Dynamic Intramedullary Nail with Telescoping Bias Mechanism
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Solution Overview
Problem
Current intramedullary nails struggle to balance stabilization and motion at the fracture site, as excessive motion can hinder complete bone healing while inadequate motion may impede the healing process.
Innovation Solution
An intramedullary nail design featuring a telescoping arrangement with a bias member, such as a spring or compliant membrane, allowing controlled motion along the longitudinal axis, combined with an alignment assembly and a biocompatible surface material like zinc to enhance healing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an intramedullary nail is designed with rigid fixation to stabilize the fractured bone, then the stabilization and alignment are improved, but the motion at the fracture site is excessive restricted which may impede the healing process
Solution Approach 1:
The intramedullary nail incorporates a dynamic telescoping arrangement between the proximal and distal portions, allowing controlled longitudinal motion while maintaining lateral stability. The bias member (spring or compliant membrane) enables the nail to adapt its stiffness, providing rigid fixation when needed and allowing controlled motion to stimulate bone healing during the recovery process.
2Productivity
If an intramedullary nail allows motion at the fracture site to enhance healing, then the bone remodeling is improved, but the stabilization and alignment may be compromised
Solution Approach 1:
The intramedullary nail is divided into distinct proximal and distal portions that can move independently along the longitudinal axis through the telescoping arrangement. This segmentation allows the nail to provide stability at the fracture site while permitting controlled motion to stimulate bone healing, effectively separating the functions of stabilization and healing promotion.
3Stability of the object's composition
If a static construct with locking screws is used to ensure rotational stability, then the rotational control is improved, but the controlled longitudinal motion is restricted
Solution Approach 1:
The nail employs dynamic locking mechanisms that allow longitudinal telescoping motion between proximal and distal portions while maintaining rotational stability through the bias member. The spring or compliant membrane provides continuous rotational constraint while permitting controlled longitudinal displacement, achieving both rotational stability and longitudinal motion capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design provides adequate stabilization while allowing controlled motion to promote bone healing, reducing the risk of incomplete healing and enhancing the bone remodeling process.
Implementation Method 1
a bias member or device disposed between the distal and proximal portions for biasing the distal and proximal portions apart along a longitudinal axis
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3A~3B
AI summary
An intramedullary nail for fixation and stabilization of a fractured bone that also allows for a controlled amount of longitudinal motion at the fracture site to encourage bone remodeling and healing is described. The intramedullary nail has a proximal portion and a distal portion that are coupled together in a manner by a biasing assembly that provides for a controlled movement of the proximal and distal portions relative to each other so that when a patient puts pressure on the bone, such as when walking, the fracture site compresses and the bone ends move together, and when the pressure is released from the bone, the bone ends are biased apart by a controlled amount.