Slipped capital femoral epiphysis (SCFE) is a common hip disorder in adolescents causing slippage or separation of the femoral head (ball at the upper end of the femur bone) from the weakened epiphyseal growth plate (growing end of the bone). This condition often develops during the rapid growth period after the onset of puberty, and may affect one or both legs at a time. The separation may be caused by an injury or other factors such as obesity and hormonal imbalances. SCFE commonly occurs in children between 11 and 15 years and boys are more likely to develop the condition than girls.
The exact cause of SCFE remains unclear; however, the presence of certain factors may increase the risk of your child developing this condition. These include:
- Obesity: SCFE is more common in children who are obese and have rapid growth. This may be attributed to excess pressure on the growth plate.
- Endocrine disorders such as diabetes, thyroid disease and growth hormone abnormalities (acromegaly)
- Kidney diseases
- Radiation therapy or chemotherapy for childhood leukaemia
- Steroid medications
- Family history of the disorder
Types of SCFE
SCFE is classified into two types, stable and unstable SCFE, based on the severity of pain and damage.
- Stable SCFE (mild slip): The condition is considered mild or stable if the child is having pain or stiffness in the knee or groin area but can manage to walk and may limp. Symptoms worsen with activity and subside with rest. In stable SCFE the child is able to walk with or without the help of crutches.
- Unstable SCFE (severe slip): Any major blow such as a fall or sports injury may cause unstable SCFE. The child may have severe pain and stiffness that may limit movement. The child may not be able to walk or even put weight on the affected side.
Signs and Symptoms
Children with SCFE will exhibit certain characteristic symptoms that may even help the physician in assessing the type of SCFE. The signs and symptoms of stable SCFE include:
- Stiffness in the hip
- Pain in the groin, the thigh or the knee that lasts from several weeks to months
- Limping while walking
- Restricted movements of the hip
- Outward twisting of the leg
The signs and symptoms of unstable SCFE include:
- Severe pain similar to that felt during bone fracture.
- Inability to move the affected leg
Your doctor will diagnose the condition based on a careful medical history and physical examination where the walking pattern and hip movements will be monitored. X-rays of the hip confirm the diagnosis. Other imaging tests that may be ordered include:
- Bone Scanning: Bone scans help in the early detection of children at risk of avascular necrosis and chondrolysis, common complications of SCFE.
- Computed Tomography Scan: Computed Tomography (CT) scans reveal the degree of slippage.
- Ultrasonography: Ultrasound scan helps to distinguish between stable and unstable slip.
- Magnetic Resonance Imaging Scan: Magnetic resonance imaging (MRI) scan may suggest possible complications such as avascular necrosis.
The goal of treatment in SCFE is to prevent progression or worsening of the slippage and is accomplished through surgery. Surgery is usually performed within 24-48 hours of diagnosis.
The surgical procedures available for correcting stable Slipped Capital Femoral Epiphysis include
- Internal fixation (pinning) Bone-graft epiphysiodesis
- Corrective osteotomy
Internal fixation (pinning): This surgery is performed in a hospital setting under general anaesthesia. The patient may be positioned on their back during the procedure. The surgeon will make a small incision near the hip. With the use of fluoroscope (X-ray machine that captures continuous real-time images which are displayed on the TV monitor) as a guide, the surgeon will insert a metal screw or pin through the thighbone and the growth plate so that they are held in place. Your surgeon may use either a single central pin or multiple pins.
- Bone-graft epiphysiodesis: In bone graft epiphysiodesis the surgeon exposes the hip through iliofemoral approach. A rectangular shaped piece of bone is removed from the front part of the femoral neck. A tunnel is created through the growth plate and several corticocancellous strips taken from iliac crest bone are pushed into the tunnel across the femoral physis so that growth plate closure can be achieved.
- Corrective osteotomy: The surgeon exposes the hip by the anterior Smith-Petersen or anterolateral approach. A piece of bone is removed from the metaphysis of the femoral neck. This allows the epiphysis to be repositioned on the metaphysis without affecting epiphyseal blood supply. When the femoral neck gets shortened, the epiphysis is reduced and internally fixed with the help of 3 pins. Although, this procedure is anatomically sound, it is more invasive and may pose serious complications such as avascular necrosis and chondrolysis.
Surgical correction of unstable slipped capital femoral epiphysis can be done with internal fixation method where your surgeon makes a small incision near the hip and under the guidance of fluoroscope may advance the screw through the metaphysis, growth plate and epiphysis such that the screw holds all three structures in place.