Congenital deficiency of the proximal femur, literature review with a case report
Congenital anomalies of the femur are very uncommon, it is of extreme importance that every case of rare congenital deformity coming under the care of the surgeon should be reported, as it may be helpful in further investigations both of an embryological and an anatomical nature. Here by we are presenting a rarity of congenital deficiency of the proximal femur in a child of 3 months.
Congenital anomalies of the femur and fibular aplasia/hypoplasia are considered as the main anomalies involved in congenital asymmetry of the lower limbs. Congenital anomalies of the femur is a rare anomaly, occurring with a frequency of approximately 0.2/10,000 live births. Congenital anomalies of the femur is described as an outbreak of femoral hypoplasia or aplasia, isolated or associated with fibular and/or ulnar anomalies. It is an uncommon congenital defect that involves the femur and acetabulum in varying degrees. It can either be isolated or in combination with other defects of the lower limbs including absence or hypoplasia of the patella, fibular a/hypoplasia and absence of lateral foot rays. 1-3
The female infant of 12 weeks was brought to the hospital with complains of shortening of left lower limb and unable to move that limb, this was the first child, pregnancy and labor being without difficulty. Both parents were 30 years old. Family history and pregnancy were unremarkable. There was no history of maternal diabetes or exposure to any teratogenic agent during the pregnancy. The baby was delivered spontaneously at 39 weeks of gestation. Birth weight was 3500 g (50th centile), length was 50 cm (50th-75th centile), and occipitofrontal head circumference was 34 cm (25th-50th centile). Baby was well nourished for her age, the left lower extremity which is much shorter than the right, In the supine position the child held the left lower extremity in the frog position. Upon standing on the right leg, the left was held in ninety degrees’ external rotation. The child could stand on the left leg by flexing the right knee. Strength of the muscles was good. There is a congenital abnormality of the left femur with a complete absence of the upper half of the femur. The lower portion of the shaft gradually tapers to a point, and ends five centimeters above the epiphyseal line. The upper extremity of this rudimentary bone found in external and superior to the site of the acetabulum, which was undeveloped. The knee joint was clear and normal. The right femur was normal in development and measures sixteen centimeters from the upper to the lower epiphyseal line. The right hip and knee joints were normal. There was no pathology on chest roentgenograms and abdominal ultrasonography. Routine laboratory tests and ophthalmological examination were also normal. Peripheral blood chromosomal analysis showed normal male karyotype (46, XY). The physical examination of the parents including their limbs was normal.
Proximal femoral focal deficiency is a rare malformation of the lower limbs that involves the femur and acetabulum in varying degrees. It may occur with or without fibular hemimelia and can be unilateral or bilateral in presentation. 4 Fibular a/hypoplasia covers a spectrum of malformations including variable degrees of fibular a/hypoplasia ,shortening of the tibia and femur, genu valgum and lateral femoral condyle hypoplasia, knee ligament laxity, tibial bowing, ball and socket ankle joint, tarsal coalitions and missing lateral rays of the foot . 5 It has long been suggested that the basis of such anomalies may involve an alteration of limb “developmental fields”, i.e., tibial and fibular fields 6. However, a specific genetic cause, such as mutations involving a specific gene family, etc., has not been elaborated yet. One such affected putative gene family may be the Hox gene family involved in skeletogenesis both axial and appendicular, as well as in other systems such as the urogenital system 7. The etiology of proximal femoral focal deficiency is unknown. It is known that the development of the limb buds takes place early in fetal life, beginning at about four weeks’ gestation. Various factors act upon the developing limb, resulting in rotation, segmentation, longitudinal growth, and differentiation of elements. The most proximal elements of the limb develop first 8, 9 and the hand and foot follow, being fully formed by the seventh week. Chemical toxicity,radiation,enzyme alterations, viral infections, and mechanical trauma 10 have produced limb anomalies in humans and experimental animals. Ring has stated that the primary problem is in the enchondral ossification of defective cartilage. Gardner 9 pointed out that failure of skeletal elements to form may be due to factors operating during the period of differentiation. This critical period-at four to eight weeks of fetal life-was defined by studies of thalidomide babies. It is apparent from these and other studies that as the severity of the defect increases, so does the incidence of associated anomalies. The theory advanced by Morgan and Somerville 10. that mechanical trauma to the advancing growth plate interferes with the development of normal infantile valgus, may be appropriate for simple coxa vara, but it does not explain the wide dissociation of fragments seen in the typical case of Proximal femoral focal deficiency.
Fig 1: Radiographic images of the lower extremities and pelvis showing Normal right lower extremity and Affected left extremity
1. Hamanishi C. Congenital short femur. Clinical, genetic, and epidemiological comparison of the naturally occurring condition with that caused by thalidomide. J Bone Joint Surg Br 1980; 62: 307-320.
2. Sorge G, Ardito S, Genuardi M, et al. Proximal femoral focal deficiency (PFFD) and fibular a/hypoplasia (FA/H): a model of a developmental field defect. Am J Med Genet 1995; 55: 427-432.
3. Ashkenazy M, Lurie S, Ben-Itzhak I, Appelman Z, Casbi B. Unilateral congenital short femur: a case report. Prenatal Diagn 1990; 10: 67-70.
6. Lewin SO, Opitz JM. Fibular a/hypoplasia: review and documentation of the fibular developmental field. Am J Med Genet 1986; 91: 347-356.
7. Goodman FR. Limb malformation and the human Hox genes. Am J Med Genet 2002; 112: 256-265.s been suggested that 1938 and 1948).
8. Borggreve, J., Kniegelenksersatz dutch das in der Beinlangsachse um 180′ gedrehte Fussgelenk. Arch. Orthopad. Chir. 28:175-178. 1930.
9. Gardner, E. D. The development and growth of bones and joints. A.A.O.S. Instructional Course Lecture. J. Bone Joint Sure. 45A(4):856-862, 1963.
10. Morgan, J. D., and E. W. Somerville. Normal and abnormal growth at the upper end of the femur. J. Bone Joint Surg. 42B:264-272, 1960.
About the Author:
Dr Ramji lal Sahu
Associate professor, Department Of Orthopaedics, SMS and RI, Sharda University.
Greater Noida, U. P., India
Contact: Mobile no. 09871120703, Email firstname.lastname@example.org