The Knee and Patellofemoral Joints 253Genu Varum
When the angle between the tibia and femur gets
larger and approaches 180°, or the angle of the tibia
relative to the femur actually opens medially versus
laterally, the condition is termed genu varum, or
“bowed legs.” In such a case, when a dancer stands
in a parallel position with the feet touching, there
is space between the knees. If two or more fingers
fit between the knees when the ankles are touch-
ing, this is considered evidence of genu varum. You
can remember this terminology by imagining that
a barrel of rum is being held between the knees,
making the legs bow. In addition to involving the
angle of the femur relative to the tibia, this condi-
tion often involves an actual lateral bowing of the
femur or tibia itself (or of both) (figure 5.11A). This
positioning is of concern in terms of aesthetics, the
resultant increased load on the medial meniscus and
increased tension on the lateral collateral ligament,
and the associated tendency to “roll out” (excessive
supination). However, a high prevalence of genu
varum has been noted in elite athletes, and it is
interesting that orthopedic evaluation of 40 elite
ballet students revealed that 46% demonstrated genu
varum (Hamilton et al., 1997). So, although extreme
genu varum may be detrimental, a small amount
appears to be aesthetically acceptable, as evidenced
by its presence in elite dancers. Its potential implica-
tions for injury risk will require additional study.Genu Recurvatum
When one views the knees from the side, the knees
can appear slightly bent, straight (extended), or
hyperextended as seen in figure 5.11B. When the
knees are hyperextended, this is termed genu
recurvatum (L. genu, knee + re-curvus, bent back), or
“back-knee,” as the knees curve backward predomi-
nantly in the sagittal plane. Genu recurvatum is more
common in females than males, and more common in
individuals of any gender with generalized joint laxity
(“hypermobility”). In the dance arena, hyperextended
knees are sometimes wrongly attributed to excessive
strength and use of the quadriceps femoris. However,
since this hyperextension actually is often associated
with attempting to maintain stability by “hanging” on
ligamental constraints versus using muscular control,
knee hyperextension is actually associated with less
activity of the quadriceps than in subjects who stand
with the knees slightly bent (Basmajian and DeLuca,
1985) and is often associated with weak quadriceps
(Scioscia, Giffin, and Fu, 2001).Knee Alignment: Valgus Angulation
Perform the following observations, and use figure 5.11 as a reference to identify your valgus angula-
tion.- Stand facing a mirror with your feet parallel and approximately hip-width apart. Observe the
relationship between the hip, knee, and ankle joints. Due to the slight inward angulation of the
femur, with normal valgus angulation the tibia should angle out just slightly relative to the femur
so that an angle is formed between these bones of about 170°. Note whether your angle seems
less than, greater than, or about equal to 170°. - Now, move your feet together so that the inner borders touch, and note the position of your knees.
With normal alignment, the knees also are approximately touching. However, if when standing in
this position you can see space between your knees, this is suggestive of the presence of genu
varum, or “bowed legs.” - In contrast, if you are unable to bring your feet together because your knees make contact well
before the inner borders of your feet can touch, this is suggestive of the presence of genu valgum,
or “knock-knees.” - After identifying the alignment of your knees, slowly move the pelvis between positions of anterior
tilt, neutral, and posterior tilt, and note if and how they influence your knee alignment.