Atypical Bilateral Proximal Femoral Focal Deficiency: A Case Report and Review of Literature

Proximal femoral focal deficiency (PFFD) is a rare congenital skeletal abnormality with an incidence of 1 per 100,000 births. It is typically a unilateral abnormality but can present bilaterally in 15% of PFFD cases. It is characterized by the absence of the proximal femur and shortening of the affected limb henceforth. It is associated with other skeletal anomalies, and its radiographic appearance continues to progress with age. Treatment options vary widely from conservative approaches to surgical correction and stabilization. This report presents a case description and a review of diagnostic and management approaches.

A 2-year-old girl presented with abnormal crawling, standing, and walking postures. On physical examination, the patient had unusual short bulky thighs with an apparent limb length discrepancy of 2.5 cm and the hips positioned in flexion, abduction, and external rotation, with bilateral knee flexion contractures. Radiographs showed focal deficiency of the proximal femurs bilaterally and shortening. MRI revealed bilateral severely dysplastic acetabula with dislocation of bilateral femurs and formation of pseudoacetabula. PFFD on the right is consistent with Aitken C (absent femoral head) and on the left with Aitken B (femoral head present but without an osseous connection between the head and shaft).

Bilateral PFFD is a rare entity that is associated with a myriad of difficulties. It is crucial to acknowledge the importance of imaging-based diagnosis and individualized management tailored to imaging findings, possibly even within the same patient with bilateral asymmetric PFFD. A multidisciplinary approach is needed to discuss the treatment options available, aiming to restore a functional limb of adequate length and maintain quality of life.