Surgical Assembly Tool for Hip Implant Taper Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for assembling the head to the stem in hip replacement surgeries lack an efficient and reliable instrument to securely attach the components, leading to potential micromotion issues and complications during the procedure.
Innovation Solution
A surgical assembly tool with a frame and force applier is used to apply a controlled quasistatic axial force along the taper axis, ensuring secure attachment of the head to the stem while minimizing axial force transmission to the femur, utilizing a screw mechanism and adjustable components for precise alignment and retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional assembly method is used to attach the head to the stem, then the assembly process is simple, but micromotion occurs between the components leading to assembly failure
Solution Approach 1:
The assembly tool is divided into distinct functional segments: a frame structure for positioning, a force applier mechanism for applying controlled force, and a retaining member for securing components. This segmentation allows each part to perform its specific function optimally while maintaining overall tool reliability for micromotion-free assembly.
Solution Approach 2:
The assembly tool acts as an intermediary device between the surgeon and the implant components. It mediates the assembly process by providing controlled force application and precise positioning, ensuring reliable head-to-stem attachment without micromotion while the surgeon operates the tool.
2Strength
If excessive force is applied to assemble the head to the stem, then secure attachment is achieved, but axial force is transmitted to the femur causing damage
Solution Approach 1:
The force applier mechanism is designed to concentrate and apply force locally at the head-stem interface where assembly is needed. The retaining member and frame structure ensure that force is applied precisely where required without propagating to the femur, achieving strong joint attachment while preventing harmful force transmission to bone.
Solution Approach 2:
The assembly tool serves as an intermediary that isolates the high assembly forces from the femur. The tool's frame and retaining member structure absorb and contain the forces during assembly, allowing secure head-to-stem attachment while protecting the femur from damaging axial force transmission.
3Manufacturing precision
If manual assembly is performed without a specialized tool, then the procedure is faster, but precise alignment and controlled force application cannot be achieved
Solution Approach 1:
The frame structure and retaining member are designed to pre-establish precise alignment between the head and stem components before force application begins. This preliminary positioning ensures accurate alignment is achieved automatically when the tool is engaged, eliminating the need for time-consuming manual alignment adjustments.
Solution Approach 2:
The force applier mechanism provides dynamically controlled force application, allowing the surgeon to apply force gradually and adjust as needed during assembly. This controlled dynamic force application achieves precise alignment and secure attachment efficiently, balancing precision requirements with procedural time.
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 tool enables reliable and controlled assembly of the head to the stem, reducing the risk of micromotion and facilitating a secure joint, thus enhancing the stability and success of the hip replacement procedure.
Implementation Method 1
The force applier may be a screw with an actuator coupled to the screw
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An instrument for assembling an implant on a neck. The implant and neck being coupled via a taper having a taper axis. The instrument includes a frame having a distal portion and a proximal portion, the distal portion of the frame including a retaining member adapted to engage a portion of the neck and a connector adapted to engage a corresponding feature of the stem. The instrument also includes a force applier retained in the proximal portion of the frame. The force applier includes a screw having a screw axis that is coaxial with the taper axis, wherein the screw is adapted to engage the implant. As the screw is turned, the force applier applies a force on the implant while the neck is held in place by the frame, thereby causing the tapers of the implant and neck to engage.