SUFE – Slipped Upper Femoral Epiphysis

Definition:

Slippage of the epiphysis relative to the femoral neck (epiphysis stays in the acetabulum while the neck displaces anteriorly and externally rotates (epiphysis is posterior)

Pathoanatomy:

Due to mechanical forces acting on a susceptible physis. Slippage occurs though the hypertrophic zone of the physis (cartilage in the hypertrophic zone acts as a weak spot).

Epidemiology:

  • Most common disorder affecting adolescent hips (10/100,000)
  • More common in: males (3:2)
  • Obese children (single greatest risk factor), during period of rapid growth             Left hip is more common, bilateral in 17 to 50%
  • Average age: 13.4 for boys, 12.2 for girls
  • Associated factors:
    • Femoral retroversion
    • Obesity
    • Previous radiation therapy to the femoral head region
  • Endocrine disorders (hypothyroidism, osteodystrophy of chronic renal failure, growth hormone treatment)
    • Investigate if child is < 10 years old (Hypothyroidism (elevated TSH), Osteodystrophy of chronic renal failure (abnormal Ur and Cr), GH treatment)

Classification:

  • Stable vs. unstable (Loder classification): Provides prognostic info
    • Stable: Able to WB with or without crutches (<10% risk of osteonecrosis)
    • Unstable: Unable to WB even with crutches (~47% risk of osteonecrosis)
  • Acute:
    • Symptoms <3/52
    • Chronic: symptoms >3/52
    • Acute on chronic: Acute exacerbation on long-standing symptoms
  • Grading system (% of slippage)
    • Grade I: 0 – 33%
    • Grade II: 34 – 50%
    • Grade III: > 50%

Clinical Presentation:

History:

Groin/ thigh pain most common (knee pain in 20%!), symptoms usually weeks – months before Dx made, patients prefer sitting in a chair with affected leg crossed over the other.

Examination:

Antalgic, Trendelenburg or externally rotated gait

External rotation during passive flexion of hip, loss of hip internal rotation, abduction, and thigh atrophy

Investigations:

AP + Frog lateral (Better) radiographs

Epiphyseolysis: Growth plate widening or loosening (EARLY FINDING!)

Klein’s line: line drawn along superior border femoral neck will not intersect femoral head in a child with SCFE (does in a normal hip)

Metaphyseal blanch sign of Steel: Seen on AP, blurring/step off of proximal metaphysis due to overlapping of the metaphysis and the posteriorly displaced epiphysis

MRI: Helps diagnosing a preslip condition when x-ray’s are NAD, shows growth plate widening and increased signal of the metaphysis

Operative treatment:

Percutaneous in-situ fixation:

  • For both stable and unstable slips, stabilises the epiphysis from further slippage & promotes closure of proximal femoral physis.
  • DO NOT FORCEFULLY REDUCE (risk of AVN!)
  • Position on traction table
  • SINGLE CANNULATED SCREW (multiple pins = ↑AVN)
  • Screw entry point will be on the anterior surface of the neck in order to cross perpendicular to the physis
  • Enter the central portion of the femoral head (which has slipped posteriorly) on both AP + lateral
  • Minimum 4 threads crossing the physis, screw should be >5mm from subchondral bone in all views
  • Postop: Stable slips can WB, unstable slips remain NWB

Controlled reduction & fixation:

  • Modified Dunn procedure with formation of epiphyseal vascular flap
  • Controversial, for unstable, high grade SUFE’s

Proximal femoral osteotomy:

  • Indicated in severe, chronic slip
  • Can be performed in subcapital, femoral neck (both provide best correction BUT ↑AVN), intertrochanteric and subtrochanteric regions

Controversies:

  1. One vs. two cannulated screws
  2. Reduction of epiphysis
  3. Capsulotomy (to reduce pressure)
  4. Prophylactic pinning of un-slipped opposite slip in all patients

Complications:

  1. AVN of femoral head (most common), ↑ with unstable slip (47%) and posteriosuperior femoral neck placement
  2. Chondrolysis: 20 to unrecognised screw penetration of the articular surface
  3. Limb length discrepancy
  4. Slip progression (1-2% following single screw fixation)
  5. Hip stiffness
  6. Degenerative OA
  7. Stress

Join our question bank for instant access to questions and tips to prepare you for the ST3 Ortho Interview!

 Clinical Questions

Leave a Reply