Injectable Bone Cement with Linoleic Acid Modifier
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Solution Overview
Problem
Current bone cements, such as PMMA, have a high Young's modulus that can negatively affect adjacent tissues and are not adaptable to individual patient needs, particularly in osteoporotic patients, and existing methods for reducing modulus or incorporating drugs are either ineffective or unsuitable for in vivo applications.
Innovation Solution
An injectable bone cement composition comprising a dry powder component, a liquid component, and a modifier like linoleic acid or its derivatives, which is added to the liquid component in concentrations of 0.1 to 12 v/v to modify the Young's modulus and facilitate drug release, allowing for a tunable mechanical properties and controlled drug delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PMMA bone cement is used to repair and augment spinal compression fractures and fixate hip and knee implants, then the mechanical strength and fixation capability are improved, but the high Young's modulus negatively affects the biomechanics and promotes fractures in adjacent tissues
Solution Approach 1:
The patent modifies the Young's modulus of PMMA bone cement by changing chemical composition parameters, specifically incorporating flexible species with relatively long chains (such as polyethylene glycol chains of 200-2000 Daltons) that act as spacers between polymer chains, lowering the glass transition temperature and reducing the Young's modulus to better match adjacent bone tissue
Solution Approach 2:
The patent creates a composite material system by combining PMMA with plasticizers or copolymerizing with flexible monomers, resulting in a composite cement material that maintains structural integrity while reducing stiffness to prevent stress shielding and adjacent tissue fractures
2Adaptability or versatility
If the Young's modulus is reduced by chemical composition changes to adapt to patient-specific needs, then the adaptability to patient conditions is improved, but the material complexity and formulation difficulty increase
Solution Approach 1:
The patent enables patient-specific adaptation by systematically varying the concentration of plasticizers or flexible monomer content in the cement formulation, allowing the Young's modulus to be tuned to match the mechanical properties of adjacent bone tissue in osteoporotic or normal patients
Solution Approach 2:
The patent allows for localized modification of cement properties by controlling the distribution and concentration of plasticizing agents in specific regions or formulations tailored to the patient's bone quality, creating locally optimized mechanical properties
3Object-affected harmful factors
If porosity is induced in the material to reduce Young's modulus and allow bone ingrowth, then the biocompatibility and bone integration are improved, but the structural strength and integrity may be compromised
Solution Approach 1:
The patent incorporates porosity into the PMMA bone cement structure to enable bone ingrowth and improve biocompatibility, while carefully controlling pore size, distribution, and volume fraction to maintain adequate structural strength for load-bearing applications
4Adaptability or versatility
If drugs are directly mixed into the PMMA powder for incorporation into the cement, then the drug delivery capability is improved, but the control over drug release is limited and depends on relative surface area
Solution Approach 1:
The patent utilizes the porous structure of the bone cement as drug reservoirs, allowing drugs to be loaded into the pores and released through diffusion and erosion mechanisms, providing controlled and sustained drug delivery independent of surface area considerations
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 composition effectively reduces the Young's modulus of the bone cement to match surrounding bone tissue, promoting osseointegration and controlled drug release without significantly affecting cell viability, making it suitable for various medical applications.
Implementation Method 1
Large molecules, may also act as physical spacers/plasticizers, if not grafted to the main polymer chain or network. The addition of plasticizers would also result in a lower Young's modulus.
Implementation Method 2
Another simple approach in order to decrease the modulus of PMMA bone cements may be their chemical modification, namely, copolymerization or grafting with somewhat more flexible species containing relatively long chains.
Implementation Method 3
A porous structure may help to control the release of previously mentioned drugs or other types of growth factors from the material.
Implementation Method 4
The introduction of drugs into bone cements is of great importance in order to help the patients to recover upon surgery and to obtain the maximum benefit out of the cement.
Data Source
AI summary
The embodiments relate to an injectable composition for a bone cement material comprising a dry powder component, a liquid component and a modifier configured to modify a Young's modulus of the bone cement material. The modifier is linoleic acid or a derivative thereof and is present in a concentration of 0.1 to 12 v/v of the liquid component.