Patient-Specific Bone Contact Segments for Orthopaedic Instrument Fit
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Solution Overview
Problem
Conventional orthopaedic surgical instruments are generic and lack precision, leading to suboptimal fit and accuracy during joint replacement surgeries, as they are not customized to individual patient anatomy.
Innovation Solution
A customized patient-specific surgical instrument with a polymeric body featuring bone-contacting segments that match the patient's bone contours, generated from three-dimensional models based on multiple imaging planes, providing a precise fit and improved surgical guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If generic orthopaedic surgical instruments are used, then device complexity and cost are reduced, but manufacturing precision and fit accuracy deteriorate
Solution Approach 1:
The surgical instrument is divided into multiple discrete bone-contacting segments, each capable of independently contacting different regions of the patient's bone. This segmentation allows each segment to be optimized for specific anatomical regions while maintaining overall instrument functionality, resolving the contradiction between precision fit and device complexity.
Solution Approach 2:
Each bone-contacting segment is designed with specific geometric characteristics tailored to its intended region of contact on the patient's bone. The segments have differentiated shapes, sizes, and contact surface properties matched to local anatomical requirements, enabling high precision fit without requiring the entire instrument to be customized, thus managing complexity effectively.
2Manufacturing precision
If patient-specific customized instruments are used, then manufacturing precision and fit accuracy are improved, but device complexity and production cost increase
Solution Approach 1:
By segmenting the instrument into discrete contact portions, the design simplifies the customization process. Each segment can be independently designed and manufactured based on specific patient anatomy requirements, reducing the overall design complexity compared to a fully customized monolithic instrument while maintaining high precision fit.
Solution Approach 2:
The bone-contacting segments are designed to be interchangeable and can be configured for different patient anatomies using the same basic segment design. This universality allows a single segment type to serve multiple functions across different patients, reducing design complexity and production costs while maintaining patient-specific precision fit.
3Measurement precision
If conventional 2D image slices are used for instrument design, then imaging cost and time are reduced, but measurement precision deteriorates
Solution Approach 1:
Silhouette curves are pre-computed from the 2D image slices during the planning phase, capturing the essential anatomical contours before instrument manufacturing. This preliminary extraction of geometric information allows for accurate instrument design without requiring time-consuming 3D reconstruction processes during surgery, resolving the contradiction between measurement precision and processing time.
Solution Approach 2:
The silhouette curves serve as simplified 2D representations (copies) of the complex 3D bone anatomy, capturing the essential geometric information needed for instrument contact surfaces. This copying approach maintains measurement precision for the critical contact interfaces while significantly reducing the computational and temporal resources required compared to full 3D modeling.
Data Source
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Figure 3A~3B
AI summary
An orthopaedic surgical instrument (10) includes a customized patient-specific surgical instrument having a body. The body has a bone-facing surface (34) and an outer surface positioned opposite the bone-facing surface. The body includes a number of bone-contacting segments (42) raised relative to the bone-facing surface (34). The bone-contacting segment (42) include negative contours shaped to match corresponding positive contours of a patient's bone (12). The positive contours correspond to silhouette curves of a three-dimensional model of the patient's bone that correspond to contours of the patient's bone captured in images used to generate the model. The body further includes a number of surgical guides (78) extending from the outer surface to the bone-contacting surface or the bone-facing surfaces. A method associated with the instrument is also disclosed.