Epiphysiolysis, also known as a growth plate fracture, is a condition affecting growing children and adolescents where the growth plate at the end of a bone separates or fractures, potentially disrupting normal bone development.
Understanding Epiphysiolysis
Epiphysiolysis refers to an injury involving the growth plate, which is a layer of developing cartilage tissue found near the ends of long bones in children and teenagers. These growth plates are responsible for bone growth and lengthening. When a child is still growing, these plates are weaker than the surrounding bone and more vulnerable to injury. The growth plate is the area where new bone forms, allowing bones to elongate as a child develops. Once growth is complete, these plates close and are replaced by solid bone.[13]
The structure of the growth plate consists of four regions that progress from cartilage to bone formation. The most common site of injury occurs in the hypertrophic region due to its structural weakness. This area is particularly susceptible because it has not yet fully developed into strong, mature bone tissue. The blood circulation to the growth plate is limited, and injuries can damage the small vessels that supply this crucial area, leading to various complications.[13]
One specific form of epiphysiolysis is Slipped Capital Femoral Epiphysis (SCFE), which occurs at the hip joint. In this condition, the ball at the head of the femur, or thighbone, slips off the neck of the bone at the growth plate in a backward direction. This causes pain, stiffness, and instability in the affected hip. The condition usually develops gradually over time, though it can sometimes occur suddenly after a minor fall or trauma.[3]
Epidemiology
Growth plate injuries are relatively common in the pediatric population. Studies show that epiphysiolysis accounts for approximately 15% to 30% of all fractures in children. The complication rate associated with these injuries ranges between 5% and 10%, highlighting the importance of proper diagnosis and treatment.[13]
When looking specifically at Slipped Capital Femoral Epiphysis, it is one of the most common hip disorders affecting pre-adolescents and adolescents. The condition occurs in approximately 10.8 per 100,000 children, though this rate can range from 0.33 to 24.8 per 100,000 depending on the population studied. SCFE most commonly develops during periods of rapid growth, shortly after the onset of puberty. The average age of onset is 11.2 years in females and 12.0 years in males, occurring between the ages of 10 and 14 years in girls and 12 to 16 years in boys.[3][4]
The condition affects males more frequently than females. Research indicates that SCFE is more prevalent in the northeast region of the United States than in the southwest. Racial disparities also exist, with higher rates observed among African-Americans, Hispanics, and Polynesians compared to other ethnic groups.[4][6]
Growth plate injuries most commonly occur in the wrist and ankle, though they can affect any long bone in the body. The left hip is more commonly affected in cases of SCFE, but approximately 25% of cases, with a range from 8% to 50%, are bilateral, meaning both hips are involved. In fact, in 20% to 40% of affected children, SCFE will be present in both hips at the time of diagnosis.[13][4][6]
Causes
Most cases of epiphysiolysis, particularly Slipped Capital Femoral Epiphysis, are considered idiopathic, meaning the exact cause is not well understood. Often, there is no history of significant trauma or injury before the onset of symptoms. The condition typically develops during periods when children are growing quickly and adult hormones begin to circulate in the body. During this time, the growth plate becomes weaker because it is broadening to accommodate rapid growth.[4][6]
The main cause of epiphysiolysis is usually related to sudden or repetitive stress on the growth plate during activities such as sports or accidents. Because throwing and other athletic movements involve the total body, lack of muscle strength or poor mechanics can lead to increased stress through the growth plate, raising the risk of injury. Young athletes who specialize in a single sport or who engage in repetitive overhead activities without proper rest are at increased risk.[14][17]
In some cases, epiphysiolysis has been associated with endocrine disorders, which are conditions affecting hormone-producing glands. These include hypothyroidism, hyperthyroidism, panhypopituitarism, and growth hormone deficiency. Hypothyroidism is the most common endocrine cause of non-idiopathic SCFE. Endocrine metabolic disorders may promote changes to the microstructure of the growth plate by increasing the thickness of the hypertrophic layer, enabling slippage even at early ages.[4][8][20]
Other associations have been reported between epiphysiolysis and renal disorders, Down syndrome, prior radiation therapy to the hip, and certain anatomical factors such as retroversion of the acetabulum or femoral head. These anatomical variations increase mechanical shear forces across the growth plate. Children who have undergone chemotherapy or taken certain medications, such as steroids, may also be at increased risk.[4][6]
Risk Factors
The single most significant risk factor for Slipped Capital Femoral Epiphysis is obesity. The excess weight places additional stress on the growth plate, increasing the likelihood that the femoral head will slip. Recent literature has shown an increased incidence of SCFE at younger ages, possibly reflecting the growing prevalence of childhood obesity.[4]
Male sex is another important risk factor, as boys are more likely to develop SCFE than girls. Periods of rapid growth also increase vulnerability, as the growth plate becomes temporarily weaker during these times of accelerated bone lengthening. Genetic predisposition plays a role as well, with the condition tending to run in families.[4][6]
Young athletes who specialize in a single sport year-round or who work with professional coaching without adequate rest periods face increased risk. Playing highly competitive sports and performing repeated overhead activities, such as in baseball pitching, tennis, volleyball, and swimming, can lead to overuse injuries of the growth plate. The repeated stress does not allow sufficient time for the body to heal any stressed tissue during rest periods.[6][17]
Children with hormonal abnormalities affecting the thyroid or other endocrine glands are at heightened risk. Those who have received radiation treatment or undergone chemotherapy may also have compromised growth plate integrity. Bone problems related to kidney disease can further increase susceptibility to growth plate injuries.[4][6]
Symptoms
The symptoms of epiphysiolysis vary depending on the location and severity of the injury. Common symptoms include pain, swelling, and difficulty bearing weight on the affected limb. Children may experience a sudden onset of pain during physical activity or after an injury. The affected limb may appear shorter than the other, and there could be limited range of motion. The presence of deformity, increased pain with touch, and difficulty moving the injured area are typical examination findings.[13][14]
In cases of Slipped Capital Femoral Epiphysis, pain in the hip or groin area is a common symptom that often worsens with activity. However, the pain may also be felt in the thigh or knee instead of, or in addition to, hip pain. This can sometimes delay diagnosis, as the actual problem is in the hip but the child complains of knee discomfort. Walking with a limp, trouble walking, or feeling like the leg is giving way are frequent complaints.[3][14]
Children with SCFE may walk with the affected leg turned outward, a finding called external rotation. When both hips are affected, which occurs in bilateral cases, the child may walk with a waddle. Some children find they are unable to sit with their knees straight ahead, as the knees tend to turn outward. Pain may subside with rest but is aggravated by activity.[3][14][6]
SCFE is often described based on whether the patient can bear weight on the affected hip. In stable SCFE, the patient is able to put weight on the affected hip, though it may be painful. The condition usually develops gradually over several weeks or months. Sometimes SCFE occurs suddenly after a minor fall or trauma, and the child may be unable to bear weight at all.[3]
Prevention
Preventing epiphysiolysis involves addressing modifiable risk factors and ensuring appropriate activity levels for growing children. Maintaining a healthy weight through balanced nutrition and regular physical activity is crucial, given that obesity is the single most significant risk factor for conditions like Slipped Capital Femoral Epiphysis.[4]
It is very important that young athletes get the appropriate amount of rest between periods of activity to reduce the amount of strain on the growth plate area. Normally, the body responds to pulling and stretching forces by healing any stressed tissue during times of rest. Young athletes who throw or pitch often without proper rest may develop overuse injuries. Avoiding year-round participation in a single sport and limiting work with professional coaching to ensure adequate recovery time can help prevent growth plate injuries.[17]
Proper training in sports mechanics and maintaining good muscle strength throughout the body can reduce stress on growth plates. Because throwing and other athletic movements are total body movements, ensuring adequate strength and proper technique is essential. Parents, coaches, and healthcare providers should be aware of the risks associated with repetitive overhead activities and encourage cross-training and rest periods.[17]
Early identification and management of endocrine disorders can also play a preventive role. Children presenting with symptoms suggestive of thyroid or other hormonal problems should be evaluated and treated appropriately. For children with risk factors such as previous radiation therapy, chemotherapy, or chronic kidney disease, regular monitoring and awareness of the signs of growth plate injury are important.[4]
Parents and caregivers should be vigilant for signs of limping, leg pain, or difficulty walking in children, particularly during periods of rapid growth. Seeking medical attention promptly when these symptoms occur can prevent complications and ensure proper treatment. Early recognition of a growth plate injury allows for timely intervention, which is crucial for the best outcomes.[14]
Pathophysiology
The pathophysiology of epiphysiolysis involves disruption of the normal growth and development process at the growth plate. The growth plate, or physis, is located between the widened part of the shaft of the bone, called the metaphysis, and the end of the bone, known as the epiphysis. In children, this area of developing cartilage is weaker than the surrounding mature bone, making it more susceptible to injury from mechanical forces.[3][13]
The growth plate consists of layers of cartilage cells at different stages of maturation. The earlier the injury occurs within these layers, the higher the risk of complications. The hypertrophic region, where cells are enlarged but not yet fully transformed into bone, is the most common site of injury due to its structural weakness. When stress or trauma occurs, the growth plate can separate, either completely or partially, from the bone.[13]
In Slipped Capital Femoral Epiphysis, the most likely mechanism for chronic slippage is rotation of the epiphysis on the metaphysis as a result of torque forces. Anatomical structural alterations that occur during adolescence are responsible for the greater incidence of the disease in this age group. During rapid growth, the growth plate broadens and becomes temporarily weaker, combined with hormonal changes that affect bone structure.[8][6]
The shapes of the femur and the socket, such as retroversion of the acetabulum or femoral head, can increase mechanical shear forces across the physis, leading to slippage. Endocrine metabolic disorders promote changes to the microstructure of the growth plate by increasing the thickness of the hypertrophic layer, enabling slippage even at ages when it would not typically occur.[4][8]
The blood circulation of the growth plate is poor, and injuries can damage the small vessels that feed the growth area. This vascular compromise can lead to complications such as avascular necrosis, where bone tissue dies due to lack of blood supply. Other potential complications include limb length inequalities, growth retardation, malunion, angular deformities, and bone bridge formation in the growth plate. A bone bridge, or physeal bar, can cause partial or complete growth arrest, leading to deformity or unequal limb lengths.[13]
Classification of epiphysiolysis is commonly done using the Salter-Harris system, which categorizes injuries based on the pattern of fracture through the growth plate and surrounding bone. Type I involves separation at the growth plate without involvement of the bone ends. Type II, the most common pattern, includes a metaphyseal fragment attached to the epiphysis. Type III involves the epiphysis and extends into the joint. Type IV crosses through the growth plate, metaphysis, and epiphysis. Type V is a compression injury to the growth plate. Complication rates generally increase in advanced stages as the injury approaches the germinal region where new bone cells form.[13][2]