Defense Date


Document Type


Degree Name

Master of Science


Biomedical Engineering

First Advisor

Gerald E. Miller

Second Advisor

Peter E. Pidcoe

Third Advisor

Jennifer S. Wayne


The purpose of this study was to build a helical axis algorithm capable of detecting changes in the helical axis intersection of the tibia and femur in human knees. This algorithm was designed and tested using three models: a multiplanar rigid body model, a mathematical model, and a cylinder model. The multiplanar rigid body model closely mimics knee movement without supporting ligamentous structures, thus the movement was unconstrained. In this model kinematic position data were collected using both MotionMonitor™ (MotionMonitor™ Version 7.7, Innovative Sports Training, Chicago, IL) and Vicon Nexus 1.3 software system (Oxford Metrics Group, Oxford, UK). To test the algorithm under more controlled conditions and eliminate kinematic collection errors, a mathematical model was used. The cylinder model was used to obtain constrained movement data using MotionMonitor™. The results from the two models using a kinematic collection system were inconclusive due to the large errors in the collection process. The mathematical model validated the helical axis algorithm. Statistical analysis of kinematic data showed good correlation between the data but the errors from this data were to large to be useful in a clinical setting. Further research is needed to use the helical axis to model the tibial and femoral rotation on the meniscus.


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VCU Theses and Dissertations

Date of Submission

July 2009