Scope
To design or develop orthopaedic implants, particularly joint replacements intended to function for the lifetime of patients, many material and design criteria must be considered. These include adequate strength to avoid fatigue failure, appropriate geometry and positioning to permit adequate range of motion without impingement that can damage the implant and lead to loosening, secure fixation to bony structures, whether achieved by cementing or bone ingrowth, minimizing micromotion and fretting wear between the components of the implant or between the implant and bone, and many others.
Research
The researchers of the Implant Biomechanics Lab develop models that simulate the mechanical conditions experienced by an implant and its surrounding bone and soft tissues in a patient under various activities. They use these models to evaluate and improve different implant designs, surgical treatments or fixation methods. These models are typically made with analog bone models and/or soft tissues (or cadaveric specimens). Loads and torques in different planes encountered during specific activities are simulated using sophisticated, computer-controlled servo-hydraulic load frames. Loading apparatuses designed and developed in the Implant Biomechanics Lab are capable of being used to evaluate strength and fixation of artificial hip, knee and spine implants.
Apparatus
In addition, a three-station artificial disc simulator is used to evaluate fatigue strength of elastomeric types of artificial discs. An 8-degree-of-freedom MTS spine flexibility tester allows evaluation of spinal injuries, surgical procedures including various fusion methods, or the effectiveness of spinal constructs and fixation devices.
Staff
The Implant Performance Laboratory is under the direction of Edward
Ebramzadeh, Ph.D., and includes Sophia Sangiorgio, Ph.D., Laboratory
Manager. Jessica Lee, a graduate student from USC Department of
Biomedical Engineering is conducting research towards her Ph.D. degrees
in the laboratory.
Selected Publications
- Ebramzadeh, E.; McKellop, H.; Dorey, F.; and Sarmiento, A.: Challenging the validity of conclusions based on P-values alone: a critique of contemporary clinical research design and methods. Instr Course Lect, 43: 587-600, 1994
- Ebramzadeh, E., Sangiorgio, S.N., Longjohn, D.B., Buhari, C.F., Dorr, L.D.: Initial stability of cemented femoral stems as a function of surface finish, collars, and stem size. J Bone and Joint Surg, Am, 2004. Jan;86-A (1): 106-115.
- Ebramzadeh, E., Sangiorgio, S.N., Lattuada, F, Kang, J-S, Chiesa, R., McKellop, H.A., Dorr, L.D.:Accuracy of methods for measurement of polyethylene wear from radiographs of total hip replacements. J Bone and Joint Surg, Am, 2004. Dec; 85-A (12):2378-2384.
- Sangiorgio, S.N., Ebramzadeh, E., Longjohn, D.B., Dorr, L.D.: Effects of Dorsal Flanges on Fixation of a Cemented Total Hip Replacement Femoral Stem. J Bone Joint Surg Am. 2004 Apr;86(4):813-820.
- Ebramzadeh, E., Sangiorgio, S.N., Clarke, I.C.: Greater Expectations and Greater Joint Loads in Modern Total Joint Arthroplasty Patients, in Core Knowledge in Orthopedics: Adult Reconstruction and Arthroplasty, edited by Jonathan Garino and Pedro Beredjiklian. Published by Elsevier in Philadelphia, 2006.
Contact
Eddie Ebramzadeh, Ph.D., eebramzadeh@laoh.ucla.edu, tel: (213) 742-1378
Continue: Implant Tribology
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Evaluating micromotion at implant-bone interface
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