Patient-Specific Acetabular Guide with Alignment Arms
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Solution Overview
Problem
Conventional patient-specific acetabular guides face challenges in accurate positioning due to the hemispherical shape of the acetabulum, leading to potential malposition during manual placement in hip-joint replacement surgery.
Innovation Solution
A patient-specific acetabular guide with a cup body having a hemispherical shape, spaced alignment arms, a supporting leg, and a guiding element with a predetermined alignment axis, allowing for secure positioning and orientation using Kirschner pins and custom-made surfaces to match the acetabular and periacetabular surfaces, facilitating guided reaming and implantation procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional patient-specific acetabular guide with a hemispherical cup body is manually placed on the acetabulum, then the guide can be positioned on the acetabular surface, but the hemispherical shape causes difficulty in achieving accurate positioning and orientation, leading to potential malposition
Solution Approach 1:
The acetabular guide is divided into multiple functional components: a cup body for general positioning, alignment arms with contacting portions for precise orientation, and a supporting leg for stability. This segmentation allows each component to perform its specific function, with the alignment arms providing the critical precise positioning that compensates for the limitations of manual placement of the hemispherical cup body.
Solution Approach 2:
The alignment arms act as intermediary elements between the cup body and the acetabulum. These arms with their contacting portions engage with specific periacetabular surfaces to mediate and refine the positioning, transforming the imprecise manual placement of the hemispherical cup into accurate final positioning through the intermediary alignment mechanism.
2Shape
If the cup body is designed with a hemispherical shape to match the acetabulum, then the guide can conform to the acetabular surface, but this shape alone is insufficient to ensure accurate alignment and orientation during manual placement
Solution Approach 1:
The guide structure is segmented into the hemispherical cup body that provides general conformity to the acetabulum, and separate alignment arms with contacting portions that provide precise alignment. This segmentation allows the cup body to maintain its conforming hemispherical shape while the alignment arms independently provide the necessary manufacturing precision for accurate positioning.
Solution Approach 2:
The alignment arms are designed with asymmetric contacting portions that engage with specific asymmetric periacetabular surfaces. This asymmetry ensures that only the correctly oriented guide can be properly positioned, as the contacting portions will only align with their complementary surfaces when the guide is in the correct orientation, thereby ensuring alignment precision beyond what the symmetric hemispherical cup body alone can provide.
Data Source
AI summary
A patient-specific acetabular guide comprises a cup body, a plurality of alignment arms extending from the cup body and engaging periacetabular areas of a pelvis, and a supporting leg protruding from the cup body and abutting against a portion of an acetabular fossa. Each alignment arm has a fixing hole extending inclinedly therethrough to allow a Kirschner pin to pass through and enter the periacetabluar area of the pelvis for positing and orienting the acetabular guide on a predetermined location of an acetabulum.