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Slipped capitol femoral epiphysis is a common hip disorder in adolescents, in which the growth plate fractures. The result is a slippage between the neck of the femur and the overlying head of the femur, also called the capital, or epiphysis. Normally, a growing femur has four main parts.
There's the diaphysis, which is the long and hard part, also called the shaft of the bone. And that extends to the metaphysis, at the level of the femoral neck. Above the femoral neck lies the cartilaginous growth plate, also called the physis. The cartilaginous growth plate has cells which divide and enable the bone to grow in length. These cells are very active in adolescence, and they enable a growth spurt.
During this period, the growth plate is relatively weak and vulnerable to shearing forces. Eventually, the cartilaginous growth plate ossifies and fuses with the epiphysis. This happens around the age of 16 in females and 19 in males.
Now, before the growth plate ossifies, it's supported by the perichondrial ring. which is a dense connective tissue that extends from the metathesis to the epiphysis. The perichondrial ring helps resist shearing forces so that the femoral head and the femoral neck don't slip away from each other. You see, the ball-shaped head of the femur comes and sits within the cup-shaped socket called the acetabulum.
This makes a ball-and-socket type of joint, which is kept stable by a tough fibrous joint capsule and a rope-like ligament known as the ligamentum teres. The ligamentum teres arises from the base of the acetabulum, known as the acetabular fossa, and that attaches to the fovea capitis, the depression found on the tip of the femoral head. Around the femoral neck, there are epiphyseal blood vessels that supply the cells of the femoral head with nourishment.
In slipped capitol femoral epiphysis, the perichondrial ring becomes too weak to resist the shearing forces between the femoral head and the femoral neck, causing the two to gradually slip away from each other. Actually, it's not the epiphysis that slips away as the name of the disease suggests, because the epiphysis is well held in the acetabulum by the joint capsule and the ligamentum teres femoris. In reality, it's the neck that displaces anterolaterally and superiorly.
That makes it look like the epiphysis has slipped down and backwards. If the displacement is severe, it can tear the epiphyseal blood vessels, interrupting the blood supply to the femoral head. If that happens, the epiphyseal cells can starve and start dying off, a process called a vascular osteonecrosis of the femoral head. Now, the exact cause of slipped capitol femoral epiphysis is not understood, but there are some well-known risk factors like obesity.
It's thought that the extra weight might increase the pressure on the epiphysis-physis junction, which can result in a slippage. Other risk factors include hyperthyroidism and a family history of the disease. When slipped capital femoral epiphysis is mild, it can cause intermittent pain in the groin, which can sometimes feel like it's coming from the thigh or the knee.
This pain can worsen with activities like walking or running, and it can cause a limp. In severe cases, individuals may become unable to walk, and the affected leg may appear 1-2 cm shorter and externally rotate compared to the unaffected leg. Over time, it can also become difficult to do internal rotation and abduction with the affected leg. The diagnosis of the slipped capito-femoral epiphysis requires pelvic x-rays. The x-ray is taken in a frog-leg lateral view, which is where the hip is flexed and extended to help visualize the joint.
The slipped capitofemoral epiphysis is diagnosed when the joint space is widened, and the femoral head looks displaced, most often posteroinferiorally. The treatment of slipped capitofemoral epiphysis is usually a surgery to stabilize the femoral head to prevent further slipping. This is done by surgically fixing screws and pins through the growth plate to the femoral head.
It requires a period of rest with limited weight bearing until the hip heals and becomes stable. In some cases, there's prophylactic fixing of the contralateral hip, even though it may look normal. Alright, as a quick recap. In slipped capital femoral epiphysis, there's a slippage between the neck of the femur and the overlying head of the femur, and it mainly affects adolescents.
People with slipped femoral epiphysis present with limping and intermittent pain in the groin, which may be referred to the thigh or the knee, and in severe cases, they may become unable to walk. Also, the affected leg usually appears shorter and externally rotated compared to the normal one. The diagnosis involves taking a frog leg lateral view of the pelvis, and treatment consists of surgically stabilizing the slippage with screws that stabilize the femoral head.