Slipped capital femoral epiphysis

Slipped capital femoral epiphysis (SCFE or skiffy, slipped upper femoral epiphysis, SUFE or , coxa vara adolescentium) is a medical term referring to a fracture through the growth plate (physis), which results in slippage of the overlying end of the femur (metaphysis). Normally, the head of the femur, called the capital, should sit squarely on the femoral neck. Abnormal movement along the growth plate results in the slip. The term slipped capital femoral epiphysis is actually a misnomer, because the epiphysis (end part of a bone) remains in its normal anatomical position in the acetabulum (hip socket) due to the ligamentum teres femoris. It is actually the metaphysis (neck part of a bone) which slips in an anterior direction with external rotation. SCFE is the most common hip disorder in adolescence. SCFEs usually cause groin pain on the affected side, but sometimes cause knee or thigh pain. One in five cases involves both hips, resulting in pain on both sides of the body. SCFEs occurs slightly more commonly in adolescent males, especially young black males, although it also affects females. Whilst it can occur in any child, the major risk factor is childhood obesity. Symptoms include the gradual, progressive onset of thigh or knee pain with a painful limp. Hip motion will be limited, particularly internal rotation. Running, and other strenuous activity on legs, will also cause the hips to abnormally move due to the condition and can potentially worsen the pain. Stretching is very limited.

Usually, a SCFE causes groin pain, but it may cause pain in only the thigh or knee, because the pain may be referred along the distribution of the obturator nerve. In cases of bilateral SCFEs, they typically occur within one year of each other. Signs of a SCFE include a waddling gait, decreased range of motion. Often the range of motion in the hip is restricted in internal rotation, abduction, and flexion. Obesity is the by far the most significant risk factor. A study in Scotland looked at the weight of 600,000 infants, and followed them up to see who got SCFE. Sometimes no single cause accounts for SCFE, and several factors play a role in the development of a SCFE i. e. both mechanical and endocrine (hormone related) factors. Skeletal changes may also make someone at risk of SCFE, including femoral or acetabular retroversion,

An intrinsic weakness in the physis with a high axial load is the hypothesized mechanism. Obesity is the most important predisposing factor in the development of SCFE (working by increasing axial load). The physis being more vertical and weak, perichondrial ring being thin and unlocking of interlocking mamillary processes in adolescence contributes to high incidence. The condition is also more common in boys. The fracture occurs at the hypertrophic zone of the physeal cartilage. Stress on the hip causes the epiphysis to move posteriorly and medially, relative to the metaphysis. Although it is not the epiphysis that displaced, by convention, position and alignment in SCFE is described by referring to the relationship of the proximal fragment (capital femoral epiphysis) to the normal distal fragment (femoral neck). Because the physis has yet to close, the blood supply to the epiphysis still should be derived from the femoral neck; however, this late in childhood, the supply is tenuous and frequently lost after the fracture occurs. Manipulation of the fracture (as in an attempted reduction, especially a forceful one) frequently results in osteonecrosis and the acute loss of articular cartilage (chondrolysis) because of the tenuous nature of the blood supply.

The diagnosis is a combination of clinical suspicion plus radiological investigation. Children with a SCFE experience a decrease in their range of motion, and are often unable to complete hip flexion or fully rotate the hip inward. 20–50% of SCFE are missed or misdiagnosed on their first presentation to a medical facility. SCFEs may be initially overlooked, because the first symptom is knee pain, referred from the hip. The knee is investigated and found to be normal. The appearance of the head of the femur in relation to the shaft likens that of a "melting ice cream cone", visible with Klein's line. The severity of the disease can be measured using the Southwick angle.

SCFE affects approximately 1–10 per 100,000 children. Africans and Polynesians have higher rates of SCFE. and affects boys more frequently than girls (male 2:1 female). Other risk factors include: family history, endocrine disorders, radiation / chemotherapy, and mild trauma. The left hip is more often affected than the right. Over half of cases may have involvement on both sides (bilateral).