Musculoskeletal · Pediatric Orthopedics
The facts most likely to be tested
Slipped Capital Femoral Epiphysis (SCFE) typically presents in obese adolescent males during the pubertal growth spurt.
Patients classically present with referred pain to the knee or thigh and a limp despite the pathology being in the hip.
Physical examination reveals a limited internal rotation of the hip and an obligatory external rotation when the hip is flexed.
The gold standard diagnostic imaging is a frog-leg lateral radiograph of the pelvis, which demonstrates posterior and inferior displacement of the femoral head.
Klein’s line is the diagnostic landmark, where a line drawn along the superior border of the femoral neck fails to intersect the epiphysis.
Urgent surgical stabilization with in-situ percutaneous pinning is the definitive treatment to prevent further slippage and complications.
The most feared and serious complication of SCFE is avascular necrosis (AVN) of the femoral head and chondrolysis.
Vignette unlocked
A 13-year-old male with a BMI in the 98th percentile presents to the clinic complaining of a 3-week history of intermittent right knee pain and a persistent limp. He denies any history of trauma. On physical examination, he has decreased internal rotation of the right hip, and passive flexion of the hip results in obligatory external rotation. The knee examination is unremarkable with no swelling or tenderness. A frog-leg lateral radiograph of the pelvis is ordered.
What is the most appropriate next step in management?
Urgent surgical stabilization with in-situ percutaneous pinning
The patient's presentation of knee pain and limited internal rotation in an obese adolescent is classic for SCFE; immediate surgical fixation is required to prevent further displacement and the risk of avascular necrosis.
Full handout
High yield triage
Etiology / Epidemiology
Occurs in obese adolescents during the pubertal growth spurt due to mechanical stress on the physis.
Clinical Manifestations
Presents as hip/knee pain with an antalgic gait and obligatory external rotation of the hip during flexion.
Diagnosis
Frog-leg lateral hip radiograph is the diagnostic gold standard showing ice cream slipping off the cone.
Treatment
Surgical pinning (in situ fixation) is the definitive treatment; avoid weight-bearing immediately upon suspicion.
Prognosis
Risk of avascular necrosis and chondrolysis; requires long-term orthopedic follow-up.
Full handout
Epidemiology & Etiology
Most common hip disorder in adolescents (ages 10–16). Strongly associated with obesity and endocrine disorders like hypothyroidism or hypogonadism. Males are affected more frequently than females.
Pertinent Anatomy
The femoral head displaces posteriorly and inferiorly relative to the femoral neck through the proximal femoral physis. The epiphyseal plate becomes weakened during rapid growth, allowing for shear-force displacement.
Pathophysiology
Increased mechanical load on a weakened growth plate leads to displacement. The physis is susceptible to hormonal changes during puberty, specifically the interaction between growth hormone and sex steroids. This results in a chronic or acute-on-chronic slippage of the epiphysis.
Clinical Manifestations
Patients present with hip, thigh, or knee pain and a limp. Physical exam reveals limited internal rotation and obligatory external rotation when the hip is flexed. Inability to bear weight suggests an unstable slip, which is a surgical emergency.
Diagnosis
Order AP and frog-leg lateral radiographs of both hips. The ice cream slipping off the cone sign is pathognomonic. A Klein line that fails to intersect the epiphysis confirms the diagnosis.
Treatment
Immediate non-weight bearing status is mandatory to prevent further slippage. In situ percutaneous pinning is the standard of care. Do not attempt closed reduction as this significantly increases the risk of avascular necrosis.
Prognosis
Major complications include avascular necrosis and chondrolysis. Patients require long-term monitoring for the development of early-onset osteoarthritis and potential involvement of the contralateral hip.
Differential Diagnosis
Legg-Calvé-Perthes disease: younger age (4-8 years) and idiopathic avascular necrosis
Septic arthritis: acute onset with fever and elevated inflammatory markers
Transient synovitis: follows viral illness with normal inflammatory markers
Developmental dysplasia of the hip: usually presents in infancy
Femoral neck fracture: history of significant trauma