AANP Family Nurse Practitioner (FNP) Certification ExamDiagnosisMedium
A 6-year-old child is brought to the clinic by his parents due to a 3-week history of worsening right hip pain, limping, and limited range of motion. The parents state the child has been less active and complains of pain primarily when walking or running. On examination, there is decreased abduction and internal rotation of the right hip. Radiographs of the hip show flattening and fragmentation of the femoral head. What is the most likely diagnosis?
- ADevelopmental Dysplasia of the Hip (DDH)
- BTransient Synovitis of the Hip
- CSlipped Capital Femoral Epiphysis (SCFE)
- DLegg-Calvé-Perthes Disease
Show answer & explanationAnswer & explanation
Correct answer: D. Legg-Calvé-Perthes Disease
The patient's age (4-10 years), male gender, insidious onset of hip pain and limp, restricted hip movements (especially abduction and internal rotation), and classic radiographic findings of flattening and fragmentation of the femoral head are diagnostic for Legg-Calvé-Perthes Disease (LCPD).
Why the other options are wrong
- A. DDH is usually diagnosed in infancy or early childhood, characterized by abnormal hip development and instability, not an avascular necrosis of the femoral head.
- B. Transient synovitis is a common cause of acute hip pain and limp in young children, but it is self-limiting, typically resolves within a week, and radiographs are usually normal or show only joint effusion.
- C. SCFE typically occurs in pre-adolescents/adolescents (10-16 years), often overweight, and radiographs show posterior and inferior displacement of the femoral epiphysis.
Legg-Calvé-Perthes Disease (LCPD)
An idiopathic osteonecrosis (avascular necrosis) of the femoral head in children, leading to flattening and fragmentation of the femoral head.
- Typically affects boys aged 4-10 years.
- Presents with hip pain, limp, and restricted hip abduction/internal rotation.
- Diagnosis confirmed by radiographs showing characteristic changes in the femoral head.
Memory trick: PERTHES: Pain, Early age (4-10), Restricted movement, Trabecular (femoral head) changes, Hip issues, Etiology unknown (idiopathic), Slowly progressive.