Affiliations: [a] Faculty of Medicine, University of Toronto, Toronto,
P. Ont M5T 1W5., Canada | [b] Department of Health and Behavior, Columbia
University, Teachers College, New York, NY 10027, USA
Note: [] Address for correspondence: Dept. of Health and Behavior
Studies, Box 114, Teachers College, Columbia University, 525W 120 Street, New
York, NY 10027, USA. Tel.: +1 212 606 1211; Fax: +1 212 678 4048;
E-mail:rm226@columbia.edu
Abstract: Background: In earlier work we noted that women with medial
compartment knee osteoarthrosis and varus deformity displayed greater
neuromuscular deficiencies of quadriceps muscles than those with normal tibial
alignment when tested isokinetically at 90° sec^{-1} and
at 0° sec^{-1} using an isokinetic dynamometer. Purpose: The present purpose was to provide further insight into the
potential influence of muscular factors in the development of medial
compartment knee osteoarthrosis. Methods: Because our previous findings indicated significantly
greater torque generating problems at higher isokinetic speeds than lower
speeds among adults with varus alignment deformities, and prior work is
strongly associated with isometric test outcomes, we elected to perform
quantitative measures of maximal isometric knee torques generated 0°
sec^{-1} and to compare these to validated goniometric
alignment measures of the lower legs of 14 health individuals exhibiting genu
varum on a single test occasion. Results. The analyses revealed: 1) a significant inverse
relationship between the right quadriceps and hamstrings muscle torque and
right tibia varus measures (r=-0.59; r=-0.66), and between the left hamstrings
muscle torque and left tibia vara measures (r=-0.62) (p < 0.05) when
controlling for gender; 2) antagonist-agonist knee torque ratios that tended to
vary inversely with the magnitude of the prevailing varus deformity; 3) the
presence of asymmetric tibia vara magnitudes with greater angulations recorded
for the subject's right side, regardless of limb dominance; 4) greater varus
angulation deformities for both legs of the males compared to the females (p
< 0.05). Conclusions: The slope of the regression line linking the maximal
knee extensor and flexor torques of healthy young adults tends to vary
inversely with the degree of varus angulation as presently recorded. There may
be considerable intra-individual and gender differences in the manifestation of
this finding. These observations may have a bearing on the etiology and
pathogenesis of uni- or bilateral medial compartmental knee joint disease in
healthy adults exhibiting genu varum, hence warranting further study using more
sophisticated measures and isokinetic testing at different angular
velocities.
