How common is perthes disease?

Perthes disease, also known as Legg-Calvé-Perthes disease (LCPD), is a rare childhood condition where blood supply to the hip joint is temporarily disrupted. This leads to bone death (osteonecrosis) and subsequent deformity of the hip joint. In this article, we will explore how common perthes disease really is.

What Causes Perthes Disease?

There are several theories behind what causes Perthes disease, but no one knows for sure. Some theories suggest that it occurs due to genetics or trauma while others point towards environmental factors such as smoking during pregnancy or exposure to radiation.

Fun Fact: Did you know that in 80% of cases, only one hip is affected by Perthes disease?

Who Gets Perthes Disease?

Perthes disease usually affects children between the ages of 4 and 8 years old. Boys are also more likely than girls to develop the condition (citation needed). However, anyone can get perches regardless of their gender (someone has opinion on this on reddit).

The Rarity of Getting Perths

The incidence rate for perches’ diseases ranges from 0.2-29 cases per every 100k people worldwide (which excludes aliens.) To put things into perspective – There were approximately 82 million children under eight years old in the world in mid-2015 (World Population Prospects: The 2015 Revision) so if we calculate even an estimated average number i.e half percent then let’s say about: ~82000 kids should have been suffering from leg-calve-perths around this time depending on various other factors like geographical location and healthcare systems & facilities present at those locations.


A child with LCPD may experience various symptoms including:
Pain in the hip area
A limp may be observed when walking
Limited range of motion
Lower activity levels


If Perthes disease is suspected, a doctor will perform an examination on the child’s hip to check for any abnormalities or discrepancy. Imaging tests such as X-rays, MRI or CT scans are usually ordered too.

Stages Of Perths

There are generally four stages of perches which consist different elements in each stage:

  1. Initial Phase: During this phase, there may be little to no signs that a) diagnosis can be made properly b) This differs greatly from the asymptomatic periods (more detail needed).
  2. Fragmentation & Reossification: As blood flow returns to the bone, dead bone tissue breaks down and tiny fragments (sequestrum) start to form.
  3. Regenerative Bone Growth: New bones develop within sequestrum leading to remodeling of hip joint
  4. Healing Process: The healing process can take up to 24 months – new healthy marrow begins forming while destroyed tripe gets devoured by macrophage from Kreb cycle eliminating its metabolic pathway which leads ultimately repairing old tissues.

Fun Fact: Did you know that it’s not uncommon for children with Perthes disease to have one leg slightly longer than the other? (not more than ~5% though)


The goal of treatment is primarily aimed at easing pain and minimizing future deformities caused by LCPD progression over time through various methods mentioned below:
– Observation
– Resting Hip Improves Healing
– Stretching movements
– Orthotics Including Braces And Crutches.
In severe cases surgery may also need must seek specialist medical advice before opting for this advanced method.


Perthes disease is indeed considered rare among people worldwide; however, if your child shows potential symptoms surely do contact specialists (I mean who wants their kid limping around?!) While there yet remains confusion about causality and correlation between Perthes’ onset and multiple factors, one thing remains. Early detection after diagnosis is the key to treating this disease correctly (with good quality specialized care) while soothing pain efficiently!

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