X-ray Calibration Jig with Fiducial Markers for Knee Alignment
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Solution Overview
Problem
Current orthopaedic surgical instruments are generic and lack patient specificity, leading to challenges in accurately aligning and positioning prosthetic joints during joint arthroplasty procedures, requiring surgeons to rely on guesswork and intra-operative decision-making.
Innovation Solution
An x-ray calibration apparatus with a radiolucent knee alignment jig and radio-opaque fiducial markers is used to take precise x-ray images from multiple angles, allowing for registration and calculation of scaling factors and beam angles, enabling the generation of customized patient-specific orthopaedic instruments with accurate alignment and positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If generic orthopaedic surgical instruments are used, then device simplicity and ease of manufacture are improved, but manufacturing precision and alignment accuracy deteriorate
Solution Approach 1:
Patient-specific instruments are manufactured before surgery based on pre-operative imaging data (CT or MRI scans). The instruments incorporate patient-specific anatomical surface contours that are determined and fabricated in advance, allowing precise alignment without requiring complex intra-operative adjustments or guesswork by the surgeon.
Solution Approach 2:
The patient-specific instruments feature localized custom-fit surfaces that match the unique geometry of the individual patient's bone anatomy. These customized contact surfaces are applied only to the specific regions where the instrument interfaces with the patient's bone, while other portions of the instrument may use standardized components.
2Manufacturing precision
If patient-specific orthopaedic instruments are used, then alignment accuracy and positioning precision are improved, but device complexity and manufacturing complexity increase
Solution Approach 1:
The patient-specific instruments are created by making precise digital copies of the patient's actual bone surfaces from imaging data. These digital models are then used to manufacture instruments with matching negative impressions or conformal surfaces that replicate the patient's unique anatomy, ensuring perfect fit without requiring complex adjustment mechanisms.
Solution Approach 2:
All complex customization and planning is performed before surgery using pre-operative imaging and computer modeling. The patient-specific instruments are fabricated in advance with all necessary alignment features built in, eliminating the need for complex intra-operative decision-making or adjustable mechanisms during the surgical procedure.
3Measurement precision
If multiple x-ray images from different angles are taken, then measurement precision and positioning accuracy are improved, but loss of time and procedural complexity increase
Solution Approach 1:
Comprehensive imaging data is collected before surgery to create three-dimensional models of the patient's anatomy. This preliminary action allows all necessary measurements and planning to be completed in advance, eliminating the need for time-consuming intra-operative imaging or repeated x-rays during the surgical procedure.
Solution Approach 2:
The system transitions from two-dimensional x-ray images to three-dimensional digital models of the patient's anatomy. By reconstructing volumetric data from multiple x-ray views or using CT/MRI scanning, the system creates comprehensive 3D representations that provide complete spatial information without requiring multiple separate measurement sessions during surgery.
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 method reduces surgeon guesswork and improves the accuracy of orthopaedic instrument placement, ensuring proper alignment and positioning of prosthetic joints, enhancing the precision and effectiveness of joint arthroplasty procedures.
Implementation Method 1
a first plurality of radio-opaque fiducial markers positioned within the lateral sidewall and a second plurality of radio-opaque fiducial markers positioned within the medial sidewall
Data Source
AI summary
An x-ray calibration apparatus includes a radiolucent knee alignment jig configured to receive a knee of a patient and a radiolucent cushion configured to hold a patient's knee at a fixed angle of flexion. The x-ray calibration apparatus also includes a number of radio-opaque fiducial markers positioned within the radiolucent knee alignment jig.