Slipped Capital Femoral Epiphysis and Legg-Calvé-Perthes Disease are easy to mix up on the boards. Here's a side-by-side comparison — presentation, workup, imaging, and first-line treatment — drawn from our full outlines.
Slipped Capital Femoral Epiphysis vs Legg-Calvé-Perthes Disease at a glance
Slipped Capital Femoral Epiphysis: Posterior and inferior displacement of the femoral epiphysis on the metaphysis in adolescents.
Legg-Calvé-Perthes Disease: Idiopathic avascular necrosis of the proximal femoral epiphysis in children aged 4-8.
Try two board-style questions on Slipped Capital Femoral Epiphysis vs Legg-Calvé-Perthes Disease
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Question 1MusculoskeletalMedium
A 9-year-old boy has hip pain and a limp. He is overweight and has limited internal rotation of the hip. Radiograph shows posterior displacement of the femoral head relative to the neck. Which of the following is the most appropriate management?
ASpica cast immobilization
BUrgent surgical pinning
CReassurance and stretching
DImmediate hip aspiration
Reveal answer & full explanation
Correct answer: B — Urgent surgical pinning
ASpica cast immobilization
BUrgent surgical pinning✓
CReassurance and stretching
DImmediate hip aspiration
Why Urgent surgical pinning is correct
An overweight child or adolescent with hip pain, a limp, restricted internal rotation, and posterior epiphyseal slip on x-ray has slipped capital femoral epiphysis.
Treatment is prompt non-weight-bearing and in-situ screw fixation to stabilize the physis.
Delay raises the risk of avascular necrosis and worsening deformity.
Why the others are wrong
Reassurance and stretching — SCFE is a surgical emergency, not benign growing pains; watchful waiting allows the slip to progress.
Spica cast immobilization — Casting does not stabilize a slipped physis and was abandoned for SCFE because of chondrolysis and progressive slip; in-situ fixation is the standard.
Immediate hip aspiration — Aspiration is for suspected septic arthritis, but the radiograph already shows a physeal slip, not a joint infection.
Question 2MusculoskeletalMedium
A 5-year-old boy is brought in for a 6-week history of a painless limp and intermittent right thigh and knee discomfort, without any fever or preceding injury. On exam he has an antalgic gait, mild thigh atrophy, and notably decreased abduction and internal rotation of the right hip. He is afebrile and well-appearing. CBC, ESR, and CRP are normal. AP and frog-leg lateral pelvic radiographs show increased density and a subchondral crescent in the right capital femoral epiphysis; lateral pillar height is fully preserved. Which of the following is the most appropriate initial management?
AFemoral varus derotation osteotomy with internal fixation
BHip spica casting in abduction with radiographic monitoring
COpen reduction and internal fixation of the femoral epiphysis
DActivity restriction and physical therapy for hip mobility
Reveal answer & full explanation
Correct answer: D — Activity restriction and physical therapy for hip mobility
AFemoral varus derotation osteotomy with internal fixation
BHip spica casting in abduction with radiographic monitoring
COpen reduction and internal fixation of the femoral epiphysis
DActivity restriction and physical therapy for hip mobility✓
Why Activity restriction and physical therapy for hip mobility is correct
This boy has classic Legg-Calvé-Perthes disease: a young child (4-8 years) with an insidious painless limp, restricted hip abduction and internal rotation, normal inflammatory markers, and a radiographic crescent sign in the capital femoral epiphysis.
First-line management for a child under 6 years with favorable lateral pillar (Herring) A disease is non-operative: activity restriction to unload the femoral head during fragmentation, NSAIDs for pain, and physical therapy to preserve abduction and internal rotation.
The natural history is healing; the goal is to optimize femoral head shape at skeletal maturity, and young children with an intact lateral pillar generally do well without surgery.
Why the others are wrong
Hip spica casting in abduction with radiographic monitoring is a containment strategy, but bracing and casting have largely fallen out of favor and are not the initial step for a young child with the best prognostic profile.
Femoral varus derotation osteotomy with internal fixation is a real surgical containment procedure reserved for older children (>=6-8 years) with lateral pillar B or B/C-border disease, not initial management for a child under 6 with a fully preserved lateral pillar.
Open reduction and internal fixation of the femoral epiphysis describes the treatment of slipped capital femoral epiphysis, which affects older, often obese adolescents (10-16 years) with an externally rotated hip and a displaced epiphysis, not this younger child with avascular changes.
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Posterior and inferior displacement of the femoral epiphysis on the metaphysis in adolescents.
Idiopathic avascular necrosis of the proximal femoral epiphysis in children aged 4-8.
Classic presentation
Obese adolescent with insidious thigh or knee pain, limp, and obligate external rotation of the hip during flexion.; 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); Antalgic…
Young boy aged 4-8 with a painless limp, restricted internal rotation and abduction of the hip, and characteristic crescent sign or femoral head flattening on radiographs.; Insidious, painless or mildly painful limp; Hip, groin, thigh, or referred knee pain; Decreased activity tolerance; Symptoms typically persist over weeks to months…
Workup / key labs
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.; TSH, growth hormone studies if presentation is atypical (age <10 or >16, short stature, bilateral)…
Lateral pillar (Herring) classification at the fragmentation stage assesses the height of the lateral one-third of the epiphysis: A — full height preserved (best prognosis); B — at least 50 percent of original height; B/C border — exactly 50 percent or narrow lateral pillar; C — less than 50 percent of height (worst prognosis). Age at…
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…
AP and frog-leg lateral pelvic radiographs; Early findings: increased epiphyseal density, joint space widening, crescent sign (subchondral fracture); Later findings: epiphyseal fragmentation, flattening, lateral extrusion of the femoral head; MRI for early disease before radiographic changes appear
First-line treatment
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…
Activity restriction to limit hip joint loading and protect the femoral head during fragmentation; NSAIDs for pain; Physical therapy emphasizing hip range of motion (abduction and internal rotation); Crutches or partial weight bearing for symptomatic relief; Observation alone for children <6 years with lateral pillar A or B disease
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