Related Experiment Video
Updated: Mar 14, 2026

An Intramedullary Locking Nail for Standardized Fixation of Femur Osteotomies to Analyze Normal and Defective Bone Healing in Mice
Published on: November 13, 2016
The effect of intramedullary pin size and plate working length on plate strain in locking compression plate-rod
Tim Pearson1, Mark R Glyde, Robert E Day
1Dr. Tim Pearson, BVSc, MANZCVS, GradDipEd, MVetClinStud, MVetSurg, Western Australian Veterinary Emergency & Specialty (WAVES), Perth, Western Australia, Australia, Phone: +618 9412 5700,
Objective:
To investigate the effect of intramedullary pin size and plate working length on plate strain in locking compression plate-rod constructs.
Methods:
A synthetic bone model with a 40 mm fracture gap was used. Locking compression plates with monocortical locking screws were tested with no pin (LCP-Mono) and intramedullary pins of 20% (LCPR-20), 30% (LCPR-30) and 40% (LCPR-40) of intramedullary diameter. Two screws per fragment modelled a long (8-hole) and short (4-hole) plate working length. Strain responses to axial compression were recorded at six regions of the plate via three-dimensional digital image correlation.
Results:
The addition of a pin of any size provided a significant decrease in plate strain. For the long working length, LCPR-30 and LCPR-40 had significantly lower strain than the LCPR-20, and plate strain was significantly higher adjacent to the screw closest to the fracture site. For the short working length, there was no significant difference in strain across any LCPR constructs or at any region of the plate. Plate strain was significantly lower for the short working length compared to the long working length for the LCP-Mono and LCPR-20 constructs, but not for the LCPR-30 and LCPR-40 constructs.
Clinical Significance:
The increase in plate strain encountered with a long working length can be overcome by the use of a pin of 30-40% intramedullary diameter. Where placement of a large diameter pin is not possible, screws should be placed as close to the fracture gap as possible to minimize plate strain and distribute it more evenly over the plate.
Related Concept Videos
Normal Strain under Axial Loading
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
Temperature Dependent Deformation
Strain Energy
Consider a rod that is fixed at one end and subjected to an axial force at the free end. This axial force induces stress within the rod, leading to its elongation. As the axial force increases, so does the elongation of the rod, illustrating a direct relationship between the force applied and the resulting...
Deformation of Member under Multiple Loadings
In the case of a member with a variable cross-section, the strain is not constant but depends on the position. The deformation of an...
Plastic Deformation in Circular Shafts

