Slipped capital femoral epiphysis

# Overview
Slipped capital femoral epiphysis (SCFE) is a medical term referring to a fracture through the epiphyseal growth plate.
The capital (head of the femur) should sit squarely on the femoral neck. Abnormal movement along the growth plate results in the slip. The femoral head is displaced posteriorly and inferiorly in relation to neck of femur. Despite its rarity, it needs to be addressed immediately for the fear of avascular necrosis.
Often this condition will present in obese prepubescent males, especially young black males, and sometimes females with an insidious onset of thigh or knee pain with a painful limp. Hip motion will be limited, particularly internal rotation.
The Centers for Disease Control offers a body mass index (BMI) calculator to help you determine your risk for obesity. 
The disorder can sometimes be associated with endocrinopathies such as thyroid problems.

# Classification
- Stable- patient can ambulate.
- Unstable- patient cannot ambulate even with crutches. There is high chance of AVN
- Acute
- Chronic
- Mecasermin

# Differentiating Slipped capital femoral epiphysis from other Diseases
The following conditions must be looked out for in a young patient with hip pain-
- Avascular necrosis of femoral head
- Fracture of neck of femur
- Stress fracture of neck of femur
- Injury to the groin
- Osteitis pubis
- Apophyseal avulsion fracture
- Hip apophysitis
- Transient synovitis
- Legg-Calve-Perthes disease
- Septic arthritis

# Complications
- Deformed joint
- Avascular necrosis
- Chondrolysis or destruction of articular cartilage
- Osteoarthritis
- Bone length abnormalities

# Diagnosis

## History and Symptoms
SCFE most commonly affects the left hip compared to the right. The patient presents with a knee pain and painful limp. The duration of symptoms for more than 3 weeks is considered to be chronic. It is also associated with some endocrine disorders like hypothyroidism, panhypopituitarism, renal osteodystrophy and growth hormone abnormalities.

## Physical Examination
In any case of knee pain, the clinician should not forget that the pain may be referred from the hip. The gait may be antalgic. The sign to note in this condition is affected hip held externally rotated. To differentiate between stable versus unstable types, determine ability to bear weight on the affected side.
In hip examination, the two sides must always be compared. With patient lying down and knee flexed at 90 degrees, test for rotation at hip joint. On passive hip flexion now, the leg would rotate externally and abduct, if SCFE is present.

## Laboratory Findings
Even though SCFE is associated with a number of endocrine disorders, it is not a routine practice to do laboratory testing for all such disorders after a diagnosis of SCFE. The diagnostic tests specific to the endocrine disorders must be performed only when these disorders are actually present.

## X Ray
This disease warrants x-rays of the pelvis (AP and frog lateral).  The appearance of the head of the femur in relation to the shaft likens that of a "melting ice cream cone".
- In A-P view, a radiographic calculation called a Klein line can be used to diagnose SCFE. This line is drawn from the superior portion of the femoral neck and it should pass through a potion of the head. If it does not , then SCFE is probable. The severity of the disease can be measured using the Southwick angle.
- In Frog leg view, a line drawn through the center of neck should meet the center of the epiphysis proximally. If it meets anterior to it, then it is likely SCFE.
Any bony changes in the femoral neck and head must be looked for in view of chronicity of SCFE.
On imaging, Salter-Harris type 1 fracture of the proximal femoral epiphysis with posterior-medial displacement of the proximal femoral epiphysis is seen.
Bone scans and MRI are not routinely done.
Patient #1: Radiographs demonstrate left slipped capital femoral epiphysis
Patient #2: Radiographs demonstrate right slipped capital femoral epiphysis

# Treatment
The main risk of a SCFE is avascular necrosis. With that in mind, its management is considered an emergency. There is no role for observation. When diagnosis is clear and SCFE has been classified as acute or chronic, stable or unstable, immediate treatment is required.
Since this condition is associated with a variety of endocrinopathies, there is a tendency for bilaterla involvement. The patient must be explained of this and prophylactic treatment, though controversial, may be required on the asymptomatic, unaffected hip as it is bound to have the same fate in future. Review on individual basis should be done. A patient with multiple endocrine disorders may need prophlactic treatment on the other hip joint.
Delay in diagnosis or treatment could complicate the condition and make a stable SCFE , an unstable one.

## Surgery
The treatment of choice is internal fixation using a cortical screw preferably within 24 hrs of onset. This prevents further slippage and helps closure of epiphysis. Others such as Dr. Ganz advocate open reduction and pinning. The risk of reducing this fracture is disruption of the blood supply.
Osteotomy of proximal femur is 2nd line treatment reserved when the femoral head needs to be repositioned with advancing age.
Consultation with the endocrinologist is required for young patients and also when clinical examination suggests an underlying endocrinopathy.