Hip Impactor Device Precision Shock Delivery
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Solution Overview
Problem
Existing impactor devices for inserting ceramic inserts into hip cups are imprecise, often resulting in off-axis or incomplete insertions due to incorrect force and orientation, leading to repeated attempts or damaged prostheses.
Innovation Solution
A precision impactor device that ensures a controlled shock is applied along the correct axis with the right force by coupling the rod to a ceramic insert, featuring a slide mechanism with a spring constraint and latching means to guarantee precise alignment and energy transfer, preventing erroneous impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hammer impactor device is used to apply shock to the rod, then the insertion process can be performed, but the force applied is imprecise and often neither of the correct value nor perfectly centered, resulting in misaligned and/or incomplete insertion
Solution Approach 1:
The rod is pre-loaded into the barrel of the impactor device before the impact is delivered. This preliminary positioning ensures that the rod is correctly aligned and secured in place, so that when the hammer strikes, the force is applied precisely along the intended axis. The pre-loading mechanism includes positioning features that guide the rod into the correct position and prevent lateral movement during impact.
Solution Approach 2:
The barrel acts as an intermediary between the hammer and the rod. It transmits the impact force from the hammer to the rod while maintaining precise alignment. The barrel's internal geometry and positioning features ensure that the force is applied centrally and along the correct axis, eliminating the imprecision that would occur with direct hammer-to-rod contact.
2Reliability
If the impact force is increased to ensure complete insertion, then insertion completeness improves, but the impact can be too strong causing a crack in the insert and/or cup
Solution Approach 1:
The device allows for controlled variation of impact parameters including force magnitude, direction, and number of strikes. The barrel's design and positioning features enable precise control of these parameters, allowing the surgeon to deliver sufficient force for complete insertion while preventing excessive force that would cause cracking. The geometry of the barrel and rod interface ensures force is applied within safe limits.
3Stability of the object's composition
If the rod is integrated with the device body, then structural stability is improved, but cleaning the system becomes difficult
Solution Approach 1:
The rod is designed as a separate, removable component from the barrel and hammer assembly. This segmentation allows the rod to be easily detached for cleaning or replacement, while the barrel and hammer remain as the permanent device body. The rod can be removed from the barrel's distal end, providing excellent access for cleaning both the rod and the internal surfaces of the barrel.
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 device significantly reduces the number of faulty insertions and prosthesis damage by ensuring precise alignment and force application, facilitating easy use and cleaning with an independent rod design.
Implementation Method 1
an impactor device in the form of a hammer (10) mounted under the load of a spring (11)
Implementation Method 2
the surgeon applies a shock to the rod to drive the insert into the cup
Implementation Method 3
The slide can be mounted under the tension of a spring tending to maintain the distal end of the slide away from the distal opening of the barrel
Data Source
Figure 1~2
Figure 3A~3B
Figure 4a~5b
AI summary
Impactor device (1) for delivering a shock to a stem, the stem itself being coupled to an insert-forming element for insertion into a receiving element, in particular a ceramic insert in a cup of a hip acetabular cavity; the impactor device (1) comprising - a barrel-forming element (4) defining a channel (5) or inner chamber having an opening through which at least a portion of the stem can be inserted, in particular a proximal end section of the stem; - shock application means for applying to the portion of the stem inserted into the chamber a shock of predetermined power; and - means (12, 14) for triggering the shock application means.