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