Introduction:
The longest bone of the thigh is called the femur. The end part of any long bone is called the epiphysis. The upper part of the femur contains the head and neck, the middle long part is called the shaft, and the thickest lower part has two condyles. The head of the femur is globular shaped, and it articulates with a concave cavity in the hip bone called the acetabulum (hip socket). This is known as the hip joint. The hip joint is a ball, and socket type of joint, and its primary function is to support the weight of the body. The slipped capital femoral epiphysis is a common hip joint disorder in adolescents.
What Is Slipped Capital Femoral Epiphysis?
The slipped capital femoral epiphysis is a medical term that refers to the slippage of the epiphysis of the upper part of the femur from the hip socket. It is the neck along with the shaft that gets displaced from the hip socket in the front and upward direction. This condition is more common in adolescence during the rapid growth phase. Males have a higher risk of incidence than females. Slippage is frequent on the left side, although bilateral slippage is also common.
What Are The Types of Slipped Capital Femoral Epiphysis?
Slipped capital femoral epiphysis may be classified as follows:
Based on Symptoms:
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Acute: There is a sudden displacement of the bone with severe pain.
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Chronic: The onset and symptoms occur gradually.
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Acute on Chronic: The condition may be persisting for more than a month with a recent exacerbation of pain.
Based on Functionality:
A novel classification system was formulated in 1993 based on the weight-bearing ability of bone. It is otherwise known as Loder’s classification.
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Stable: The bone can bear weight, and the patient can walk without crutches. The slippage is less severe with a good recovery rate. There is less chance for avascular necrosis (bone death).
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Unstable: The bone is not able to bear weight, and the patient is unable to walk even with crutches. The slippage is more severe with a bad recovery rate. There is more chance of avascular necrosis (bone death due to lack of blood supply).
Based on the Head Shaft Angle:
The angle formed between the head and the shaft of the femur measured on a radiograph is called the Southwick angle. The severity of the disease can be calculated using the Southwick angle.
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Mild: It is a grade I condition where the angle is below 30 degrees.
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Moderate: It is a grade II condition where the angle is between 30 and 60 degrees.
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Severe: It is a grade III condition where the angle is above 60 degrees.
What Are the Causes of Slipped Capital Femoral Epiphysis?
The growth plate or the growth center of the femur is located between the epiphysis and the shaft of the femur. This growth center eventually becomes the femur head. During adolescence, the growth plate is the weaker area of the bone since it is not fully developed. Hence it is the area that breaks frequently and causes the head of the femur to stay in the socket while the rest of the femur shifts. Some of the factors that lead to the weakening of the growth plate are:
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Injury: Any local trauma that fractures the growth plate of the femur.
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Obesity: Overweight is a major risk factor and puts excess pressure over the growth plate.
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Endocrine Disorders: Thyroid and growth hormone problems are associated with slipped capital femoral epiphysis since it impairs normal bone formation.
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Kidney Failure: Kidney problems hinder normal bone growth.
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Hereditary: Slipped capital femoral epiphysis runs in families, especially in boys.
What Are the Symptoms of Slipped Capital Femoral Epiphysis?
The symptoms of slipped capital femoral epiphysis depend on the severity of the condition. The onset of symptoms is gradual and slowly progressive. Common symptoms are:
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Limping due to pain in action.
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The affected leg appears shorter than the other.
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The leg rotates in an outward direction while walking.
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Loss of flexibility in the hip joint.
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The pain may radiate along the thigh and knee.
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In severe cases, there is a spasm of the hip muscle.
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As the disease progresses, the bones become more brittle.
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There may be a reactive bone formation at the femur neck.
How to Diagnose Slipped Capital Femoral Epiphysis?
Diagnosis is based on the patient's symptoms and radiological findings.
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Physical Examination: The medical history and general health of the patient is evaluated. Physicians may perform careful examination and manipulation of the affected hip and leg to check for pain, range of motion, and walking difficulty.
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Imaging Techniques:
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X-rays of the pelvis will show the displaced head of the femur in relation to the shaft.
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CT (computed tomography) scan is used to visualize early slipping and provides an accurate measurement of the extent of displacement and angulation.
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MRI (magnetic resonance imaging) is needed if X-rays are inconclusive of the diagnosis.
How to Treat Slipped Capital Femoral Epiphysis?
The treatment of slipped capital femoral epiphysis aims to prevent further slip, reduce the displacement and avoid complications. Conservative management involves rest, over-the-counter painkillers, non-weight-bearing activities, physical therapy, and traction. In most cases, surgery is the choice of treatment.
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In Situ Fixation: Currently, in situ fixation is most often used for mild or moderate acute cases. A small incision is made, and a pin is placed across the growth plate to keep the head and shaft of the femur in position.
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Open Reduction: This procedure may be indicated for more severe cases with chronic slipping. Once the incision is made, a gentle manipulation is performed manually to reduce the head to a normal position, and then the screws are fixed.
The chances of slippage are common in the other hip joint, and therefore the affected hip may also require pinning or screwing at the same to reduce the risk of slipped capital femoral epiphysis.
Chronic slippage with severe displacement produces permanent irregularities in the femur head and the hip socket. In such a situation, the osteotomy is preferred to restore the normal relationship between the femur head and neck. It further prevents degenerative joint disease.
Conclusion:
Slipped capital femoral epiphysis must be diagnosed as quickly as possible and treated early. Without proper treatment, slipped capital femoral epiphysis can lead to several complications like degeneration of the femur head and arthritis of the hip. Parents must be kept aware of the condition and educated to consult a pediatric orthopedician for optimal treatment planning and to reduce complications.
