Dynamic Bone Bridge with Elastic Polymer Cable
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Solution Overview
Problem
Conventional metal bone plates and staples fail to provide controlled compressive force across fractures due to their high modulus of elasticity, leading to stress-shielding and impaired healing, as they are not capable of accommodating bone contraction and expansion during the healing process.
Innovation Solution
An orthopedic bone plate system featuring an elongated structure with fixation points on either side of a fracture, where an elastic polymer microcable is stretched and secured between these points, allowing for controlled contraction and application of compressive force across the fracture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional metal bone plates are used to stabilize fractures, then rigid stabilization is achieved, but stress-shielding occurs and compressive force cannot be maintained during healing
Solution Approach 1:
The patent changes the material parameter from high-modulus metal to low-modulus polymer, enabling the bone plate to undergo elastic deformation and accommodate bone contraction while maintaining stabilization. The polymer material's lower modulus allows it to stretch and contract with the healing bone, preventing stress-shielding and maintaining compressive force across the fracture site.
Solution Approach 2:
The patent transforms the static, rigid bone plate into a dynamic system where the polymer material can elastically deform in response to bone healing processes. The bone plate dynamically adjusts its length and compressive force as the bone contracts and expands during healing, maintaining optimal mechanical conditions for fracture repair.
2Strength
If high-modulus metal materials are used in bone plates, then structural strength is improved, but the ability to apply controlled compressive force is limited
Solution Approach 1:
The patent changes the mechanical parameter of the plate material from high-modulus metal to low-modulus polymer, which fundamentally alters the force-application characteristics. The polymer's lower stiffness allows it to elastically deform under load, enabling controlled compression across the fracture while maintaining sufficient strength for stabilization.
3Strength
If conventional static bone plates are used, then initial stabilization is achieved, but compressive load cannot be maintained during healing
Solution Approach 1:
The patent transforms the static bone plate into a dynamic system where the polymer material continuously maintains compressive force through elastic deformation. As the bone heals and changes dimension, the polymer plate dynamically adjusts its length and force output, ensuring sustained compression throughout the entire healing process rather than just initially.
Solution Approach 2:
The patent ensures continuous compressive force application through the elastic properties of the polymer material. The bone plate continuously exerts compressive force on the fracture site throughout the healing process, adapting its force output as the bone heals, rather than providing only initial compression that is lost when the bone contracts.
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
The system applies a controlled compressive force to promote healing by accommodating bone contraction and expansion, reducing stress-shielding and enhancing the stability of the fracture during the healing process.
Implementation Method 1
An elastic, polymer cable or microcable is longitudinally stretched and coupled in tension to the elongated structure between the points of fixation, capable of causing the structure to contract in the longitudinal direction
Data Source
AI summary
An orthopedic bone bridge, suitable for internally fixating and stabilizing fractured bones. The bone bridge includes: first and second bone plates for attachment to bone fragments by bone screws or the like on opposite sides of a bone fracture, a pair elongate parallel hollow legs on which the plates are mounted and the second plate is slidably engaged and is moveable with respect to the first plate, and an elastic cable or microcable attached to the first plate and extending down through the legs and around said second plate. The elastic cable is configured to provide a controlled tensile force between the plates when they are pulled into a longitudinally spaced apart position with the bone bridge then applying a correspondingly compressive force onto the bone fracture when the plates are secured to bone fragments on opposite sides of a bone fracture.