Perthes disease is a condition characterized by inadequate supply of blood to the head of femur (thighbone) resulting in necrosis (softening and breaking down of the bone due to avascularisation) of the bone. It is also known as Legg-Calve Perthes disease or Legg-Perthes disease or avascuar necrosis.1 It is a childhood disorder, which affects the growth plate at the end of femur (clinically known as epiphysis) and the blood supply is compromised. This condition affects the hip and its movement.
A child with Perthes is usually well and this condition usually heals on its own over some time. The blood vessels that are devoid of blood supply grow over several months of time, and the blood supply to the dead bone returns and the bone begins to grow back. The cause of Perthes disease is not known and some studies suggest that it could be genetically passed down. It mostly affects children aged between 4 to 8 years old. It is more common in boys than girls (more likely to occur 5 times more in boys). It is very rare that the condition affects both the hips (in only 10 to 15% of the cases).
Is Perthes A Disability?
A disability is a condition which affects your day-to-day activities (restricts them) or interferes with a person’s ability to engage in daily tasks and actions either due to physical, mental, developmental or cognitive condition.2
The prognosis of this condition is good most of the times and it does not lead to any deformity in adults in maximum cases. However, very rarely when the bone does not grow back in time, it will lead to use of walking aids and that is when it becomes a disability.
The use of crutches and wheelchairs in case of a person affected with Perthes will fall under the category of being ‘disabled.’ It is only on cases where the condition is diagnosed very late and the disease has progressed to a state where the femoral head cannot be restored, and a destruction of more than 50% has occurred beyond which it cannot be restored.
Generally, Perthes disease is a temporary disability, which when diagnosed early in life, can be treated with a very good outcome. Early diagnosis and intervention can lead to normal ball and socket joint and normal healing with nil to minimal adverse effects on the joint.
Treatment Rationale
The rationale of the treatment is to limit the Perthes condition and its effects as far as possible and to avoid making the condition worse. This can be achieved by avoiding activities that can make the condition worse, which include high impact activities such as jumping or running. Pain medications can be given to reduce pain and rest can be advised. Crutches can also be used for some time to avoid any impact of walking that might deform the ball of the femur. For painful conditions, rest, wheelchair or crutches can be used with added observation and timely x-rays to analyze the progression of the condition.
If there is noted deformity with the head of femur changing its round shape and becoming more oval, then more aggressive treatment can be undertaken with physical therapy, exercise, bracing, traction and splinting of the joint. A splint, brace or plaster can also be used in cases where the range of movement of the hip in the child is affected.
When the joint can’t be contained with the above measures, then surgery is opted for to contain the head of the femur in the socket for proper movement of the joint and to limit any complications. In surgery, the joints (both femur head and acetabulum) are aligned together to minimize symptoms and complications.
Children having severe Perthes disease may have to undergo hip replacement surgery later in life. The affected individuals with Perthes disease may have a greater likelihood of developing arthritis in the affected joint later in life.
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