3D Lower Limb Alignment Measurement for Hip Version and Tibial Torsion
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Solution Overview
Problem
Current methods for measuring lower limb alignment, particularly in the coronal, sagittal, and axial planes, lack accuracy and reliability, leading to inadequate correction of misalignments and increased risk of musculoskeletal pathologies such as joint deterioration and discomfort.
Innovation Solution
A method involving a three-dimensional scan of the lower limb to identify axes of symmetry for hip version and tibial torsion, using reference points and angles between these axes to determine alignment, which can be displayed and compared to predetermined levels, allowing for precise measurement and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three-dimensional scanning and axis of symmetry identification methods are used, then measurement precision of hip version and tibial torsion is improved, but device complexity and measurement time increase
Solution Approach 1:
The patent transitions from traditional two-dimensional radiographic measurements to three-dimensional scanning and visualization. By reconstructing the lower limb in 3D space and identifying axes of symmetry in multiple planes (coronal, sagittal, axial), the system achieves superior measurement precision for hip version and tibial torsion while providing comprehensive spatial understanding that 2D methods cannot provide.
Solution Approach 2:
The patent introduces computer-based image processing and three-dimensional reconstruction algorithms as intermediaries between the scanning device and the final measurement. These computational tools automatically identify axes of symmetry, calculate alignment angles, and generate visual representations, thereby managing the complexity of 3D measurements while delivering precise results.
2Measurement precision
If three-dimensional scanning and axis of symmetry identification methods are used, then measurement precision of hip version and tibial torsion is improved, but measurement time increases
Solution Approach 1:
The patent performs three-dimensional reconstruction and axis identification computations in advance, storing the processed data and calculated alignment measurements for future reference. This preliminary processing allows rapid retrieval and comparison of measurements without repeating the entire 3D analysis procedure, thereby reducing measurement time while maintaining high precision.
Solution Approach 2:
The patent creates digital three-dimensional copies and models of the patient's lower limb anatomy from scanning data. These digital replicas can be repeatedly analyzed, measured, and compared without requiring additional physical scanning or patient positioning, significantly reducing measurement time while preserving measurement precision across multiple assessments.
3Ease of operation
If traditional two-dimensional radiographs are used for HKA measurement, then ease of operation is improved, but measurement precision of axial plane alignment is worsened
Solution Approach 1:
The patent explicitly addresses the limitation of two-dimensional radiographs in measuring axial plane alignment by implementing three-dimensional scanning and visualization. The 3D approach enables accurate measurement of hip version and tibial torsion in the axial plane, which cannot be adequately assessed with conventional 2D HKA measurements, thereby improving measurement precision without significantly compromising ease of operation through automated processing.
Data Source
AI summary
A method of determining axial alignment of a lower limb includes determining a three-dimensional volume based on a scan of a lower limb of a patient, identifying a level of hip version by referring to a first axis of symmetry of a femoral neck and a second axis of symmetry of a distal portion of a femur, wherein hip version is defined by an angle between the first axis of symmetry and the second the second axis of symmetry, identifying a level of tibial torsion by referring to a third axis of symmetry of a proximal portion of a tibia and a fourth axis of symmetry of a distal portion of the tibia, wherein tibial torsion is defined by an angle between the third axis of symmetry and the fourth axis of symmetry, and providing the level of hip version and the level of tibial torsion to a user.