fibular hemimelia

1. Abstract
Fibular Hemimelia - A Case Report
Department of Obstetrics & Gynaecology, St.Martha’s hospital, Bangalore
Fibular Hemimelia (FH) is a rare disorder; it may occur as an
isolated anomaly or as a part of a malformation syndrome. We
present a case of fibular hemimelia in a neonate with foot
deformity with normal prenatal ultrasound. The purpose of the
present report is to create the awareness of the condition and
to review the literature.
Introduction
(EM) LSCS was done in view of absent beat to beat
variability, variable deceleration, no acceleration in the
admission CTG. Intraoperatively, liquor was clear ,female
baby delivered, cried immediately after birth, anterior bowing
of right lower limb noted with absence of second toe. Baby
was handed over to pediatrician for further evaluation.
Following investigations were done:
1) Infantogram – congenital absence of fibula , absent meta-tarsal
bones and absent right head of tibia epiphysis.
2) Abdominal scan – normal study
3) Cranium scan – normal study
4) Echo – small PDA
Case
Discussion Conclusion
This case highlights the difficulty of antenatal diagnosis
of FH, which has been recognized in literature. It is
particularly difficult if it is present in one limb. Part of the
difficulty may be the fact that it is so rare. In a selected “high-risk”
patient population scanned trans-vaginal scan between
12 and 16 weeks, Bronshtein et al found the incidence of
skeletal anomalies to be 0.57% (42 cases in 7325 scans).4 In
contrast, the frequency of these anomalies in the general
population is extremely low. This discrepancy may be due to
the fact that their patients were high risk and because at
fetuses affected by skeletal dysplasia are at an increased risk
for intrauterine death.
Development of the fetal upper and lower extremities
has been documented by USG. Both the upper and lower buds
are seen by the end of the 8th week of gestation.
Subsequently, there is rapid growth of both upper and lower
extremities, and by the end of the 10th week, the entire limbs
are developed. With 4-dimensional USG, these early fetal
movements can be documented. The fetal long bones can be
evaluated and measured by the end of the first trimester (10th–
12th week)5
The precise etiology of FH is unclear.6 However, several
theories have been suggested, such as defects in the apical
ectoderm ridge, defects secondary to an absent anterior tibial
artery and defects in muscle development. Another proposed
theory is that of a disruption of the lower limb developmental
field during embryogenesis. The developmental field of the
lower extremity includes the pubic portion of the pelvis,
proximal femur, patella, anterior cruciate ligament, and lateral
or axial foot rays. This developmental field encompasses the
commonly associated defects seen with FH, namely of the
femur and lateral aspect of the foot.
Classification
Achterman and Kalamachi classification, derived from
clinical as well as radiographic information.
Type I, there is minimal hypoplasia of the fibula,
Type II-there is complete absence of fibula.
The therapies for FH are surgical and include limb-lengthening
procedures and amputation. The decision to
proceed with one or the other is usually individualized from
case to case, but in cases in which there is a nonfunctional foot
or a limb length discrepancy of greater than 30%, surgical
amputation with early use of a prosthesis is generally
recommended.
An obvious fetal malformation may not be apparent until all
the long bones are carefully measured and evaluated. This can
further be challenging when only 1 limb or part of a limb is
affected.
The AIUM(American Institute of Ultrasound in
Medicine) Practice Guideline for the Performance of an
Antepartum Obstetric Ultrasound Examination recommends
documenting the presence or the absence of the fetal
extremities during the second trimester of pregnancy.
Therefore detailed fetal anatomical survey is
recommended at time of routine scan, which can be difficult
in Indian scenario. Explanation of the condition to the parents
poses further challenges.
References
1. Florio I, Wisser J, Huch R, Huch A. Prenatal ultrasound diagnosis of a
femur-fibula-ulna complex during the first half of pregnancy. Fetal Diagn
Ther 1999; 14:310–312.
2. Coventry MB, Johnson EW JR. Congenital absence of the fibula. J Bone
Joint Surg Am 1952; 34:941–955.
3. Lewin SO, Opitz JM. Fibular a/hypoplasia: review and documentation of
the fibular developmental field. Am J Med Genet Suppl 1986; 2:215–238
4. Bronshtein M, Keret D, Deutsch M, Liberson A, Bar Chava I.
Transvaginal sonographic detection of skeletal anomalies in the first and
early second trimesters. Prenat Diagn 1993; 13:597–601.
5. Monteagudo A, Dong R, Timor-Tritsch IE.Fetal fibular hemimelia: case
report and review of the literature Ultrasound Med. 2006;25:533-7.
6. Fordham LA, Applegate KE, Wilkes DC, Chung CJ. Fibular hemimelia:
more than just an absent bone. Semin Musculoskelet Radiol 1999; 3:227–
238.
The incidence of fibular has been estimated to be 5.7 to
20 cases per million births.1 In most cases, it represents an
isolated and sporadic event. However, FH may be a part of a
malformation syndrome. Even , though this a rare condition ,
it is the most common malformation among the long bone
deficiency disorders.2
Shortening of the extremity is obvious at birth with leg-length
discrepancy. On plain radiograph of the leg and foot,
significant fibular deficiency (hypoplasia) or absence of the
fibula can be seen.
Fibular hemimelia is actually a clinical spectrum
ranging from mild fibular hypoplasia to fibular aplasia. The
complete form is more common than the incomplete form;
unilateral involvement is more common than bilateral; and the
right side is more commonly affected than the left.3
Bilateral FH is seen in approximately one third of cases.
In these cases, the tibiae are often straight. When FH is
unilateral, the right side is more commonly affected, and
anterior tibial bowing is usually present. In almost all cases,
there is deficiency of the lateral foot rays. Less commonly,
there is fibular aplasia with a normal number of toes, but
almost never associated with polydactyly. It is twice as
common in male fetuses as in female fetuses.
Fig. 2: Limb length discrepancy
A 23 years old, primigravida with non consanguineous
marriage, with uneventful antenatal period. Scan done in first
and second trimester was unremarkable. She presented at
40+5 weeks of gestation in latent labor.
Garima Nag, Diana Bernard, Padmini Issac
Fig. 1: Right leg bowing and shortening with absent 2nd toe.
Fig. 3: Right fibular absence in the lower extremity radiograph
Fig. 4: Infantogram
Treatment options of limb lengthening procedure/ amputation was
explained to the parents.
Contd….