Posterior and inferior displacement of the femoral epiphysis on the metaphysis in adolescents.
Also known as: SCFE, slipped capital femoral epiphysis, slipped upper femoral epiphysis, SUFE
Overview
Salter-Harris type I fracture-equivalent injury through the proximal femoral physis, in which the capital femoral epiphysis displaces posteriorly and inferiorly relative to the femoral neck. Occurs during the adolescent growth spurt and is the most common hip disorder of adolescence.
Epidemiology
Incidence approximately 10 per 100,000 children annually in the United States. Peak age 10-15 in girls and 12-16 in boys; males affected 1.5-2 times more often than females. Higher prevalence in Black, Hispanic, and Pacific Islander adolescents. Bilateral involvement in 20-40 percent (synchronous or sequential).
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Question 1MusculoskeletalEasy
A 13-year-old boy with obesity (BMI 32) presents with a 4-week history of left hip and medial knee pain and a new limp. He denies trauma or fever. Exam shows the left leg held in external rotation, and passive hip flexion produces obligate external rotation and abduction. There is no warmth or erythema. Vitals are normal. Which of the following is the most likely diagnosis?
ATransient synovitis of the hip
BDevelopmental dysplasia of the hip
CSlipped capital femoral epiphysis
DLegg-Calve-Perthes disease
Reveal answer & full explanation
Correct answer: C — Slipped capital femoral epiphysis
ATransient synovitis of the hip
BDevelopmental dysplasia of the hip
CSlipped capital femoral epiphysis✓
DLegg-Calve-Perthes disease
Why Slipped capital femoral epiphysis is correct
Slipped capital femoral epiphysis (SCFE) is a Salter-Harris I fracture through the proximal femoral physis, classically seen in obese adolescents aged 10-16
The femoral head slips posteriorly and inferiorly relative to the neck
Patients present with hip, groin, or referred knee pain and a limp, with the affected leg held in external rotation
Obligate external rotation with passive hip flexion (Drehmann sign) is highly suggestive
Diagnosis is confirmed with AP and frog-leg lateral radiographs of both hips
Treatment is urgent in situ percutaneous screw fixation to prevent further slippage and avascular necrosis; the patient should be made non-weight-bearing immediately
Why the others are wrong
Transient synovitis of the hip — typically follows a viral illness in children 3-8 years old and resolves within days; a 4-week course in an obese 13-year-old with obligate external rotation does not fit. Trap: premature closure on the most common cause of pediatric limp
Developmental dysplasia of the hip — diagnosed in infancy with Barlow/Ortolani maneuvers and asymmetric skin folds; it does not present as a new limp in adolescence. Trap: buzzword-matching a familiar pediatric hip diagnosis to any childhood hip complaint
Legg-Calve-Perthes disease — idiopathic avascular necrosis of the femoral head, typically in children 4-8 years old and not associated with obesity. Trap: confused-with-SCFE; both cause an atraumatic limp, but age and body habitus separate them
Question 2MusculoskeletalEasy
A 12-year-old obese boy has insidious right hip and knee pain with a limp for 6 weeks, and now keeps the right leg in external rotation when supine. Frog-leg lateral X-ray shows posteromedial slippage of the femoral epiphysis. Which of the following is the most appropriate next step in management?
AImmobilization in a long-leg cast
BUrgent in situ surgical pinning
CClosed reduction and internal fixation
DProtected weight-bearing with crutches
Reveal answer & full explanation
Correct answer: B — Urgent in situ surgical pinning
AImmobilization in a long-leg cast
BUrgent in situ surgical pinning✓
CClosed reduction and internal fixation
DProtected weight-bearing with crutches
Why Urgent in situ surgical pinning is correct
Slipped capital femoral epiphysis (SCFE) presents in an adolescent, often obese, with hip/knee pain, limp, and obligate external rotation when the hip is flexed
Frog-leg lateral X-ray confirms posteromedial slip of the proximal femoral epiphysis through the physis
Standard of care is urgent in situ percutaneous screw fixation to prevent further slippage and avascular necrosis (the major complication)
The patient should be made non-weight-bearing immediately upon suspicion to avoid worsening the slip
Why the others are wrong
Closed reduction and internal fixation — closed reduction is contraindicated because forceful reduction increases the risk of avascular necrosis (right-concept-wrong-maneuver; pin in situ, do not reduce)
Immobilization in a long-leg cast — casting does not stabilize the physis or prevent further slippage or avascular necrosis (confused-with a fracture-management approach)
Protected weight-bearing with crutches — any weight-bearing still loads the unstable physis and risks progression of the slip; the child is kept strictly non-weight-bearing until urgent in situ fixation
Additional high-yield points
Bilateral SCFE occurs in 20–40% of cases, so the contralateral side may need prophylactic pinning
Knee pain from referred hip pathology is a classic pitfall; always image the hip in an adolescent with a limp
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Obesity (>95th percentile BMI is the strongest risk factor)
Adolescent growth spurt
Male sex
Endocrinopathies — hypothyroidism, growth hormone deficiency or therapy, hypogonadism, panhypopituitarism
Chronic renal failure with renal osteodystrophy
Prior radiation to the pelvis
Family history
Pathophysiology
Mechanical and hormonal factors weaken the proximal femoral physis. Shear forces across the obliquely oriented growth plate cause the epiphysis to remain in the acetabulum while the metaphysis (femoral neck) displaces anteriorly and superiorly — clinically expressed as posterior and inferior slip of the epiphysis. Endocrine dysfunction further weakens the physis, explaining bilateral and atypical presentations.
Clinical presentation
Symptoms
Insidious or acute hip, groin, thigh, or knee pain in an adolescent
Limp
Referred knee pain is classic — examine the hip in any adolescent presenting with knee pain
Inability to bear weight (unstable SCFE)
Signs / physical exam
Antalgic gait with externally rotated lower extremity
Loss of internal rotation of the hip
Obligatory external rotation with passive hip flexion (Drehmann sign)
Leg length discrepancy on the affected side
Classic findings
Obese adolescent with insidious thigh or knee pain, limp, and obligate external rotation of the hip during flexion.
Differential diagnosis
Legg-Calvé-Perthes disease — Younger children (4-8 years), avascular necrosis of the femoral head, painless limp, normal weight
Developmental dysplasia of the hip — Identified in infancy; Ortolani and Barlow maneuvers, asymmetric thigh folds
Septic arthritis of the hip — Fever, refusal to bear weight, elevated ESR/CRP, joint aspiration confirms
Transient synovitis — Recent viral illness, painful limp, afebrile, self-limited; Kocher criteria help distinguish from septic arthritis
Femoral neck fracture — History of significant trauma; radiographs diagnostic
Diagnostic workup
Diagnostic criteria
Loder classification (functional, prognostic): Stable — patient can bear weight with or without crutches; Unstable — cannot bear weight even with crutches. Severity by Southwick angle: mild <30, moderate 30-50, severe >50 degrees of slip.
Labs
TSH, growth hormone studies if presentation is atypical (age <10 or >16, short stature, bilateral) or recurrent
Renal function and PTH in suspected renal osteodystrophy
Imaging
AP and frog-leg lateral radiographs of BOTH hips (synchronous bilateral disease)
Klein line — line drawn along the superior femoral neck on AP view should intersect a portion of the epiphysis; failure to intersect (Trethowan sign) suggests slip
Widened, irregular physis; metaphyseal blanch sign of Steel
MRI for pre-slip or contralateral monitoring
Diagnostic algorithm
Loder Classification
Weight Bearing
AVN Risk
Management
Stable
Able with or without crutches
Low (<5%)
Urgent in situ pinning
Unstable
Unable, even with crutches
High (up to 50%)
Emergent operative stabilization
Loder functional classification of SCFE with associated avascular necrosis risk.
Treatment
First-line
Immediate non-weight bearing and orthopedic referral upon suspicion — NEVER allow continued weight bearing while awaiting evaluation
Surgical in situ pinning with a single cannulated screw across the physis is the standard for stable SCFE
Endocrine workup for atypical presentations
Prophylactic pinning of the contralateral hip considered in young patients (<10 years), endocrinopathies, or radiographically apparent contralateral pre-slip
Second-line / adjunct
Unstable SCFE: urgent operative stabilization (within 24 hours), gentle reduction debated due to AVN risk
Modified Dunn procedure or capital realignment osteotomy for severe slips
Long-term follow-up for AVN, chondrolysis, and femoroacetabular impingement
Complications
Avascular necrosis of the femoral head (the most feared complication; up to 50 percent of unstable SCFE)
Chondrolysis with stiff, painful hip
Femoroacetabular impingement and early osteoarthritis
Leg length discrepancy
Contralateral slip
PANCE pearls
Knee pain in an adolescent demands a hip examination — referred knee pain is a classic presentation of SCFE.
Continued weight bearing on an undiagnosed SCFE can convert a stable slip into an unstable one with substantially higher AVN risk.
Atypical SCFE — outside the usual age window, in a non-obese child, or bilateral at presentation — warrants endocrine workup.
Prophylactic pinning of the contralateral hip is controversial but commonly performed in high-risk patients.
References
POSNA — Pediatric Orthopaedic Society of North America consensus statements on slipped capital femoral epiphysis
AAOS — American Academy of Orthopaedic Surgeons clinical resources on SCFE
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