Rotating Arm Bone Cement Distributor for Uniform Mantle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current techniques for distributing bone cement on the surface of bones, particularly for resurfacing prostheses, face challenges with low viscosity cements, such as limited working time, inadequate fixation, and uneven cement distribution, which can lead to bone necrosis, improper seating of implants, and reduced torsional stability.
Innovation Solution
An instrument with a shaft and rotatable arm is used to control the distribution of bone cement on the bone surface, ensuring uniform penetration and adequate fixation by rotating the arm to sweep and apply pressure on the cement, particularly effective with high viscosity cements that do not flow freely, allowing for better penetration into the porous bone structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If low viscosity bone cement is used, then good penetration of cancellous bone and displacement capability are achieved, but working time is limited and control of pressurisation is difficult
Solution Approach 1:
The patent changes the viscosity parameter of bone cement from low to high viscosity. High viscosity cement provides extended working time (typically 40-60 minutes compared to 20 minutes for low viscosity), while the instrument designed in the patent enables adequate penetration and uniform distribution through mechanical assistance during application.
2Ease of operation
If low viscosity bone cement is used, then cement can be displaced when shell is fitted, but inadequate fixation and poor torsional stability occur
Solution Approach 1:
The patent employs high viscosity bone cement which provides superior fixation strength and torsional stability. The instrument facilitates adequate penetration and uniform distribution of the high viscosity cement, ensuring reliable fixation while maintaining the ability to displace excess cement during shell fitting.
3Reliability
If high viscosity bone cement is used, then working time is extended and fixation is improved, but uniform distribution on bone surface is difficult
Solution Approach 1:
The patent introduces a specialized instrument as an intermediary between the high viscosity bone cement and the bone surface. The instrument includes a distribution mechanism with a surface that contacts the cement and transfers it uniformly to the bone, overcoming the natural tendency of high viscosity cement to resist flow and distribute unevenly.
Solution Approach 2:
The patent replaces reliance on cement flow characteristics (fluid mechanics) with a mechanical distribution system. The instrument uses controlled mechanical motion to spread and distribute the high viscosity cement uniformly, substituting the need for cement to flow freely with an active mechanical transfer mechanism.
4Reliability
If high viscosity bone cement is used, then pressurisation control is improved, but penetration into porous bone structure is reduced
Solution Approach 1:
The instrument acts as an intermediary that applies controlled pressurisation to the high viscosity cement during application. This mechanical assistance enables adequate penetration into the porous bone structure while maintaining the advantages of improved pressurisation control and extended working time associated with high viscosity cement.
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 instrument ensures a uniform and adequate cement mantle on the bone surface, enhancing the fixation and stability of the resurfacing prosthesis, reducing the risk of bone necrosis and foreign particle ingress, while allowing for secure seating and improved resistance to torsional forces.
Implementation Method 1
shaped so as to contact the cement on the bone when the at least one arm is rotated about the shaft axis
Implementation Method 2
The at least one arm is configured to rotate about the shaft axis
Data Source
AI summary
An instrument is provided for controlling the distribution of bone cement on a surface of a prepared bone so as to prepare the bone to receive a resurfacing prosthesis. The instrument includes a shaft having a shaft axis configured to at least partially disposed within the bore of the bone, and at least one arm coupled to the shaft. The at least one arm is configured to rotate about the shaft axis and shaped so as to contact the cement on the bone when the at least one arm is rotated about the shaft axis.