MSK - Perthes Disease

Question 1

Definition

Answer 1

Perthes disease involves disruption of blood flow to the femoral head, causing avascular necrosis of the bone. This affects the epiphysis of the femur, which is the bone distal to the growth plate (physis). The full name is Legg-Calvé-Perthes disease.

Question 2

Epidemiology

Answer 2

It occurs in children aged 4 – 12 years, mostly between 5 – 8 years, and is more common in boys.

Question 3

Aetiology

Answer 3

Idiopathic,
- One theory suggests that repeated mechanical stress to the epiphysis may interrupt the blood supply.

Question 4

Healing process

Answer 4

Over time there is revascularisation or neovascularisation and healing of the femoral head.

Question 5

Signs and symptoms

Answer 5

The severity of Perthes disease varies between patients.
Perthes disease present with a slow onset of:
- Pain in the hip or groin
- Limp
- Restricted hip movements
- There may be referred pain to the knee
There will be no history of trauma. If the pain is triggered by minor trauma, think about slipped upper femoral epiphysis, particularly in older children.

Question 6

Diagnosis

Answer 6

• FIRST LINE = X-ray = early changes include widening of joint space, later changes include decreased femoral head size/flattening however this can be normal.

Other investigations that can be helpful in establishing the diagnosis are:
- Blood tests are typically normal, particularly inflammatory markers that are used to exclude other causes
- Technetium bone scan
- MRI scan

Question 7

Conservative Treatment

Answer 7

Initial management in younger and less severe disease is conservative. The aim of management to maintain a healthy position and alignment in the joint and reduce the risk of damage or deformity to the femoral head. This is with:
- Bed rest
- Traction
- Crutches
- Analgesia

Question 8

Other treatment

Answer 8

• Physiotherapy = used to retain the range of movement in the muscles and joints without putting excess stress on the bone.
• Regular xrays = used to assess healing.
• Surgery may be used in severe cases, older children or those that are not healing. The aim is to improve the alignment and function of the femoral head and hip

Question 9

Complications

Answer 9

• Soft and deformed femoral head (MC), leading to early hip osteoarthritis. This leads to an artificial total hip replacement in around 5% of patients.

Question 10

Catterall criteria

Answer 10

Stage 1: Clinical and histological features only
Stage 2: Sclerosis with or without cystic changes and preservation of the articular surface
Stage 3: Loss of structural integrity of the femoral head
Stage 4: Loss of acetabular integrity