Ankle Replacement Alignment Arm for Precise Pin Placement
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Solution Overview
Problem
Existing implant alignment systems for joint deformities, such as in ankle replacement surgeries, often fail to accurately align implants with the mechanical axis of the extremity, leading to potential misplacement of bone screws and suboptimal surgical outcomes.
Innovation Solution
The development of a joint-line referencing system comprising an alignment arm with pin tube holes, a pin tube guide member, and an alignment foot with a handle, allowing for precise alignment and secure pin insertion into bones, along with optional angelwing alignment members for assessing tibial slope and varus-valgus alignment, facilitating accurate implant positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional alignment guides are attached via pins or k-wires, then the alignment system can be secured to the patient's foot and tibia, but the accuracy of implant alignment with the mechanical axis deteriorates leading to potential misplacement of bone screws
Solution Approach 1:
The alignment arm serves as an intermediary component that connects the alignment foot (attached to the patient's foot) with the reference line system. This intermediary structure allows for precise alignment reference while maintaining secure attachment, thereby improving both measurement precision and reliability of bone screw placement without the drawbacks of traditional direct pin attachment methods
2Manufacturing precision
If alignment systems use multiple components (alignment arm, pin tube guide, angelwing members), then the precision of implant positioning is improved, but the device complexity increases
Solution Approach 1:
The alignment system merges multiple functions into integrated components. The alignment arm combines attachment functionality with alignment reference capabilities, while the pin tube guide member integrates positioning and guidance functions. The angelwing alignment member combines slope assessment and varus-valgus alignment functions in a single component, thereby achieving high manufacturing precision while managing device complexity through functional integration
3Ease of operation
If the alignment foot includes a handle and shim, then the ease of positioning and orienting the alignment arm is improved, but the device complexity increases
Solution Approach 1:
The alignment foot with handle and shim enables self-service positioning by the surgeon. The handle provides direct manual control for positioning, while the shim allows for easy adjustment and orientation of the alignment arm relative to the patient's anatomy. These features improve ease of operation by allowing the surgeon to directly manipulate and adjust the alignment system without requiring additional tools or complex mechanisms
Data Source
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AI summary
Alignment instruments may include joint-line referencing systems having an alignment arm having a body with first and second portions defining first and second sides. The first portion has at least one first pin tube through-hole extending from the first to the second side. The second portion has a first opening on the first side. A pin tube guide member is receivable in the first through-hole. The pin tube guide member has a passageway therethrough. An angelwing alignment member includes a portion receivable in the first opening of the alignment arm. An alignment foot is secured to the second portion, and the alignment foot has a handle and a shim. The shim is positionable in a joint between a first bone and a second bone, the alignment arm is alignable relative to a first bone, and the pin tube guide is operable for securing a pin into the first bone