Perthes disease

Question 1

Define perthes disease

Answer 1

Avascular necrosis of the femoral head in children aged 4-8yrs
Due to disruption of blood flow and subsequent ischaemia.

Question 2

What is the key epidemiology of perthes disease?

Answer 2

Predominany in males 5:1
1 in 10,000 children annually
90% unilateral

Question 3

What is the relevant aetiology of perthes disease?

Answer 3

Genetic and environmental
Disruption in blood supply - clot, inc intr-osseus pressure, damage to the vessels

Question 4

What is the key pathological process of perthes disease?

Answer 4

Temporary disruption in blood supply to femoral head -> ischemia
Necrosis
Followed by fragmentation -> infarcted bone is reabsorbed, then undergoes reossification and remodelling

Question 5

What are the risk factors for Perthes disease?

Answer 5

Family history
Social deprivation
Factor V leiden and thrombophilia
Second-hand smoke exposure

Question 6

What are the cardinal symptoms of Perthes disease?

Answer 6

Gradual onset of limp
Hip pain, (may refer to the knee)
Note - more than 4 weeks suggests perthes disease and transient synovitis typically resolves within 2 weeks.

Question 7

What are the imaging signs of perthes disease?

Answer 7

Crescent sign - subchondral radiolucent zone -> sclerosis and fragmentation of the epiphysis.
X-rays

Question 8

What is the typical management of Perthes disease?

Answer 8

Mild or younger than 6yrs -> observation, physio, home exercises to encourage hip mobility. Avoid high impact until ossification complete

If more than 50% of the femoral head is involved -> plaster cast to keep hip abducted, osteotomy

Question 9

What are some potential complications of perthes disease?

Answer 9

Muscle wasting
Degenerative arthiritis later in life - deformation of the femoral head to be non-spherical.

Question 10

What is the typical prognosis of Perthes disease?

Answer 10

Good outcomes
May suffer from chronically from pain and osteoarthiritis.