Jc. Wolchok et al., THE EFFECT OF INTERSEGMENTAL KNEE MOMENTS ON PATELLOFEMORAL CONTACT MECHANICS IN CYCLING, Journal of biomechanics, 31(8), 1998, pp. 677-683
The aim of this study was to evaluate the effect of bicycle pedal desi
gn on the mechanics of the patellofemoral joint. Previous research det
ermined that for certain riders the non-driving varus and internal kne
e moments could be reduced by switching from fixed to free floating pe
dals (Ruby and Hull, 1993). It was postulated that the presence of var
us and internal knee moments during fixed pedal cycling may adversely
affect patellofemoral joint contact mechanics which could lead to the
development of anterior knee pain. To investigate the effect of pedal
design the hypothesis that varus and internal intersegmental knee mome
nts significantly increase patellofemoral contact pressure, contact ar
ea and contact force was tested. To test this hypothesis cycling loads
were simulated in vitro using a six-degree-of-freedom load applicatio
n system (LAS). Using the LAS, varus moments ranging from 0-20 Nm and
internal knee moments ranging from 0-10 Nm were applied simultaneously
with quadriceps force at knee flexion angles of 60 and 90 degrees. Pa
tellofemoral contact patterns were measured using pressure sensitive f
ilm. An applied 10 Nm internal moment significantly increased both con
tact area by 16% and contact force by 22% at 90 degrees of flexion. Th
e application of a 20 Nm varus moment modestly yet significantly incre
ased contact area by 6% and contact force by 5%. When applied in combi
nation, varus and internal knee moments increased contact area and for
ce by as much as 29% and 28% respectively. The mean contact pressure w
as not significantly increased by either of the two moments. The resul
ts suggest that non-driving intersegmental knee moments subject the pa
tellofemoral joint to loads and contact patterns which may accelerate
the development of chondromalacia. (C) 1998 Elsevier Science Ltd. All
rights reserved.