A novel way to dynamize a spatial frame and optimize fracture healing
Christopher A Iobst1, Edward Milne2, Anthony Khoury3
1Nationwide Children's Hospital, 700 Children's Drive, Suite T2E-A2700, Columbus, OH, United States.
Injury
|October 11, 2020
Summary
Modified shoulder bolts allow controlled dynamization of spatial frames, enhancing fracture healing by increasing beneficial dilatational strains without harmful shear motion. This innovation optimizes bone repair in external fixation.
Area of Science:
- Orthopedics
- Biomechanical Engineering
- Bone Healing Research
Background:
- Fracture site motion influences bone healing through mechanical strains.
- Axial micro-motion promotes healing via dilatational strains, while shear motion impedes it.
- Dynamization of external fixation (Ilizarov, Spatial Frame) aims to improve bone healing by increasing mechanical stress.
Purpose of the Study:
- To assess the effect of modified shoulder bolts on spatial frame dynamization.
- To evaluate how these modifications influence fracture site motion during dynamic loading.
Main Methods:
- Constructed five identical two-ring spatial frames on Sawbones tibias with osteotomies.
- Applied sinusoidal loads at 0.25 Hz, recording axial force, displacement, and segment motion.
- Tested eight configurations, including rigid frames, frames with loosened struts, and frames with dynamization bolts.
Main Results:
- No significant difference in vertical displacement between locked frames and the Ilizarov frame.
- Modified shoulder bolts increased vertical movement by an average of 1.83 mm.
- Significant shear forces were observed when unlocking single or multiple struts, but not with modified shoulder bolts.
Conclusions:
- Modified shoulder bolts can be effectively used for spatial frame dynamization.
- This method allows for controlled dynamization without increasing detrimental shear motion at the fracture site.
Related Concept Videos
01:27Fractures: Bone Repair
4.5K
Treatment for a fracture is based on the type of break, the bone affected, and the patient's age.
Minor fractures with no bone displacement are treated by immobilizing the fractured bone using a cast or splint. However, in the case of fractures with displaced bones, the broken bones are repositioned before immobilization to ensure successful healing without deformation and loss of function. The realignment of fractured bone ends is performed through a process called reduction. If the...
Minor fractures with no bone displacement are treated by immobilizing the fractured bone using a cast or splint. However, in the case of fractures with displaced bones, the broken bones are repositioned before immobilization to ensure successful healing without deformation and loss of function. The realignment of fractured bone ends is performed through a process called reduction. If the...
4.5K
01:40Bone Remodeling
39.8K
Bone remodeling is a continuous and balanced process of bone resorption by osteoclasts and bone formation by osteoblasts. In adults, it helps maintain bone mass and calcium homeostasis. While mechanical stress can stimulate turnover as part of the normal maintenance and reparative process, several hormones also regulate bone remodeling.
39.8K