SCFE (Slipped Capital Femoral Epiphysis)

Key Points:


Traditionally slipped capital femoral epiphysis (SCFE) has been described as posterior and medial slippage of the capital femoral epiphysis with respect to the metaphysis. However, the epiphysis is held in the acetabulum by the ligamentum teres; thus, the metaphysis actually moves laterally and anteriorly in relation to the epiphysis.

In most patients, SCFE results in varus alignment. Valgus slips are uncommon and may be associated with underlying endocrinopathies (Shank 2010).


The prevalence of SCFE in the U.S. ranges from 2 to 11 per 100,000 (Loder, 1996). African Americans, males, and obese children are more frequently affected. The typical age groups are 12-15 years in boys and 11-14 years in girls. Juvenile onset (age less than 10 years) should raise the suspicion of an underlying endocrinopathy. 

Atypical slips may be seen in patients with endocrine abnormalities (hypothyroidism, hypopituitarism, acromegaly as well as growth hormone supplementation, hyperparathyroidism), kidney disease and those who have received radiation treatment (Loder, 2001). 

Mechanical factors implicated in the development of SCFE include relative retroversion of the femur, deep set acetabulae, increased physeal slope and obesity (Pritchett, 1988; Mirkopulos, 1988).

Roughly one third (18-50%) of cases may show bilateral involvement either at presentation or within the next 18-24 months (Loder, 1993). Various factors have been used to predict the risk of contralateral slip (Riad, 2007; Zide, 2011).

Clinical Findings:

Hip, thigh or knee pain and limp are common presenting symptoms. Progressive external foot progression may be noted. A history of radiation, renal disease, thyroid or other endocrine disorders including growth hormone treatment may be present in the setting of non-idiopathic slip. 

On exam, in a typical varus SCFE, there is increased hip external rotation and limited flexion, abduction, internal rotation. In some instances there is obligate external rotation with flexion of the affected side (Drehmann sign). The affected extremity may be shorter in a unilateral slip, and a Trendelenberg sign may be present. Clinically, a slip is deemed stable if the patient is able to bear weight on the affected side, even with assistive devices (Loder, 1993). This is of prognostic significance as the rate of avascular necrosis (AVN) is higher (20-60%) in the unstable slips, and negligible in stable hips. 

Imaging Studies:


Bone scan: May be used to assess vascularity of the head

CT scan: Not typically indicated in diagnosis of SCFE, but may be useful in preoperative planning for complex reconstruction, such as prior to multi-planar Southwick osteotomy 



The gold standard treatment of SCFE remains in situ screw fixation (especially for mild to moderate slips), although some centers have adopted more aggressive approaches (closed manipulation or mini-open reduction before fixation or the modified Dunn procedure) that improve capital alignment so as to minimize potential damage to the articular cartilage and labrum due to a non-concentric joint. 

Stable Slip

In situ screw fixation is the recommended treatment for a stable slip, and is  performed percutaneously under fluoroscopic guidance. Attempting to reduce or manipulate a stable slip may result in physeal or vascular damage and increase the risk of AVN. The patient is positioned on a fracture table with the affected hip in neutral position, with patella forward. There is no attempt at intentional reduction. The unaffected limb is flexed and abducted out of the way. Fluoroscopy is brought in prior to draping to ensure appropriate positioning of the image intensifier. Many surgeons prefer a double fluoroscopy machine technique to avoid moving the fluoroscopy machine between the AP and lateral imaging positions. Pinning on a flat Jackson table is an alternate technique, but results in more difficult imaging and the potential for bending the guide wire as the affected limb must be moved in and out of the frog lateral position. The starting point of the screw is usually anterolateral on the neck and should be proximal to the lesser trochanter (to minimize risk of fracture) and distal to the intertrochanteric line (to avoid iatrogenic screw head impingement). The screw should preferably be perpendicular to the physis on AP and lateral views and should be directed towards the center of the epiphysis to minimize risk of inadvertent joint penetration. The screw tip should be left 5 mm short of the sub-chondral bone. Five threads should cross the physis (Carney 2003). 

Unstable Slip

For an unstable slip, inadvertent reduction with patient positioning may occur, or a mini-open reduction may be accomplished using an anterior approach with digital reduction (to the point of correction of the acute deformity) and fixation with K wires (Parsch, 2009) or screws. Fixation with 2 screws it typical in the treatment of unstable slips to avoid spinning the epiphysis as the screw is inserted.  Decompression of the capsule to minimize the risk of AVN in unstable slip is a consideration (Schrader 2016). This may be performed with a Cobb elevator directed up the femoral neck to disrupt the capsule, or through direct approach to the hip. The modified Dunn procedure via a surgical hip dislocation approach (Slongo, 2010) is another option for an unstable slip, but is  recommended with caution as there are significant complications associated with the procedure including hardware failure (15%) and AVN (26%) (Sankar, 2013). The modified Dunn should be limited to acute, unstable, severe slips (greater than 50-degree slip angle), done within 24 hours by an experienced surgeon (Upasani, 2014). 

Prophylactic Pinning 

There is a 10-30% risk of a subsequent contralateral slip in patients presenting with a unilateral slip. Most of the subsequent slips are mild. The risk varies by age, skeletal maturity (modified Oxford score), and underlying disorders. Subsequent contralateral slip is highest in untreated renal disease, endocrinopathies, and patients with a history of radiation. Prophylactic pinning is recommended in these situations. Prophylactic pinning may also be considered in patients suspected to be non-compliant with follow up, as well as younger patients (girls less than 10 years, boys less than 12 years, modified oxford score of 16 or less), and those  with posterior sloping angle (PSA) more than 15-18 degrees on the unaffected side. (Barrios, 2005; Phillips, 2013)


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Top Contributors:

Mihir Thacker, MD