Edward Ebramzadeh
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Edward Ebramzadeh has a total of 23 co-authors. Here are the top co-authors by number of shared publications:
Sophia N. Sangiorgio
Biomechanics Laboratory of the J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Los Angeles Orthopaedic Hospital∕UCLA and The Dorr Arthritis Institute of Centinela Hospital, Inglewood, California
4 shared publicationsLawrence D. Dorr
3 shared publicationsDonald B. Longjohn
2 shared publications- Adolfo Llinás
Department of Orthopedics and Traumatology, Hospital Universitario Fundación Santa Fe de Bogotá, Bogotá, Colombia
1 shared publication - Ashleen Knutsen
The J. Vernon Luck Research Center, Orthopaedic Institute for Children, 403 W. Adams Blvd., Los Angeles, CA, 90007, USA,
1 shared publication Augusto Sarmiento
Biomechanics Laboratory, The J Vernon Luck Center for Orthopaedic Research, Los Angeles Orthopaedic Hospital/UCLA, USA
1 shared publication
Latest Publications
- Open Access
- 1 February 2014
- Published by SAGE Publications in Journal of Children's Orthopaedics
- Vol. 8 (1) , 83-89
Accuracy of radiographs in assessment of displacement in lateral humeral condyle fractures
Purpose: Determining the magnitude of displacement in pediatric lateral humeral condyle fractures can be difficult. The purpose of this study was to (1) assess the effect of forearm rotation on true fracture displacement using a cadaver model and to (2) determine the accuracy of radiographic measurements of the fracture gap. Methods: A non-displaced fracture was created in three human cadaveric arms. The specimens were mounted on a custom apparatus allowing forearm rotation with the humerus fixed. First, the effect of pure rotation on fracture displacement was simulated by rotating the forearm from supination to pronation about the central axis of the forearm, to isolate the effects of muscle pull. Then, the clinical condition of obtaining a lateral oblique radiograph was simulated by rotating the forearm about the medial aspect of the forearm. Fracture displacements were measured using a motion-capture system (true-displacement) and clinical radiographs (apparent-displacement). Results: During pure rotation of the forearm, there were no significant differences in fracture displacement between supination and pronation, with changes in displacement of <1.0 mm. During rotation about the medial aspect of the forearm, there was a significant difference in true displacements between supination and pronation at the posterior edge ( p < 0.05). Conclusion: Overall, true fracture displacement measurements were larger than apparent radiographic displacement measurements, with differences from 1.6 to 6.0 mm, suggesting that the current clinical methods may not be sensitive enough to detect a displacement of 2.0 mm, especially when positioning the upper extremity for an internal oblique lateral radiograph.
- 1 February 2014
- Published by SAGE Publications in Journal of Children's Orthopaedics
- Vol. 8 (1) , 83-89
Open AccessAccuracy of radiographs in assessment of displacement in lateral humeral condyle fractures
Purpose: Determining the magnitude of displacement in pediatric lateral humeral condyle fractures can be difficult. The purpose of this study was to (1) assess the effect of forearm rotation on true fracture displacement using a cadaver model and to (2) determine the accuracy of radiographic measurements of the fracture gap. Methods: A non-displaced fracture was created in three human cadaveric arms. The specimens were mounted on a custom apparatus allowing forearm rotation with the humerus fixed. First, the effect of pure rotation on fracture displacement was simulated by rotating the forearm from supination to pronation about the central axis of the forearm, to isolate the effects of muscle pull. Then, the clinical condition of obtaining a lateral oblique radiograph was simulated by rotating the forearm about the medial aspect of the forearm. Fracture displacements were measured using a motion-capture system (true-displacement) and clinical radiographs (apparent-displacement). Results: During pure rotation of the forearm, there were no significant differences in fracture displacement between supination and pronation, with changes in displacement of <1.0 mm. During rotation about the medial aspect of the forearm, there was a significant difference in true displacements between supination and pronation at the posterior edge ( p < 0.05). Conclusion: Overall, true fracture displacement measurements were larger than apparent radiographic displacement measurements, with differences from 1.6 to 6.0 mm, suggesting that the current clinical methods may not be sensitive enough to detect a displacement of 2.0 mm, especially when positioning the upper extremity for an internal oblique lateral radiograph.
- 2 January 2005
- Published by ASME International in Journal of Biomechanical Engineering
- Vol. 127 (3) , 357-363
Simulation of Fretting Wear at Orthopaedic Implant Interfaces
Osteolysis due to wear debris is a primary cause of failure of total joint replacements. Although debris produced by the joint articulating surfaces has been studied and simulated extensively, fretting wear debris, produced at nonarticulating surfaces, has not received adequate attention. We developed a three-station fretting wear simulator to reproduce in vivo motion and stresses at the interfaces of total joint replacements. The simulator is based on the beam bending theory and is capable of producing cyclic displacement from , under varying magnitudes of contact stresses. The simulator offers three potential advantages over previous studies: The ability to control the displacement by load, the ability to produce very small displacements, and dynamic normal loads as opposed to static. A pilot study was designed to test the functionality of the simulator, and verify that calculated displacements and loads produced the predicted differences between two commonly used porous ingrowth titanium alloy surfaces fretting against cortical bone. After 1.5 million cycles, the simulator functioned as designed, producing greater wear of bone against the rougher plasma-sprayed surface compared to the fiber-mesh surface, as predicted. A novel pin-on-disk apparatus for simulating fretting wear at orthopaedic implant interfaces due to micromotion is introduced. The test parameters measured with the fretting wear simulator were as predicted by design calculations, and were sufficient to measure differences in the height and weight of cortical bone pins rubbing against two porous ingrowth surfaces, plasma-sprayed titanium and titanium fiber mesh.- 2 January 2005
- Published by ASME International in Journal of Biomechanical Engineering
- Vol. 127 (3) , 357-363
Simulation of Fretting Wear at Orthopaedic Implant Interfaces
Osteolysis due to wear debris is a primary cause of failure of total joint replacements. Although debris produced by the joint articulating surfaces has been studied and simulated extensively, fretting wear debris, produced at nonarticulating surfaces, has not received adequate attention. We developed a three-station fretting wear simulator to reproduce in vivo motion and stresses at the interfaces of total joint replacements. The simulator is based on the beam bending theory and is capable of producing cyclic displacement from , under varying magnitudes of contact stresses. The simulator offers three potential advantages over previous studies: The ability to control the displacement by load, the ability to produce very small displacements, and dynamic normal loads as opposed to static. A pilot study was designed to test the functionality of the simulator, and verify that calculated displacements and loads produced the predicted differences between two commonly used porous ingrowth titanium alloy surfaces fretting against cortical bone. After 1.5 million cycles, the simulator functioned as designed, producing greater wear of bone against the rougher plasma-sprayed surface compared to the fiber-mesh surface, as predicted. A novel pin-on-disk apparatus for simulating fretting wear at orthopaedic implant interfaces due to micromotion is introduced. The test parameters measured with the fretting wear simulator were as predicted by design calculations, and were sufficient to measure differences in the height and weight of cortical bone pins rubbing against two porous ingrowth surfaces, plasma-sprayed titanium and titanium fiber mesh.- 1 April 2004
- Published by Wolters Kluwer Health in Journal of Bone and Joint Surgery
- Vol. 86 (4) , 813-820
EFFECTS OF DORSAL FLANGES ON FIXATION OF A CEMENTED TOTAL HIP REPLACEMENT FEMORAL STEM
Background:Although current designs of cemented femoral stems for total hip replacement include both those with and those without a flanged shape at the proximal end, the influence of anteroposterior dorsal flanges on the fixation of the stem is not completely understood. The purpose of this study w
- 1 April 2004
- Published by Wolters Kluwer Health in Journal of Bone and Joint Surgery
- Vol. 86 (4) , 813-820
EFFECTS OF DORSAL FLANGES ON FIXATION OF A CEMENTED TOTAL HIP REPLACEMENT FEMORAL STEM
Background:Although current designs of cemented femoral stems for total hip replacement include both those with and those without a flanged shape at the proximal end, the influence of anteroposterior dorsal flanges on the fixation of the stem is not completely understood. The purpose of this study w
- 1 January 2004
- Published by Wolters Kluwer Health in Journal of Bone and Joint Surgery
- Vol. 86 (1) , 106-115
Initial Stability of Cemented Femoral Stems as a Function of Surface Finish, Collar, and Stem Size
Background:The optimum surface roughness of cemented femoral stems used for total hip replacement is a subject of controversy. While rougher surfaces provide stronger cement adhesion, it has been hypothesized that polished, tapered, noncollared stems settle into the cement mantle, providing improved
- 1 January 2004
- Published by Wolters Kluwer Health in Journal of Bone and Joint Surgery
- Vol. 86 (1) , 106-115
Initial Stability of Cemented Femoral Stems as a Function of Surface Finish, Collar, and Stem Size
Background:The optimum surface roughness of cemented femoral stems used for total hip replacement is a subject of controversy. While rougher surfaces provide stronger cement adhesion, it has been hypothesized that polished, tapered, noncollared stems settle into the cement mantle, providing improved
- 1 December 2003
- Published by Wolters Kluwer Health in Journal of Bone and Joint Surgery
- Vol. 85 (12) , 2378-2384
ACCURACY OF MEASUREMENT OF POLYETHYLENE WEAR WITH USE OF RADIOGRAPHS OF TOTAL HIP REPLACEMENTS
Background:Although a number of methods are used to estimate polyethylene liner wear from radiographs of total hip replacements, there is no consensus with regard to the accuracy of these methods. The purpose of this study was to compare the accuracy of several such measurement methods with use of b
- 1 December 2003
- Published by Wolters Kluwer Health in Journal of Bone and Joint Surgery
- Vol. 85 (12) , 2378-2384
ACCURACY OF MEASUREMENT OF POLYETHYLENE WEAR WITH USE OF RADIOGRAPHS OF TOTAL HIP REPLACEMENTS
Background:Although a number of methods are used to estimate polyethylene liner wear from radiographs of total hip replacements, there is no consensus with regard to the accuracy of these methods. The purpose of this study was to compare the accuracy of several such measurement methods with use of b
- 1 August 2003
- Published by Elsevier in Biomaterials
- Vol. 24 (19) , 3351-3363
Long-term radiographic changes in cemented total hip arthroplasty with six designs of femoral components
- 1 August 2003
- Published by Elsevier in Biomaterials
- Vol. 24 (19) , 3351-3363
Long-term radiographic changes in cemented total hip arthroplasty with six designs of femoral components