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Published on: October 1, 2019
On the problems of describing joint axis alignment
Kevin A Ball1, Thomas M Greiner
1Department of Physical Therapy, University of Hartford, West Hartford, CT 06117, USA. keball@hartford.edu
Journal of Biomechanics
|April 24, 2008
Summary
Different methods for describing joint axis alignment lead to significant discrepancies, especially for oblique axes. This study offers algorithms to improve data congruence and facilitate research comparisons.
Area of Science:
- Biomechanics
- Orthopedics
- Kinesiology
Background:
- Three-dimensional joints have oblique axes of rotation.
- Multiple systems exist for describing joint axis alignment, including the plane projection (PP) method and Cardan angles.
- Discrepancies in terminology and methodology hinder data comparison between studies.
Purpose of the Study:
- To explore the implications of incongruence among joint axis expression systems.
- To highlight the extent of differences in joint axis alignment descriptions.
- To provide solutions for accurate data exchange in joint biomechanics research.
Main Methods:
- Comparison of joint axis alignment descriptions using the plane projection (PP) method and Cardan angles.
- Analysis of how obliqueness of the joint axis affects descriptive differences.
- Development of algorithms to standardize joint axis alignment data.
Main Results:
- Discrepancies between PP and Cardan angle descriptions can reach up to 6 degrees for moderate obliqueness.
- Differences increase significantly with greater obliqueness, potentially reaching 75 degrees.
- Existing methods lack congruence, complicating inter-study data comparison.
Conclusions:
- Recognizing the existence and magnitude of incongruence is crucial for researchers.
- Standardized algorithms are needed to alleviate problems in exchanging joint axis alignment data.
- Improved methods will enhance the reliability and comparability of biomechanical research findings.
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