What is it and how does it present?
Perthes’ disease, also known as Legg-Calvé-Perthes disease, affects the hip joint of children aged between 3 and 11 years old. The disease is uncommon affecting around 1 child in 9,000 and the exact cause is unknown. The condition can be generalised as the softening of the head of the femur bone (the ball part of the hip socket), which is eventually permanently damaged due to an inadequate blood supply to the bone cells. The damage caused can lead to arthritis of the hip later in life and it seems to affect boys more than girls with a ratio of 5:1 male to female.
When the condition worsens, the blood supply to the head of the thigh bone is disrupted, causing the bone beneath to die and the joint to deteriorate. This can cause pain, limping and limited movement of the hip joint. It is recommended that children with Perthes’ disease avoid high impact activities like running and jumping until the hip joint heals. Most children recover from Perthes’ disease, but it can take two or more years for the bone to regrow and return to normal. The collection of diagrams below explains the progression of the disease:
Symptoms of this condition tend to build gradually and can occur as any number of the following symptoms:
- An occasional limp in the earlier stages
- Stiffness and reduced range of movement in the hip joint
- Pain in the knee, thigh or groin when putting weight on the affected leg or moving the hip joint
- Thinner thigh muscles on the affected leg
- Shortening of the affected leg, leading to uneven leg length
- Worsening pain and limping as time goes by
For an accurate diagnosis, our physio team will usually take a thorough medical history, then complete a physical examination including hip range of movement, strength assessment, gait observation, and palpation of the joint. If we feel it could be Perthes disease or a number of other hip conditions which require further testing, we may refer to your GP or Consultant to complete an X-Ray, MRI, bone scan, ultrasound scan or blood tests. A referral for further investigation is not a cause for alarm, but simply our team being thorough to ensure the very best treatment approach for your child.
Stages of Perthes Disease
There are 4 stages during the process:
- Stage I: Avascular necrosis or initial stage (± 1 year) – At this stage of the disease, the blood supply to the femoral head is disrupted and bone cells start to die. The area becomes inflamed and irritated and signs of the disease, such as a limp or different way of walking, may develop. This first stage can last up to 3-4 months.
- Stage II: Fragmentation or resorptive stage (1 to 1 1/2 years) – Over a period of 1 to 2 years, the body removes the dead bone beneath the articular cartilage and quickly replaces it with an initial, softer bone (“woven bone”). It is during this phase that the bone is in a weaker state and the head of the femur is more likely to collapse into a flatter position.
- Stage III: Reossification stage (2-3 years) – The head of the femur starts to reshape and develop stronger bone. This stage is often the longest stage of the disease and can last a few years.
- Stage IV: Healed – Bone regrowth is now complete and the femoral head has reached its final shape. The spherical shape of the head will depend on several factors, including the extent of damage that took place during the fragmentation phase, as well as the child’s age at the onset of disease, which affects the potential for bone regrowth.
In around 60 percent of all cases, the blood supply to the hip joint returns and the femoral head regenerates by itself without treatment. This can take anywhere between two and five years. During this period, the bone is soft and vulnerable to damage.
Treatment of Perthes’ disease aims to make sure the femoral head remains as round as possible, and to reduce joint pain and stiffness. Treatment depends on the child’s age and the severity of their condition, but may include:
- Regular monitoring by your doctor, including physical examinations and X-Rays
- Pain medication
- Physiotherapy to help keep the hip joint moving and to help maintain muscle strength
- Avoidance of high impact activities such as running and jumping
- A brace, splint or plaster, may be used if the child’s range of movement in the hip is affected, or if X-rays show that the femoral head is losing its rounded shape
- Short term bed rest may be required when the pain is especially bad
- Rest using crutches, a walker, or a wheelchair for a period of time
- Surgery – some children require surgery to treat the deformed femoral head so that it fits snugly within the hip socket.
Generally, the younger the child is when they develop Perthes’ disease, the better the outcome. The degree of damage to the femoral head also determines the long-term outlook. Some children may develop osteoarthritis in the affected joint later in life, and in rare cases, hip replacement surgery may be required. However, most children respond well to treatment and are able to get back to their usual activities.
If you or your child are experiencing hip pain symptoms, please book an appointment to receive a thorough examination and recommendations with regards to moving forward!