Prosthesis Press-Fit Fixation Quantitative Assessment
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Solution Overview
Problem
Current methods lack a quantitative assessment for press-fit fixation in hip replacement surgery, leading to inadequate initial implant stabilization, which results in complications such as aseptic loosening and fractures, due to the complex bone-implant interface and variability in bone density and surgeon technique.
Innovation Solution
A system and method for quantitatively assessing press-fit fixation by monitoring rigidity and elasticity metrics during the insertion of a prosthesis into a bone cavity, using an invasive sensing mechanism to guide the application of force and prevent excessive stress, allowing for standardized and optimal fixation without relying on surgeon proprioception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oversized prosthesis is impacted into an undersized bone cavity to achieve press-fit fixation, then primary implant stability is improved, but the risk of bone fracture increases due to excessive force application
Solution Approach 1:
The system employs sensors to detect bone density and real-time force feedback during impaction, allowing dynamic adjustment of impact force to achieve optimal press-fit fixation without exceeding bone fracture thresholds. The feedback loop continuously monitors insertion depth, resistance forces, and bone mechanical properties to prevent harmful over-impaction while ensuring adequate initial stability.
Solution Approach 2:
The system changes physical parameters including bone density measurements, impact force magnitude, impaction rate, and prosthesis insertion depth to optimize the press-fit process. By adjusting these parameters based on real-time feedback, the system achieves reliable fixation while adapting to varying bone quality and preventing fracture risks associated with fixed-force impaction methods.
2Ease of operation
If manual mallet-based techniques are used for prosthesis impaction, then surgical simplicity is maintained, but quantitative control and assessment of press-fit fixation quality is lost
Solution Approach 1:
The system replaces manual mallet-based mechanical impaction with a controlled delivery mechanism that provides quantitative force application and real-time feedback. This substitution enables precise measurement of impaction forces, insertion depth, and fixation quality metrics while maintaining the essential impaction function, thereby achieving both operational simplicity and measurement precision.
Solution Approach 2:
The system enables autonomous assessment of press-fit fixation quality through integrated sensors and automated analysis algorithms that evaluate insertion depth, force-feedback characteristics, and bone-implant interface properties. This self-service capability provides quantitative fixation assessment without requiring complex external evaluation procedures, maintaining surgical workflow simplicity while delivering precise measurement data.
3Strength
If screw fixation is used instead of press-fit technique, then immediate mechanical stability is achieved, but risks of neurovascular injury, fretting, metallosis, and osteolysis increase
Solution Approach 1:
The system enables press-fit fixation to achieve mechanical stability equivalent to screw fixation by precisely controlling impaction parameters including force magnitude, application rate, and total energy delivered. Through optimized parameter control and real-time feedback, the system achieves sufficient initial stability without the harmful effects associated with screw fixation, eliminating neurovascular injury risks and preventing fretting, metallosis, and osteolysis.
4Ease of operation
If surgeons rely on qualitative proprioceptive senses to assess press-fit fixation, then real-time assessment during surgery is possible, but quantitative precision and consistency across different surgeons are lost
Solution Approach 1:
The system replaces subjective proprioceptive assessment with objective sensor-based measurement of impaction forces, insertion depth, and fixation characteristics. This substitution provides quantitative precision and eliminates inter-surgeon variability while maintaining real-time assessment capability during the surgical procedure, thereby achieving both operational ease and measurement consistency.
Solution Approach 2:
The system provides real-time feedback through sensors that monitor impaction forces, resistance changes, and insertion depth, delivering quantitative assessment data to the surgeon during the procedure. This feedback mechanism maintains the real-time decision-making advantage of proprioceptive assessment while providing objective, measurable, and consistent data that eliminates subjective variability between different surgeons.
Data Source
AI summary
A system and method for quantitatively assessing a press fit value (and provide a mechanism to evaluate optimal quantitative values) of any implant/bone interface regardless the variables involved including bone site preparation, material properties of bone and implant, implant geometry and coefficient of friction of the implant-bone interface without requiring a visual positional assessment of a depth of insertion. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements.