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· DOS Abstracts
Composition of The Knee Index, a novel three-
dimensional biomechanical index for knee joint load,
in subjects with mild to moderate knee osteoarthritis
Brian Clausen, Thomas Andriacchi, Dennis Brandborg Nielsen, Ewa Roos,
Anders Holsgaard-Larsen
Department of Sports Science and Clinical Biomechanics, University of
Southern Denmark; Department of Mechanical Engineering, Department
of Orthopedic Surgery, Stanford University, Stanford, USA; Veterans
Administration, Palo Alto; Department of Orthopaedics and Traumatology,
Department of Clinical Research, Odense University Hospital, University of
Southern Denmark
Background:
Knee joint load is an important factor associated with progression
of knee osteoarthritis. To provide an overall understanding of knee joint load-
ing, the Knee Index (KI) has been developed to include moments from all three
planes (frontal, sagittal and transversal). However, before KI is used in clinical
trials a biomechanical analysis identifying the respective contributions of the
knee moments derived from the three planes is needed.
Purpose / Aim of Study:
The purpose of this study was therefor to investi-
gate how the frontal, sagittal and transversal moments contribute to KI, a novel
biomechanical index of joint load for the knee, in patients with mild to moderate
knee osteoarthritis.
Materials and Methods:
The contribution of frontal, sagittal and transversal
plane knee moments to KI was investigated in 24 subjects (13 women, age: 58
± 7.6 years, BMI: 27.1 ± 3.0) with clinically diagnosed mild to moderate knee
osteoarthritis according to the ACR criteria. Three dimensional gait analysis was
performed. Subjects walked barefoot at self-selected walking speed. The first
peak magnitude KI from all three planes were calculated using inverse dynam-
ics.
Findings / Results:
Frontal plane kinematics contributed with 59.3% (SD
25.6) of KI while sagittal plane kinematics contributed with 40.5% (SD 26.1). A
substantial inter-subject variation in the relative contribution of the flexion and
extension moment components to KI was observed.
Conclusions:
Our findings support the notion that the primary contributor to
KI is the frontal plane kinematics (i.e. the knee adduction moment), and sec-
ondarily the sagittal plane kinematics (i.e. the knee flexion moment). This holds
promise for using KI in clinical trials since both frontal and sagittal knee joint
moments have been suggested to be associated with the knee osteoarthritis
disease progression.
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