Ultrasonic Bone Preparation for Hip Prosthesis Alignment
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Solution Overview
Problem
Current methods for prosthesis installation, particularly in hip replacement surgery, face challenges with inconsistent acetabular cup placement due to unpredictable torques and moment arms from manual mallet use, leading to issues like hip instability, polyethylene wear, and the need for revision surgery.
Innovation Solution
The introduction of a system and method utilizing axial alignment of force transference through a sliding hammer with stops to impart non-torqueing forces, combined with ultrasonic vibrations to enhance bone preparation and implantation, allowing for precise alignment and reduced trauma during prosthesis installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual mallet is used for prosthesis installation, then the prosthesis can be inserted into bone, but unpredictable torques and moment arms cause inconsistent acetabular cup placement and mal-alignment
Solution Approach 1:
The patent replaces the manual mallet system with an ultrasonic bone preparation system that uses ultrasonic vibrations to prepare the bone and facilitates prosthesis insertion. The ultrasonic device eliminates unpredictable torques by providing controlled, standardized insertion forces through mechanical guidance and resonance-based bone preparation.
Solution Approach 2:
The patent changes the physical parameters of bone preparation by using ultrasonic vibrations at specific frequencies that match bone's natural resonance frequencies. This transforms the insertion process from a brute-force mechanical impact to a controlled vibratory process, ensuring consistent and predictable prosthesis placement.
2Productivity
If brute force bone preparation is used, then the prosthesis can be inserted, but bone preparation trauma is increased
Solution Approach 1:
The patent applies ultrasonic mechanical vibrations to the bone preparation process. The ultrasonic device vibrates the bone at high frequencies, which facilitates bone preparation and prosthesis insertion with minimal trauma. The vibratory energy breaks down bone material more efficiently and gently than brute force methods.
Solution Approach 2:
The patent utilizes the transition of bone material response under ultrasonic vibration, where bone undergoes micro-fracturing and remodelling through resonant vibration rather than macro-fracturing from impact forces. This phase-like transition in bone preparation reduces trauma while maintaining insertion efficiency.
3Strength
If mallet force is applied to insert prosthesis, then the prosthesis can be secured, but the amount of force is non-standardized and uncontrolled
Solution Approach 1:
The patent replaces uncontrolled manual mallet force with a standardized ultrasonic vibration system. The ultrasonic device delivers precisely controlled vibratory forces at standardized amplitudes and frequencies, ensuring consistent prosthesis fixation strength without the variability of manual force application.
Solution Approach 2:
The ultrasonic bone preparation system incorporates feedback mechanisms that monitor and adjust the vibratory forces applied to the bone. This feedback control ensures that the insertion force remains within standardized parameters, providing consistent fixation strength while preventing excessive force application.
4Ease of manufacture
If discrete blows from mallet are used, then the prosthesis can be impacted, but undesirable torques and moment arms are produced
Solution Approach 1:
The patent replaces the discrete blow mechanism with a continuous ultrasonic vibration process. The ultrasonic device maintains constant contact with the bone, providing continuous preparatory vibration that eliminates the torque-producing discrete impacts while maintaining insertion simplicity through automated guidance.
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 approach improves the accuracy and consistency of prosthesis placement, reducing the risk of complications such as hip instability and polyethylene wear, while minimizing the force required for insertion and aligning the implant with the bone's natural resonance frequencies.
Implementation Method 1
a motive system, coupled to the cutting implement, configured to operate the cutting implement in the primary mode of freedom of motion and in a secondary mode of primary mode of freedom different from the primary mode of freedom wherein the secondary mode of freedom includes an ultrasonic vibratory motion
Implementation Method 2
possibly, engaging bone's natural resonance frequencies (modal frequencies) which may make bone bend and flex
Implementation Method 3
Vibrations may affect interaction of the bone preparation implement and/or oversized implant with bone by two phenomena: (i) changing the frictional interactions between bone and metal
Data Source
AI summary
A system and method for improving installation of a prosthesis. Devices include prosthesis installation tools, prosthesis assembly tools, site preparation systems, and improved power tools used in implant site preparation, the tools including a secondary motion that preferably includes an ultrasonic vibration.