Slipped Capital Femoral Epiphysis (SCFE)

Modern Study Review (AI-Generated)

High-Yield Summary

Slipped Capital Femoral Epiphysis (SCFE) is a critical adolescent hip disorder characterized by displacement of the femoral head relative to the femoral neck through the growth plate. It predominantly affects children during rapid growth spurts, with a higher incidence in obese patients and those with endocrine abnormalities. Early diagnosis and stabilization are essential to prevent long-term complications such as avascular necrosis (AVN) and chondrolysis, which significantly impact pain and hip function.

Key Diagnostic Findings

Anatomy

Physis (Growth Plate): Weakest point in the proximal femur during adolescence, allowing the epiphysis to slip posteriorly and inferiorly relative to the metaphysis.
Femoral Head and Neck: Displacement occurs through the hypertrophic zone of the physis.

Clinical Presentation

Age: Typically 11-13 years in girls, 13-15 years in boys (growth spurt period).
Symptoms: Progressive hip, groin, or knee pain with limp.
Physical Exam:
Obligatory external rotation of the hip on flexion (pathognomonic).
Decreased internal rotation and abduction.
Ability to bear weight differentiates stable vs unstable slips.

Imaging

Imaging Modality	Key Findings
AP Pelvis X-ray	Klein’s line: a line along the superior femoral neck should intersect the epiphysis; in SCFE, it does not (Trethowan sign). Increased metaphyseal density due to superimposition of the epiphysis.
Frog-leg lateral X-ray	Southwick angle: normal ~10°, increased in SCFE proportional to slip severity.
Bone Scan (Selective)	Used in severe slips to assess femoral head vascularity before reduction.
CT Scan	Used postoperatively to assess physeal closure and screw position if AVN suspected.

Classification Systems

Classification	Description	Clinical Relevance
Stability (Loder Classification)	Stable: patient can bear weight (with or without crutches). Unstable: unable to bear weight.	Unstable slips have higher risk of AVN and require urgent treatment.
Chronicity	Acute (<3 weeks), Chronic (>3 weeks), Acute-on-chronic	Guides urgency and treatment approach.
Southwick Angle	Measures slip severity: <30° mild, 30-50° moderate, >50° severe	Influences surgical planning.

Current Gold Standard Treatment

Non-operative

Limited role: Bed rest and non-weight bearing only as temporizing measures in stable slips before surgery.
No role for prolonged conservative management due to risk of slip progression and complications.

Operative Indications and Treatment

Indication	Treatment
Stable SCFE	In situ single screw fixation across the physis to prevent further slip.
Unstable SCFE	Urgent in situ fixation; gentle reduction only if severe displacement and after vascularity assessment.
Bilateral or Endocrine Abnormalities	Prophylactic pinning of contralateral hip recommended due to high risk of slip.
Severe Displacement	Bone scan to assess AVN risk; gentle closed reduction may be attempted prior to fixation.

– Surgical Technique: Single cannulated screw fixation is the gold standard, minimizing physeal damage while stabilizing the slip.

Modern Complications & Outcomes

Complications

Complication	Description	Risk Factors	Management
Avascular Necrosis (AVN)	Loss of femoral head blood supply leading to collapse	Unstable slips, aggressive reduction, delayed fixation	Early diagnosis, screw removal if near joint, possible bone peg epiphyseodesis
Chondrolysis	Rapid cartilage loss causing joint stiffness and pain	Unknown etiology, possibly related to fixation or inflammation	Symptomatic management, physical therapy
Slip Progression	Further displacement if untreated or unstable	Delayed diagnosis, inadequate fixation	Prompt surgical stabilization
Physeal Closure Issues	Premature or delayed closure affecting growth	Surgical technique, severity of slip	Monitored with imaging, may require revision

Outcomes

Early diagnosis and in situ fixation yield excellent pain relief and functional outcomes.
Unstable slips have worse prognosis due to higher AVN rates.
Prophylactic contralateral pinning reduces risk of bilateral slips in high-risk patients.
Long-term follow-up is essential to monitor for deformity, leg length discrepancy, and early osteoarthritis.

Classic Clinical Notes

Approach to Slipped Capital Femoral Epiphysis

There is a narrow window when this happens—just in the growth spurt area (11-13 in girls, 13-15 in boys).
May be related to endocrine abnormalities: hypothyroid, hypopituitarism, hypogonadism, increased growth hormone; also seen in FAT kids.
The key physical finding is an obligatory external rotation of the hip when flexing.

Defined based on if the kid can walk on it or not (stable or unstable); chronic slips tend to be stable; acute slips tend to be unstable. Note that the stable ones can acutely become UNstable—therefore, if the kid arrives in emerg, walking, with a stable slip, he gets immediate BEDREST and an OR as soon as can be arranged. He DOES NOT GET DISCHARGED HOME ON CRUTCHES.

Southwick’s Femoral head – shaft angle: measured on the frog lateral. Should be 10°; increased in slips.
Klein’s line – a line drawn along the superior border of the neck should pass through part of the epiphysis in the normal hip on an AP pelvis. In slips it misses the epiphysis superiorly. (also called Trethowan sign)
Look for increased metaphyseal density on the AP (superimposition of the head behind the metaphysis).

Treatment

Single pin fixation.
Kids with endocrine abnormalities get prophylactic pinning of the other side; this is the only indication for prophylaxis.
The hugely displaced slips should probably have a bone scan to document avascularity of the head, then a GENTLE closed reduction maneuver (according to Morrissey) prior to fixation.

Beware AVN and chondrolysis—these are the two main complications; they generally do not occur in untreated slips.

What happens when their head collapses from AVN?

Rule out sepsis (clinically, bloodwork).
Then, assess where the screw is—Is it in, or nearing the joint surface? Then you need to consider taking it out.
Then decide, What about the physis—has it closed yet? Get a CT scan to see if the physis has fused yet. If it has, you are safe to take the screw out. If it has not fused, you can do one of two things:

Revise the screw to a shorter screw and hope that the thing will heal before the progressive collapse reveals the screw tip to the joint.
Do an open bone peg epiphyseodesis.

What about ruling out “endocrine abnormalities”?

The obese boys who get this when they’re 14 are probably okay.
But any boy…

Last Updated on January 25, 2026 by orthonet