Offset Implant Extractor for Anterior Hip Surgery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current anterior hip stem implant extractors face challenges in accessing the implant due to anatomical limitations, requiring leg dislocation and bending, which complicates the surgical procedure and recovery, especially when compared to the posterior-lateral approach.
Innovation Solution
The implant extractor features a telescoping push rod with an adjustable length, a support arm, and a jaw assembly with a rocker arm and cam lock mechanism, allowing for flexible positioning and high clamping forces to securely grip and remove hip stem implants, even in the direct anterior approach where space is limited.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional extractor tool is used in the direct anterior approach, then the tool can clear the patient's body, but the patient's leg must be dislocated and bent posterior which complicates the surgical procedure
Solution Approach 1:
The extractor tool is designed with an offset longitudinal axis relative to the implant axis, creating a lateral offset that allows the tool to clear the patient's body without requiring extreme leg positioning. This dimensional change in the tool's geometry resolves the contradiction by enabling anterior approach access while maintaining simple patient positioning.
2Adaptability or versatility
If the patient's leg is positioned to clear the belly, then the extractor can access the implant, but the positioning is limited by the patient's anatomy
Solution Approach 1:
The tool incorporates an adjustable telescoping push rod with variable length, allowing the operator to adjust the tool's reach and positioning parameters to match different patient anatomies. This parameter adjustment enables the tool to access implants in various anatomical configurations without being constrained by fixed geometric limitations.
3Adaptability or versatility
If a telescoping push rod with adjustable length is used, then the tool can navigate around patient anatomy, but the device complexity increases
Solution Approach 1:
The telescoping push rod provides dynamic adjustability, allowing the tool length to be modified during the surgical procedure to accommodate different patient anatomies and implant positions. This dynamic capability is achieved through a cam-locked telescoping mechanism that allows quick adjustment without complex controls.
4Strength
If high clamping forces are applied to securely grip the implant, then the implant can be extracted, but moment forces on the hip increase
Solution Approach 1:
The lateral offset of the tool's longitudinal axis from the implant axis creates a geometric configuration that reduces the moment arm and associated moment forces on the hip joint during extraction. This dimensional offset allows high clamping forces to be applied to the implant while minimizing the reactive moment forces transmitted to the hip.
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 design enables efficient extraction of hip stem implants with reduced moment forces on the hip, facilitating easier surgery and faster recovery by allowing the extractor to navigate around the patient's anatomy, particularly in the direct anterior approach, and providing high clamping forces to securely engage the implant.
Implementation Method 1
a cam lock operatively engaged with the telescoping push rod. According to another aspect, the cam lock includes a cam housed within the shaft body, and a lever extending from the cam
Implementation Method 2
a rocker arm operatively engaged with the telescoping push rod and the jaw
Data Source
AI summary
An implant extractor including a shaft body and a telescoping push rod extending from the shaft body. An adjustor is engaged with the telescoping push rod for adjusting a length of the telescoping push rod. A support arm extends laterally away from the shaft body and a jaw assembly extends from the support arm. The jaw assembly includes a jaw moveable between a locking position and an unlocking position, and a rocker arm operatively engaged with the telescoping push rod and the jaw. The implant extractor provides a line of force spaced from and substantially parallel to an implant to be extracted. As a consequence, there is substantial clearance for an extension handle such as a C-frame or the like which is oftentimes needed to dislodge the implant from surrounding bone. In addition, the implant extractor is capable of gripping a wide range of sizes of hip stem implant trunnions.