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Slipped capital femoral epiphysis (SCFE)
In an overweight adolescent with hip, thigh or knee pain, the femoral head slips posteriorly and inferiorly through a weakened growth plate; treatment is urgent in-situ screw fixation, never forceful reduction.
Why it matters in the exam
The classic stem is an overweight child aged 10–16 (boys more than girls) with a limp and knee pain, obligatory external rotation when the hip is flexed (Drehmann sign) and a frog-leg lateral radiograph that shows the slip. The question usually turns on recognising referred knee pain, ordering AP and lateral views of both hips, stopping weight-bearing at once and knowing that an unstable slip carries a high risk of avascular necrosis. An atypical age (younger than 10) or a thin child should prompt a search for an endocrine cause such as hypothyroidism. On examination, loss of internal rotation is the earliest and most consistent finding, and the child often walks with the foot turned outward. Beyond the stable and unstable split, severity is graded by the slip angle on the lateral view as mild, moderate or severe. Advanced questions deal with whether to pin the opposite hip prophylactically, mainly in young children or those with an endocrine disorder, and with late complications such as chondrolysis, impingement between the femoral neck and the acetabular rim, and early joint wear in adult life. The key exam message is that every delay in diagnosis lets the slip progress and worsens the outcome, so knee pain in an adolescent always calls for a hip examination.
Key points
- Overweight adolescent with a limp and knee or thigh pain — think SCFE.
- Drehmann sign: the hip rolls into external rotation during passive flexion.
- Klein line and the lateral view confirm the diagnosis; always image both hips.
- Stable means able to bear weight; unstable means unable, with a high AVN risk.
- Treatment: stop weight-bearing, then in-situ screw fixation.
Summary table
| Feature | Stable slip | Unstable slip |
|---|---|---|
| Definition (Loder) | The child can bear weight, with or without crutches | The child cannot bear weight even with crutches |
| Risk of avascular necrosis (AVN) | Low, close to 0% | High, up to about 50% |
| Typical presentation | Weeks to months of dull pain and limp | Sudden severe pain, sometimes after minor trauma |
| Treatment | Single cannulated screw in situ, centred in the femoral head | Urgent fixation; gentle positioning only, no forceful reduction |
| Opposite hip | Bilateral in up to 20% at diagnosis and up to 40% over time | Same risk; consider prophylactic pinning in high-risk patients |
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Sources
- Lovell and Winter's Pediatric Orthopaedics, 8th ed. (2020) — Slipped Capital Femoral Epiphysis
- AAOS Comprehensive Orthopaedic Review, 3rd ed. (2019) — Pediatric Hip Disorders
- Apley and Solomon's System of Orthopaedics and Trauma, 10th ed. (2017) — The Hip
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.