Slipped capital femoral epiphysis refers to posterior displacement of the femoral head relative to the rest of the femur. The displacement occurs through the growth plate of the upper aspect of the femur.
Patients with a slipped capital femoral epiphysis experience pain and walk with a limp. The pain may be present around the hip, groin, thigh, or knee. The pain and limp may be mild or severe depending upon the duration and degree of slippage.
Children and adolescents with slipped capital femoral epiphysis may be overweight. They walk with a specific gait abnormality termed “Trendelenburg gait” which is caused by relative shortening of the neck of the femur. All children with slipped capital femoral epiphysis have decreased internal rotation of the affected hip, and some have decreased abduction. In severe, acute slips attempted movement of the hip causes pain. In addition to examination of the hip, patients should be evaluated for signs of endocrine disorders including marked obesity, hypogonadism, and signs of kidney failure.
Children suspected of having slipped capital femoral epiphysis will require x-rays of the hips and pelvis in order to confirm the diagnosis. In addition, children with a suspected underlying endocrine cause will require blood testing to assess the thyroid and pituitary glands, and the kidneys.
The exact cause of slipped capital femoral epiphysis is not known. The growth plate at the upper end of the femur can become weakened by hormonal abnormalities and during certain stages of growth. If the stress to the head of the femur is too high due to weight or trauma, then a slip can occur.
The GOAL of treatment is to prevent further slippage of the head of the femur. Patients are placed on bed rest until the hip can be surgically stabilized. A screw is inserted across the growth plate into the epiphysis in order to stabilize the hip. Crutches are used to protect the hip until the growth plate fuses. Patients are x-rayed at regular intervals following surgery. If the degree of slippage is severe, an osteotomy to reorient the upper end of the femur can be performed at a later date.
Complications from slipped capital femoral epiphysis are related directly to the severity and acuity of the slip. The most common complications are avascular necrosis, chondrolysis, and arthritis. Avascular necrosis, present in 30 percent of acute slips, is caused by loss of blood supply and may result in collapse of the femoral head. Chondrolysis, disintegration of the cartilage surface, leads to stiffness and pain. Arthritis usually develops slowly and can be treated by hip fusion or total hip replacement depending upon the patient’s age.