Recognizing knee pathologies by classifying instantaneous screws of the six degrees-of-freedom knee motion

Alon Wolf and Amir Degani
Medical and Biological Engineering and Computing, Vol. 45, No. 5, May, 2007, pp. 475-482.


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Abstract
We address the problem of knee pathology assessment by using screw theory to describe the knee motion and by using the screw representation of the motion as an input to a machine learning classifier. The flexions of knees with different pathologies are tracked using an optical tracking system. The instantaneous screw parameters which describe the transformation of the tibia with respect to the femur in each two successive observation is represented as the instantaneous screw axis of the motion given in its Pl?ker line coordinates along with its corresponding pitch. The set of instantaneous screw parameters associated with a particular knee with a given pathology is then identified and clustered in R^6 to form a ?ignature?of the motion for the given pathology. Sawbones model and two cadaver knees with different pathologies were tracked, and the resulting screws were used to train a classifier system. The system was then tested successfully with new, never-trained-before data. The classifier demonstrated a very high success rate in identifying the knee pathology.

Keywords
Knee kinematics, Screw axis, Pathology classification, Support vector machines

Notes
Grant ID: Berlin / Heidelberg
Associated Center(s) / Consortia: Center for the Foundations of Robotics
Associated Lab(s) / Group(s): Biorobotics and Biomedical Robotics Lab
Number of pages: 8

Text Reference
Alon Wolf and Amir Degani, "Recognizing knee pathologies by classifying instantaneous screws of the six degrees-of-freedom knee motion," Medical and Biological Engineering and Computing, Vol. 45, No. 5, May, 2007, pp. 475-482.

BibTeX Reference
@article{Wolf_2007_5952,
   author = "Alon Wolf and Amir Degani",
   title = "Recognizing knee pathologies by classifying instantaneous screws of the six degrees-of-freedom knee motion",
   journal = "Medical and Biological Engineering and Computing",
   pages = "475-482",
   publisher = "Springer",
   address = "Berlin / Heidelberg",
   month = "May",
   year = "2007",
   volume = "45",
   number = "5",
}