (2005) Predicting proximal femoral strength using structural engineering models. Clin Orthop Relat Res :219-28
Kaneko, Tadashi S; Bell, Jason S; Pejcic, Marina R et al. (2004) Mechanical properties, density and quantitative CT scan data of trabecular bone with and without metastases. J Biomech 37:523-30
Kaneko, Tadashi S; Pejcic, Marina R; Tehranzadeh, Jamshid et al. (2003) Relationships between material properties and CT scan data of cortical bone with and without metastatic lesions. Med Eng Phys 25:445-54
Keyak, Joyce H; Falkinstein, Yuri (2003) Comparison of in situ and in vitro CT scan-based finite element model predictions of proximal femoral fracture load. Med Eng Phys 25:781-7