This analytical work supports the ongoing research effort entitled “Orthopaedic Alignment & Screw Imaging Systems (OASIS)” as funded by the FCT (PTDC/DES/119559/2010). Experimental data were provided for validation through the Grand Challenge Competition to Predict In Vivo Knee Loads, a part of the Symbiosis Project funded by the National Institutes of Health (NIH) through the NIH Roadmap for Medical Research (Grant U54 GM072970). Author SSK also acknowledges support from the NIH (Grant P20 MD003350).
Journal of Novel Physiotherapies
Analysis of variance, Knee -- Anatomy, Knee -- Range of motion --Measurement, Constraints (Physics) -- Applications to biomechanics
Researchers have reported several compensation methods to estimate bone and joint position from a cluster of skin-mounted markers as influenced by Soft Tissue Artifacts (STA). Tikhonov Regularization Filtering (TRF) as a means to estimate Instantaneous Screw Axes (ISA) was introduced here as a means to reduce the displacement of a rigid body to its simplest geometric form. Recent studies have suggested that the ISA of the knee, i.e., Knee Functional Axes (KFA), might be closely connected to the estimation of constraint forces such as those due to medial and lateral connective tissues. The estimations of ISAs were known to be highly sensitive to noisy data, which may be mathematically ill-posed, requiring smoothing such as that conducted by regularization. The main contribution in this work was to establish the reciprocal connection between the KFA and Ground Reaction Forces (GRF) as a means to estimate joint constraint forces. Presented results compare the computational performance with published kinetic and kinematic joint data generated from an instrumented total knee replacement. Implications of these preliminary findings with respect to dynamic alignment as a functional anatomic metric are discussed.
Kim W, Kim YH, Veloso AP, Kohles SS (2013) Tracking Knee Joint Functional Axes through Tikhonov Filtering and Plűcker Coordinates. J Nov Physiother S4: 001. doi:10.4172/2165-7025.S4-001