Intoeing, knock-knees, and bowlegs

Intoeing, knock-knees, and bowlegs
COMPETENCY- The resident should be able to define intoeing, knock-knees, and bowlegs,
develop a differential diagnosis for these common musculoskeletal problems, and know the
management of these problems, particularly with respect to the need for referral to a specialist.
CASE- A mother and her 5-year-old son present to your clinic for a well child check. The
mother has noted that the child continues to walk “pigeon-toed” and it seems to be getting worseshe has noted that he has been tripping more frequently. She is worried that his legs are growing
incorrectly and if nothing is done, he will have problems walking for the rest of his life. His
mother thinks that he needs leg braces because one of her brothers needed them when he was a
child, and now he has no problems walking. What do you tell her?
QUESTIONS1. What are the definitions of intoeing, knock-knees, and bowlegs?
2. What is normal lower extremity development?
3. What are the causes and differential diagnosis of intoeing, knock-knees, and
bowlegs?
4. How are intoeing, knock-knees, and bowlegs diagnosed? Are radiographs necessary
to confirm the diagnosis?
5. What is the current management of intoeing, knock-knees, and bowlegs, and when
should a child be referred to a specialist?
REFERENCES:
1. Behrman R, Kleigman R, Jensen H, eds. Nelson’s Textbook of Pediatrics. W.B.
Saunders, Philadelphia 2003: 2261-9.
2. Bruce, RW. Torsional and Angular Deformities. Pediatric Clinics of North America.
1996; 43: 867-81.
3. Greene, Walter B., ed. Essentials of Musculoskeletal Care. Academy of Orthopaedic
Surgeons, Rosemont, IL 2001: 662-669.
4. Sass, P & Hassan, G. Lower Extremity Abnormalities in Children. American Family
Physician. 2003; 68: 461-9.
5. Scherl, Susan, Common Lower Extremity Problems in Children. Pediatrics in Review.
2004; 25: 43-75.
Intoeing, knock-knees, and bowlegs
COMPETENCY- The resident should be able to define intoeing, knock-knees, and bowlegs,
develop a differential diagnosis for these common musculoskeletal problems, and know the
management of these problems, particularly with respect to the need for referral to a specialist.
CASE- A mother and her 5-year-old son present to your clinic for a well child check. The
mother has noted that the child continues to walk “pigeon-toed” and it seems to be getting worseshe has noted that he has been tripping more frequently. She is worried that his legs are growing
incorrectly and if nothing is done, he will have problems walking for the rest of his life. His
mother thinks that he needs leg braces because one of her brothers needed them when he was a
child, and now he has no problems walking. What do you tell her?
QUESTIONS1. What are the definitions of intoeing, knock-knees, and bowlegs?
Intoeing, commonly called pigeon-toed, means that the foot turns in more than expected
during walking and running. It is a rotational, or torsional, deformity.
Genu varum, commonly referred to as bowlegs, is alignment of the knee with the tibia
medially deviated (varus) in relation to the femur. Genu valgum, commonly referred to as
knock-knees, is alignment of the knee with the tibia laterally deviated (valgus) with relation
to the femur. They are classified as angular deformities.
2. What is normal lower extremity development?
The vast majority of the time these conditions are physiologic variants of normal, and a
common progression of these conditions through early childhood has been well described. In
the typical in utero position, the hips are flexed, abducted, and externally rotated; the knees
are flexed and the lower legs are internally rotated; and the feet are in slight equinus,
supinated, and in contact with the posterolateral aspect of the opposite thigh. The
combination of external rotation of the hip and internal rotation of the lower leg produces a
bowed appearance of the lower extremities when the child begins to ambulate. Thus, all
babies are born bowlegged, usually at an angle of 10-15°. Over the first 3 years of age, the
bowing gradually straightens and the child progresses to genu valgum, with maximum
valgum of 10-15° by age 3-4 years. This development then progresses back to the normal
mild valgum seen in adulthood by age 7-8.
Intoeing in general can be considered congenital, resulting from the positioning of the fetus
inside the womb. However some specialists believe that medial femoral torsion, a form of
intoeing, is an acquired rotational defect caused by increased loading of the femur while in
torsion.
3. What are the causes and differential diagnosis of intoeing, knock-knees, and bowlegs?
Intoeing
Physiologic
Femoral anteversion
Metatarsus adductus
Tibial torsion
Pathologic
Clubfoot
Cerebral palsy or other neuromuscular
disorders
Intoeing has three possible locations of origin: the foot, between the knee and the ankle, and
between the hip and the knee. When the origin is the foot, the physiologic condition is
known as metatarsus adductus, although this needs to be distinguished from clubfoot. When
the origin is between the knee and the foot, it is known as tibial torsion. And when the origin
is between the hip and the knee, it is known as medial femoral torsion. Tibial torsion is the
most common cause of intoeing in children younger than three years of age, while medial
femoral torsion is the most common cause in children older than three years of age.
Genu valgum/varum
Physiologic
Metabolic
Rickets
Renal osteodystrophy
Trauma
Tumor
Infection
Blount’s disease
Osteochondrodysplasia
Multiple epiphyseal dysplasia
Metaphyseal dysplasia
4. How are intoeing, knock-knees, and bowlegs diagnosed? Are radiographs
necessary to confirm the diagnosis?
Intoeing, knock-knees, and bowlegs are clinical diagnoses. Often, a simple yet
thorough history and physical can exclude pathologic causes of these lower extremity
deformities. Emphasis should be placed on the family history, growth, development,
and the age of onset and progression of the deformity. Height and weight should be
plotted on a growth curve. Gait should be observed.
For a child in which a rotational deformity (i.e. intoeing) is observed, the physician
can perform a series of simple tests called a rotational or torsional profile; this can
help differentiate the anatomic basis (foot, leg, or thigh) of the abnormality, while
also allowing the physician to chart progress in subsequent visits. The rotational
profile includes measurement of the foot progression angle, forefoot alignment, hip
rotation, and the thigh-foot angle.
The foot progression angle determines whether a child is intoeing or outtoeing. It is
the angle made by the foot with respect to a straight line plotted in the direction the
child is walking. If the long axis of the foot is directed outwardly, the angle is
positive. If the foot is directed inwardly, the angle is negative and is indicative of intoeing. (From Thompson GH: Gait disturbances. In Kliegman RM [editor]: Practical
Strategies in Pediatric Diagnosis and Therapy. Philadelphia, WB Saunders, 1996.)
Forefoot alignment is a gross measurement of the degree of adduction of the sole of
the foot; it is a simple check for metatarsus adductus. This can be quantified by
extrapolating a line bisecting the heel up to the forefoot. Normally, this line bisects
the forefoot between the second and third toes. Hitting the fourth or fifth toe with the
imaginary bisector quantifies the degree of adduction and hence, metatarsus adductus.
Hip rotation approximates femoral torsion. The child should be placed in the prone
position, with the knee flexed to 90°. Each leg should be measured for internal and
external rotation. On outward rotation (A), the leg produces internal hip rotation; and
on inward rotation (B), the leg produces external hip rotation. Children older than 2
years of age should have approximately 45° of both internal and external rotation.
Excessive internal rotation (greater than 65°) coupled with limited external rotation
indicates femoral torsion. (From Thompson GH: Gait disturbances. In Kliegman RM
[editor]: Practical Strategies in Pediatric Diagnosis and Therapy. Philadelphia, WB
Saunders, 1996.)
Finally, the thigh-foot angle describes the degree of tibial torsion. Once again, with
the child prone and the knee flexed to 90°, an imaginary line is drawn down the
center of the thigh. The angle this line makes with the heel bisector is the thigh-foot
angle and should measure 0-10 degrees. Intoeing angles are given negative values
and outtoeing angles are given positive values. External tibial torsion (A) produces
excessive outward rotation. Normal alignment (B) is characterized by slight external
rotation. Internal tibial torsion produces inward rotation of the foot and is a negative
angle (C). (From Thompson GH: Gait disturbances. In Kliegman RM, Nieder ML,
Super DM [editors]: Practical Strategies in Pediatric Diagnosis and Therapy.
Philadelphia, WB Saunders, 1996.)
The transition from bowlegs to knock-knees can be followed by measuring the
distance between the knees (with the ankles held together) for children with genu
varum (bowlegs) or the distance between the ankles (with the knees held together) for
children with genu valgum (knock-knees). This can be done every six months.
Radiographs are not necessary to diagnose intoeing, knock-knees, or bowlegs.
However, radiographs should be obtained if a pathologic condition is suspected, as in
cases that have one or more of the following: (1) the deformity is unilateral, (2)
significant asymmetry, (3) painful, (4) height below the 5th percentile, (5) genu varum
or valgum greater than two standard deviations from normal for the child’s age, (6)
family history of pathologic conditions, (7) rapid progression of the deformity, or (8)
persistence of genu varum beyond the expected time frame.
5. What is the current treatment of intoeing, knock-knees, and bowlegs, and when
should a child be referred to a specialist?
For the majority of cases of intoeing, treatment is rarely necessary; the deformities
generally correct spontaneously over childhood. Corrective braces, shoes, and casts
have not been shown to be of any benefit. Thus an explanation and parental
reassurance are often all that is needed. This includes mild metatarsus adductus,
tibial torsion, and medial femoral torsion (femoral anteversion). For moderate
metatarsus adductus, stretching exercises consisting of gentle laterally directed
pressure on the first metatarsal can be performed on the child during diaper changes.
In the rare cases of severe or rigid metatarsus adductus, “stretch casting” or a
Wheaton brace can be applied by an orthopedist to the affected extremity, although as
stated, some controversy exists whether these affect the natural history of the
disorder. Further, there is no evidence that persistent intoeing leads to any significant
problems in adulthood. In fact, there is some evidence to suggest that persistent
intoeing can be of some benefit in sports that require quick directional shifts, such as
basketball, soccer, and tennis. Referral to a specialist is only warranted if the
deformity is severe and causing functional impairment, and other pathologic
conditions have been ruled out.
As previously explained, bowlegs and knock-knees are usually part of a natural
continuum of growth, with most children reaching the typical adult knock-kneed
configuration by age 7. Once again, an explanation and parental reassurance are
often all that is needed. Pathologic conditions often reveal themselves after a careful
history and physical, with basic knowledge of normal growth patterns and a growth
chart. If the deformity is unilateral, painful, or very asymmetric, or the child’s growth
or development trend appears to deviate from normal, radiographs should be obtained
and further evaluation by a specialist should be pursued.
REFERENCES:
6. Behrman R, Kleigman R, Jensen H, eds. Nelson’s Textbook of Pediatrics. W.B.
Saunders, Philadelphia 2003: 2261-9.
7. Bruce, RW. Torsional and Angular Deformities. Pediatric Clinics of North
America. 1996; 43: 867-81.
8. Greene, Walter B., ed. Essentials of Musculoskeletal Care. Academy of
Orthopaedic Surgeons, Rosemont, IL 2001: 662-669.
9. Sass, P & Hassan, G. Lower Extremity Abnormalities in Children. American
Family Physician. 2003; 68: 461-9.
10. Scherl, Susan, Common Lower Extremity Problems in Children. Pediatrics in
Review. 2004; 25: 43-75.
Submitted by Jon Gugel
Reviewed by Catherine Glunz