Title : proximal femoral focal deficiency A case report

Background Proximal Femoral Focal Deficiency (PFFD) is an extremely rare condition, with an incidence of 1-2 per 100,000 births. It is characterized by dysgenesis and hypoplasia of varying segments of the proximal femur. The severity of the defect ranges from femoral shortening with varus deformity to complete absence of both the acetabulum and proximal femur.

Case Presentation A 7-month-old male infant, born to consanguineous parents, presented with limb discrepancy, noting a shorter left thigh compared to the right since birth. On examination, the left thigh was shorter and had fewer skin folds compared to the right. The Galeazzi sign was positive, with the left knee lower than the right. No other skeletal or systemic anomalies were observed. Although developmental dysplasia of the hip (DDH) was initially suspected, the short thigh length was unusual. Radiographs of the pelvis and thighs confirmed the diagnosis, revealing partial absence of the proximal end of the left femur shaft with the femoral head present. CT or MRI was not performed. Antenatal scans at 36 weeks showed a breech presentation with a short left femur (35 mm, corresponding to 21 weeks and 2 days) and a right femur (65 mm, corresponding to 34 weeks and 5 days).

Discussion Both DDH and PFFD can cause limb shortening. DDH is characterized by limited hip abduction and asymmetrical thigh folds, with possible femoral head dislocation. PFFD typically results in more significant and persistent shortening, which can extend to the mid-tibia or knee of the unaffected limb, or even involve near-total absence of the femur. The affected hip in PFFD is usually flexed, abducted, and externally rotated. Etiological factors like diabetes, drug exposure, viral infections, and trauma, noted in the literature, were absent in this case. PFFD may present as isolated, with associated facial anomalies, or affect multiple limb segments. Management is individualized and may involve prosthesis, pelvic-femoral osteotomies, Van Nes rotationplasty, femoral derotation and valgus osteotomy, or limb lengthening.This case is Type C as per Aitken classification.