Related Experiment Video
Updated: May 13, 2026
A Reliable and Reproducible Critical-Sized Segmental Femoral Defect Model in Rats Stabilized with a Custom External Fixator
Published on: March 24, 2019
Fixation of non-cemented total hip arthroplasty femoral components in a simulated proximal bone defect model
Sophia N Sangiorgio1, Edward Ebramzadeh, Ashleen R Knutsen
1The J. Vernon Luck, Sr. Orthopaedic Research Center, Los Angeles Orthopaedic, Hospital/UCLA, Los Angeles, California; UCLA and Orthopaedic Hospital Department of Orthopaedic Surgery, University of California, Los Angeles, California.
Abstract:
An accelerated sequential proximal femoral bone loss model was used to measure the initial stability of three noncemented femoral stem designs: fully porous-coated, proximally porous-coated, and dual-tapered, diaphyseal press-fit (N=18). Only dual-tapered, diaphyseal press-fit stems remained stable with as much as 105 mm of bone loss, with average cyclic micromotion remaining below 25 μm in ML and below 10 μm in AP planes. In contrast, with proximally coated and fully coated stem designs with circular or oval cross-sections, 60mm of bone loss, resulting in lower than 10 cm of diaphyseal bone contact length, led to gross instability, increasing average cyclic micromotions to greater than 100 μm prior to failure. Therefore, the results provide support for using a dual-tapered stem in revision cases with proximal bone loss.
