Slipped Upper Femoral Epiphysis (SUFE)

Slipped upper femoral epiphysis (SUFE, or slipped capital femoral epiphysis, SCFE) is displacement of the femoral head epiphysis through the growth plate in adolescence, and it needs same-day orthopaedic referral.

It typically presents at 10 to 16 years, during the growth spurt. Obesity is the main risk factor, and boys are affected slightly more often than girls. Diagnosis is often delayed, and a longer delay means a worse slip.

Knee or thigh pain referred from the hip is the classic cause of a missed diagnosis. Once SUFE is suspected, the child stops weight-bearing.

The physis fails through its hypertrophic zone, which is widest and weakest during the growth spurt. The epiphysis slips posteriorly and inferiorly and stays in the acetabulum, while the neck rotates anteriorly and externally. That is why the hip rolls into external rotation as it is flexed.

Risk factors:

• •Obesity, which increases shear across the physis
• •The adolescent growth spurt, before sex hormones close the physis
• •Femoral retroversion
• •Endocrine and renal disease (hypothyroidism, growth hormone treatment, hypogonadism, renal osteodystrophy), which are uncommon causes

Loder stability is the most useful classification because it predicts avascular necrosis (AVN):

• •Stable: the child can walk, with or without crutches; AVN is uncommon
• •Unstable: the child cannot walk even with crutches; AVN risk is much higher

Severity is graded on the lateral radiograph by slip angle: mild under 30°, moderate 30° to 50°, severe over 50°.