While the name is certainly daunting, slipped capital femoral epiphysis (SCFE) is not difficult to understand. However, in order to better explain the condition, it is necessary to understand the hip joint.
Basics of the Hip Joint
The hip is a ball-and-socket joint; range of motion is possible because of ball-and-socket joints. In the hip joint, the rounded end of the thighbone, or femur, fits into the hollow cup-shaped end of the pelvis bone.
In children who are still growing, there is a growth plate known as the epiphysis that separates the top of the thighbone from the rest of the bone; it is located just under the ball portion of the hip joint. The epiphysis’s main function is to connect the femoral head, the rounded “ball” part of the bone, to the femur while still allowing the bone to lengthen and grow. The epiphysis is made of cartilage, which is weaker than bone. During periods of growth spurts in children, the increase in body weight and height can put extra pressure on the joints. It is during these growth spurts, just before puberty, that SCFE is most likely to occur.
Slipped capital femoral epiphysis is a separation of the ball of the hip joint from the rest of the thighbone; it occurs at the epiphysis, the growth plate located at the upper end of the bone. Displacement may occur in one leg or it can affect both legs. With SCFE, an accurate and timely diagnosis with immediate treatment is critical in order to avoid complications. Patients may present with any of the following symptoms: difficulty in walking or walking with a limp, hip stiffness, pain while walking, knee or hip pain, an outward turning leg, or restricted and painful movements of the hip joint.
The causes for SCFE are not entirely clear. SCFE may result from a weakening in the growth plate, which can occur from trauma or inflammation or from changes in levels of hormones in the blood, which normally occur around puberty. At its worst, the separation can cause the top part of the thighbone to eventually lose its blood supply, decay, and collapse.
SCFE primarily affects children between the ages of 8 and 15 years old. SCFE occurs in nearly two of every 100,000 children. It commonly occurs in children during the periods of accelerated growth shortly after the onset of puberty. Typically, boys are affected more than girls. The condition seems to be more common in obese children. It can also develop in children with hormonal imbalances due to conditions such as thyroid dysfunctions, kidney disease, or growth hormone deficiency.
Other conditions that can increase the risk of developing SCFE include untreated infections of the hip joint, bone disorders, exposure of the pelvis to radiation or chemotherapy, or a patient taking certain medications such as steroids. A family history of SCFE is another risk factor for the condition.
Stable SCFE, also known as “mild slip SCFE”, is the common type of SCFE in which the child affected with SCFE can walk with or without crutches. Stiffness of the hip is usually the first symptom to develop in a child with stable SCFE. Initially, the stiffness improves and the joint becomes more flexible by resting the joint. If resting does not improve the condition, the stiffness may increase and cause a limp. The child may also experience pain that comes and goes in the groin, thigh, hip or knee. As the condition progresses, the child loses some ability to move the affected hip. The involved leg twists out and starts to look shorter than the other leg. The child may find it difficult to participate in life to varying degrees, from performing simple tasks like bending over to tie his or her shoes to being active in more demanding activities like playing sports.
A more severe slip – unstable SCFE – is very painful and the child might not be able to put any weight on the affected side. It usually develops in a child after a trauma or a fall. Because the joint cannot move as much, the affected foot and leg may begin to quickly turn outward. An unstable SCFE is also serious because it may restrict blood flow to the hip joint. A stable SCFE can turn into an unstable SCFE, especially if the child sustains a fall on the affected leg.
A doctor diagnoses SCFE based on a detailed history, physical examination, and by performing X-rays of the hip joint. During the physical examination, the doctor will observe the gait or walking pattern and restricted hip motion of the patient while gauging pain reported by the patient when the patient is attempting various hip movements. An X-ray of the affected hip joint is sometimes sufficient to see evidence of displacement or separation of the head of the thighbone from the rest of the bone. If X-ray studies are normal, the doctor may ask for a magnetic resonance imaging (MRI). An MRI is performed because the MRI is more sensitive than an x-ray, and it can dramatically highlight contrasts in soft tissue, making it especially useful for an examination of joints and cartilage. The doctor will also look for clinical signs of hormonal disorders and may order blood tests to assess the status of the thyroid and pituitary glands, as well as the kidneys.
At this time, surgery is the best solution to stabilize the slipped bone in cases of SCFE: either in situ pinning surgery or open reduction surgery.
In situ pinning surgery is a less invasive surgery where one or two screws are placed through the skin into the thighbone to hold the epiphysis to the top of the thighbone and prevent further slipping.
In open reduction surgery a surgeon cuts into the leg and physically realigns the bone within the hip socket and prevents loss of blood flow to the ball of the thighbone. Open reduction surgery is usually performed on patients with unstable SCFE. The doctor may also suggest using pins on the unaffected hip to stabilize it even if it has not slipped as the risk is high in some children and it prevents waiting until a slip occurs in the unaffected hip.
Before surgery, the doctor will recommend lots of rest and the use of crutches to avoid putting weight on the affected leg in order to prevent any further slippage. After surgery, the hip is immobilized in a cast for a time period ranging from several weeks to two months, depending on an individual’s recovery time.
With in situ surgery, the child may need to use crutches to walk for anywhere from four to six weeks after surgery before putting limited weight on the hip. After open reduction surgery, the child is kept on crutches for 12 weeks and not allowed to bear any weight on the hip. If both hips have been treated, the child needs to use a wheelchair for the first couple of weeks after surgery. After the initial keep-weight-off period (usually three months, but will vary per person), the child can slowly get back to normal activities, and even begin to integrate running and contact sports. Incorporating physical therapy into any recovery plan is essential after surgery to strengthen the hip and leg muscles.
In stable SCFE, there are good chances of complete recovery. Unfortunately, children who have unstable SCFE are at an increased risk of developing complications. Any delay in diagnosing the condition can lead to complications.
Avascular necrosis develops due to lack of blood supply to the bone and may result in the collapse of the femoral head.
Chondrolysis is a disintegration of the cartilage surface and occurs due to the decay of the cartilage in the bone.
In rare cases, the hip joint may wear away despite prompt diagnosis and treatment.
The best defense against any complication is early detection, diagnosis, and prompt decisions on a treatment plan.
No one can prevent SCFE, but if slipped capital femoral epiphysis is caught early, there is a very good chance for a full recovery. One thing that can be done to lessen the risk of SCFE is to maintain a body weight within the normal range per the person’s build and age. Maintaining a healthy weight can go a long way in sparing the bones and joints from excess wear and tear that can weaken and damage them.