Proximal femoral focal deficiency

Dear Editor,

Proximal femoral focal deficiency (PFFD) is an extremely rare anomaly with an incidence of 1–2 per 1,00,000 births. It is characterized by dysgenesis and hypoplasia of variable segments of the proximal femur, in which the defect ranges in severity from femoral shortening associated with varus deformity to complete absence of both the acetabulum and proximal femur.¹

A 3-month-old female infant, born to parents of non-consanguineous marriage, presented with complaints of limb discrepancy, with a short left thigh as compared with right since birth. On examination, the left thigh was shorter in length, with lesser skin folds, as compared with the right thigh. Galeazzi sign was positive with the left knee lower than the right (Fig. 1). There were no other skeletal or systemic anomalies noted. Clinically, the first impression was developmental dysplasia of the hip (DDH); however, short thigh length was peculiar in this case. The radiograph of the pelvis and thighs clinched the diagnosis, as it revealed partial absence of the proximal end of the left femur shaft with presence of head (Fig. 2). Computerized Tomography (CT) scan or Magnetic Resonance Imaging (MRI) was not performed in our case, neither was any antenatal scan available. Patient/ guardian consent was obtained for use of images in the study.

Fig. 1.

Positive Galeazzi sign.

Fig. 2.

Partial absence of the proximal end of the femur shaft.

Both DDH and PFFD may present as limb shortening. In DDH, the femoral head may or may not be dislocatable with restricted hip abduction of the affected side. There is limitation of abduction, and apparent shortening presents with asymmetry of thigh folds. However, in PFFD, the shortening is usually more significant, which usually remains constant with growth. The affected limb may be at the level of the mid tibia (Gillespie A) or knee (Gillespie B) of the contralateral side. In rare cases, there may be subtotal absence of the femur (Gillespie C). In PFFD, the affected hip is in attitude of flexion, abduction, and external rotation.

The etiological factors of PFFD described in the literature such as suboptimal control of diabetes during the early weeks of pregnancy, any history of exposure of drugs such as thalidomide, viral infections, radiation, and trauma were not there in our case.² Congenital hypoplasia of the femur may have either of the these following four presentations: these are isolated PFFD, femoral hypoplasia-unusual facial syndrome, femur/fibula/ulnar hypoplasia, and limb/pelvis-hypoplasia/aplasia syndrome.³ Management of isolated PFFD requires an individualized approach, based on leg length discrepancy and the status of the musculature.⁴ Available surgical options include Pelvi-femoral osteotomies for hip reconstruction, Van- Nes Rotationplasty, femoral Derotation and Valgus Osteotomy for hip stabilization and Limb lengthening procedures using Distraction Osteogenesis. A mild deficiency may only need a prosthesis support. The long-term prognosis after surgical correction is usually good.^4,5 Our case was type A as per Aitken classification. Hip stabilization was planned with limb lengthening at a later date.