Unilateral short femur--what does this mean? Report of 3 cases.

Objectives: This study aims to: (1) characterize the prenatal diagnosis of short femur; (2) describe typical findings of proximal focal femoral deficiency; and (3) review the most common differential diagnoses for short femur(s).

Methods: We present 3 examples of prenatally diagnosed proximal focal femoral deficiency and briefly reviewed the differential diagnosis of short femur(s) in utero and associations such as ethnic variation, trisomy 21, and diabetic embryopathy.

Results: Multiple cases are presented in which a short femur (unilateral or bilateral) is the dominant finding on prenatal ultrasound. The fetuses were extensively examined for other skeletal anomalies, and global skeletal dysplasias are excluded from the differential diagnosis. Prenatal imaging findings are correlated with postnatal history and imaging.

Conclusion: Prenatal sonography is now widely used as a screening tool, and at times, subtle findings such as an isolated short femur can be seen without other significant anatomic abnormalities. Counseling for the parents can be difficult without some knowledge of the range of associations seen with short femur(s). Proximal focal femoral dysplasia should be considered in the differential diagnosis when a short femur is discovered.