Proximal Femoral Focal Deficiency

Proximal femoral focal deficiency refers to congenital absence or hypoplasia of the proximal femur. It is characterized by a short femur with proximal deficiency and varus deformity of the femoral neck. The Aitken classification divides proximal femoral focal deficiency into four categories. The Amstutz classification subdivides Aitken class A into Amstutz types 1 and 2. Amstutz types 3, 4, and 5 represent Aitken classes B, C, and D, respectively.

• Class A: Short femur with coxa vara. Well-formed acetabulum.
  • Amstutz type 1: Cartilaginous femoral neck.
  • Amstutz type 2: Pseudoarthrosis at the femoral neck.
• Class B: No connection between the femoral head and shaft.
• Class C: Dysplastic acetabulum. Small or absent femoral head not adjoined to the femoral shaft.
• Class D: Both the acetabulum and femoral head are absent.

Case courtesy of Dr. Shilpa Pandey.

References

• Hillmann JS, Mesgarzadeh M, Revesz G, Bonakdarpour A, Clancy M, Betz RR. Proximal femoral focal deficiency: radiologic analysis of 49 cases. Radiology. 1987 Dec;165(3):769-73.
• Maldjian C, Patel TY, Klein RM, Smith RC. Efficacy of MRI in classifying proximal focal femoral deficiency. Skeletal Radiol. 2007 Mar;36(3):215-20.