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INTRODUCTION
Gender specific knee implants have recently
become available based upon the observation
that differences exist in the shape of the knee
between men and women.
Data from literature suggest that for any given
anteroposterior femoral dimension, women
tend to have more narrow mediolateral dimen-
sions than men [9, 16, 19, 20, 21].
The use of standard implants could therefore
in theory lead to mediolateral overhang in
women, causing irritation and pain of the soft
tissue capsular envelope of the knee [4, 5].
The question remains however how valid this
concept is in the patient population undergoing
total knee arthroplasty (TKA), and whether
gender specific components should become
standard in use. The patient population under-
going TKA is indeed predominantly female
and may therefore not necessarily require
female and male versions of all components,
especially for the smaller sizes. A female ver-
sion for smaller sizes and a more male version
for larger sizes could for example be a cheaper
and less inventory requiring solution than pro-
viding a male and female version for all sizes.
Apart from gender, other factors seem howe-
ver to influence the geometry of the knee as
well. Within gender there is indeed a conside-
rable variability in distal femoral and proximal
tibial dimensions. Women for example with
identical anteroposterior (AP) femoral dimen-
sions can have either wide or narrow mediola-
teral (ML) dimensions, indicating that other
variables such as the patient’s specific mor-
photype may play a role.
Morphotypes have classically been categori-
zed as endomorph, mesomorph, or ectomorph
depending on shape and composition of the
individual’s body [14, 15, 22].
Endomorphs are characterized as having a
round body shape with short and taper extre-
mities, mesomorphs have a muscular and V
shaped body constitution, whereas ectomorphs
have a slim and tall morphology with long
arms and legs (fig. 1).
The purpose of our study was therefore to
investigate the influence of morphotype as
well as gender on the actual dimensions of the
distal femur and proximal tibia in the popula-
tion undergoing TKA. Despite the fact that dif-
ferences in shape have been documented bet-
ween male and female knees before, it is less
clear how this is reflected in the population
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THE INFLUENCE OFMORPHOTYPE
AND GENDER ON THE SHAPE
OF THE KNEE IN TKAPATIENTS
J. BELLEMANS