Slipped Capital Femoral Epiphysis

Often atraumatic or associated with a minor injury, slipped capital femoral epiphysis (SCFE) - also known as slipped upper femoral epiphysis - is one of the most common adolescent hip disorders and represents a unique type of instability of the proximal femoral growth plate. Four separate clinical groups are seen:

    • Pre-slip: wide epiphyseal line without slippage.

    • Acute form: slippage occurs suddenly, normally spontaneously.

    • Acute-on-chronic: slippage occurs acutely where there is already existing chronic slip.

    • Chronic: steadily progressive slippage (the most common form).

The condition is also categorised as:

    • Stable (90% of cases): the patient is able to walk.[1]

    • Unstable (10% of cases): the patient is unable to walk (even with crutches).

Diagnosis is often delayed - and this is associated with a worse prognosis.[2] Although surgery remains the standard treatment, the management of SCFE remains controversial - a Cochrane review is currently assessing the outcome of surgical and non-operative treatments.[3]

Epidemiology

    • The incidence is 10/100,000 children per year.[4]

    • Most commonly it occurs in boys of 10-17 years of age. Peak age is 13 years for boys and 11.5 years for girls.

    • It is the most common hip disorder in adolescents.

    • The left hip is more commonly affected than the right; it is bilateral in 20-40% of cases.

    • It is three times as common in boys.[5]

Risk factors

    • Mechanical: local trauma, obesity.

    • Inflammatory conditions: neglected septic arthritis.

    • Hypothyroidism, hypopituitarism, growth hormone deficiency, pseudohypoparathyroidism, vitamin D deficiency.

    • Previous radiation of the pelvis, chemotherapy, renal osteodystrophy-induced bone dysplasia.

Presentation

    • Discomfort in the hip, groin, medial thigh or knee (knee pain is referred from the hip joint) during walking; pain is accentuated by running, jumping, or pivoting activities.

    • Pre-slip: slight discomfort.

    • Acute:

        • Severe pain such that the child is unable to walk or stand.

        • Alterations in gait, including a limp on the affected side, external rotation of the leg, and trunk shift.

        • Hip motion is limited, especially internal rotation and abduction, due to pain.

    • Acute-on-chronic: pain, limp and altered gait occurring for several months, suddenly becoming very painful.

    • Chronic:

        • Mild symptoms with the child able to walk with altered gait. In a significant number of cases knee pain is reported as the only symptom.

        • External rotation of the leg during walking. Range of motion of the hip shows reduced internal rotation with additional external rotation.

        • When flexed up, the hip tends to move in an externally rotated position.

        • Mild-to-moderate shortening of the affected leg.

        • Atrophy of the thigh muscle may be noted.

Differential diagnosis

Other causes of hip pain - for example:

Investigations

Anteroposterior and 'frog-leg' lateral X-rays show widening of epiphyseal line or displacement of the femoral head.

    • Earliest findings include globular swelling of the joint capsule, irregular widening of the epiphyseal line and decalcification of the epiphyseal border of the metaphysis.

    • Epiphysis normally extends slightly cephalad to the upper border of the femoral neck.

    • Small amounts of slippage can be detected by the epiphyseal edge becoming flush with the superior border of the neck.

    • Sometimes, however, the only evidence of epiphyseal injury is slight widening of the growth plate.

Associated diseases

Associated injuries are common with slipped capital femoral epiphysis; patients should be evaluated for possible pelvic fractures.

Management

    • Avoid moving or rotating the leg. The patient should not be allowed to walk.

    • Provide analgesia and immediate orthopaedic referral if the diagnosis is suspected.

    • The patient should be scheduled for surgery immediately.

    • Surgical closure of the epiphysis, usually by inserting screws percutaneously.[6]

    • Corrective osteotomy is usually reserved for treatment of severe deformities after the patient has stopped growing.

Complications

    • Chondrolysis (degeneration of the articular cartilage), avascular necrosis of the epiphysis, and long-term effects of altered femoral head anatomy.

    • Chondrolysis is seen in 5-8% of slips, and is associated with specific risk factors: African-American race, female gender, screw penetration of articular cartilage, body cast immobilisation, femoral neck osteotomy, and severe slips.

    • Avascular necrosis of the epiphysis occurs in 10-25% of cases, and is associated with attempts to reduce a displaced epiphysis before treatment and with osteotomy of the femoral neck.[7]

Prognosis

    • The prognosis depends on the initial degree of epiphyseal slippage and prompt recognition by the general practitioner.

    • The end result is good to excellent in 94-96% of cases if fragments are displaced by less than one third of the diameter of the femoral neck.

    • With increasing displacement, complications increase and up to 45% of patients have a fair-to-poor surgical result.

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Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions.