Hip Implant Registration Using Dynamic Reference Tracking
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Solution Overview
Problem
Current computer-assisted surgery (CAS) systems for total hip arthroplasty lack precision in independently measuring and positioning the femoral and acetabular components relative to a unifying anatomical reference, leading to potential malposition and increased risk of complications such as dislocation and limb length discrepancies.
Innovation Solution
A computer-assisted surgical navigation system that uses independently registered three-dimensional dynamic reference bodies on the pelvis and femur to track the positions of prosthetic hip joint components, including a tracking device with a hemispherical ball that articulates with both the acetabular and femoral components, allowing for precise measurement of leg length and offset before any joint reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional trial and error methods are used for component positioning, then the surgeon can manually adjust implant position, but measurement precision and positioning accuracy deteriorate leading to malposition and complications
Solution Approach 1:
The patent introduces a tracking device with hemispherical ball as an intermediary that articulates with both femoral and acetabular components. This mediator enables the CAS system to independently track both components' positions and orientations relative to a unifying anatomical reference frame, resolving the measurement precision issue without requiring complex direct measurement systems
Solution Approach 2:
The patent replaces manual trial-and-error mechanical adjustment with optical/electromagnetic tracking systems. The CAS system uses registered reference bodies and tracking devices to digitally measure and visualize component positions, substituting the mechanical trial-reduction-adjustment cycle with precision measurement and computer-assisted positioning
2Productivity
If manual distraction and trial reduction are performed, then component position can be adjusted, but surgical time and procedural complexity increase
Solution Approach 1:
The patent performs preliminary registration of anatomical reference frames (pelvis and femur) and component positions using the tracking device before final implantation. This preliminary measurement and visualization of leg length and offset allows the surgeon to plan and execute positioning in a single attempt, eliminating repeated trial reductions and saving surgical time
3Measurement precision
If independent registration of femoral and acetabular components is implemented, then positioning precision improves, but system complexity and measurement difficulty increase
Solution Approach 1:
The tracking device with hemispherical ball serves multiple functions: it articulates with both femoral and acetabular components, provides a unifying reference for measuring both leg length and offset, and enables independent tracking of both components. This universal device simplifies the measurement process while maintaining high precision for both components simultaneously
Data Source
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AI summary
A computer assisted surgical navigation system and method is disclosed for registering the position of prosthetic hip joint components. Elements are applied to the pelvis and femur, generating a three-dimensional array. These two arrays combine to derive a reference point representing the native joint. A tracking device with a pre-determined shape and dimensions that precisely articulate with an acetabular cup component generates a third three-dimensional array. The device has a further shape and dimensions that independently articulate precisely with a neck portion of a femoral component, which represents a prosthetic joint center that is independently registered in the system. The tracking device concurrently registers the three dimensional positions of the femoral and acetabular prosthetic components, along with the prosthetic joint center and the native joint center, respectively enabling alterations in three dimensional location of the leg length and offset prior to reduction of the prosthetic joint.