Genu valgum (knock-knee) and genu varum (bow-leggedness) are knee deformities characterized by abnormal alignment and angling of the legs. Treatments include physical examinations, surgical options like guided growth and tibial osteotomy, as well as orthotic management with devices such as the mermaid splint and kafo. Proper assessment and management are crucial to ensure effective correction and mobility improvement for affected patients.

1. Biomechanics of Orthotic
Management of Genu Varum
and Genu Valgum
Bindu Bala
MPO 1st
Year
PDUNIPPD
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2. What is Genu Valgum ?
Genu valgum, commonly called "knock-knee", is a condition
in which the knees angle in and touch each other when the
legs are straightened.
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3. What is Genu Varum ?
Also called bow-leggedness, bandiness,
bandy-leg, and tibia vara, is a varus deformity
marked by (outward) bowing at the knee, which
means that the lower leg is angled inward
(medially) in relation to the thigh axis, giving the
limb overall the appearance of an archer's bow.
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5. How to measure ?
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6. The Q-angle is the angle
formed by a line drawn from
the Anterior superior iliac
spine to(ASIS) to the center
of the patella.
A second line is drawn from
the center of the patella to
tibial tubercle.
The angle formed by the two
lines is called Q-Angle.
The normal Q angle in males
is 140
and in females is 170
.
Q-Angle
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7. Physiological genu varum is a deformity with a tibiofemoral
angle of more than 5 degrees of varus, a radiographically
normal physis , and apex lateral bowing of the proximal end
of the tibia and often distal end of the femur.
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8. Causes
May be seen in one or both the knees
➔ Blount Disease
➔ Rickets
➔ Lateral ligament laxity
➔ Congenital pseudarthrosis of
tibia
➔ Coxa Vara
➔ Obesity
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9. Other Causes
● Infections like
osteomyelitis
● Trauma near
growth epiphysis
of femur or tibia
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10. In Adults
● Osteoarthritis
● Bone softening
diseases such as
Paget’s Disease
● Malunion of lower
part of femur or
upper part of tibia.
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11. Physical Examination
● Bilateral bow leg can be recorded by measuring the
distance between the knees with the child standing and
the heels touching , it should be less than 6 cm.
● McMurray Test-
❏ The patient lies in the supine position with the knee
completely flexed(the heel to the buttock).
❏ The examiner then medially rotates the tibia and extends
the knee. To test the medial meniscus.
❏ Positive test- snap or click is often accompanied by
pain.
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12. ● Varus Stress Test-
❏ Patient is in supine position with the knee fully
extended.
❏ Stabilise the affected leg in slight external rotation
with one hand on the lateral malleolus.
❏ Place the other hand on the medial aspect of the knee and
apply a laterally directed stress on the medial knee.
❏ Flex their knee to 300
and apply the same pressure on the
lateral side to isolate the lateral collateral ligament.
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13. Radiological Examination
Physiological genu varum
nearly always spontaneously
corrects itself as the child
grows.
This usually occurs by the
age of 3-4 years.
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14. TREATMENT
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15. Different procedures ;two main types
➔ Guided growth
This surgery of the growth plate stops
the growth on the healthy side of the
shinbone which gives the abnormal
side a chance to play catch up,
straightening the leg with the child’s
natural growth.
➔ Tibial Osteotomy
In this procedure, the shinbone is cut
just below the knee and reshaped to
correct the alignment.
After Surgery
A cast may be applied to
protect the bone while it
heals
Surgical
Treatment
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16. Mostly used in progressive physiological genu varum but
limited use in pathological genu varum.
Common splints used are- mermaid splint, medial single bar
knee ankle foot orthosis, shoe modification with elevating
inner border of the shoe.
Orthotic Management
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17. PREREQUISITES FOR THE APPROPRIATENESS OF AN
ORTHOSIS
● The affected leg should show no contractures at the hip
and the knee-joint. The patient should be able to stretch
the knee-joint passively without problems.
● The iliopsoas and the gluteus maximus should not be too
weak. In any case, the patient must be able to move the
knee joint back and forth actively and easily while in a
standing position.
● The patient, especially children, must be willing to get
used to the orthosis and practice a certain walking
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18. Single upright KAFO
● Single upright KAFO with
free knee and ankle joints.
● The upright is on the medial
side of the leg for varum
and lateral side for valgum
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19. Story for illustration purposes only
Function
● Used to control genu
Knee movement.
● A ring lock may be used
to control knee flexion
for more smaller,
lightweight patients.
● Ankle varus can be
controlled with the
addition of a T strap.
● Free, limited
motion,dorsiflexion or
plantarflexion may be
incorporated.
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20. Force Systems
The first force system to control genu varum
consists of the following
➔ Force One
A laterally directed force on the
medial,proximal thigh band and cuff.
➔ Force Two
A medially directed force on the lateral
aspect of the knee joint(i.e femoral
condyles)
➔ Force Three
A laterally directed force on the medial
side of the calcaneus by the contour of the
shoe 20

21. Force Systems
The first force system to control genu valgum
consists of the following
➔ Force One
A medially directed force on the lateral
,proximal thigh band and cuff.
➔ Force Two
A laterally directed force on the medial
aspect of the knee joint(i.e femoral
condyles)
➔ Force Three
A medially directed force on the lateral
side of the calcaneus by the contour of the
shoe
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22. Due to the knee being involved the ankle is also affected
● In case of valgus the ankle is under a medially directed
force.
● Also in varus the ankle feels a laterally directed force.
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23. To correct
this lateral
and medial
wedges are
used inside
the shoes
according to
the deformity.
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24. Additional Force
An additional force may
be applied at the ankle
joint with the help of
Lateral T strap or Medial
T strap whichever one is
required.
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25. Mermaid Splint
Used to keep both legs
straight.
Two conjoined polypropylene
valves with soft foam
padding.
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26. Can be used as a night splint also
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