Introduction
This is a condition that is characterized by loss of blood supply to the capital femoral epiphysis.
Anatomy
Describe the pertinent anatomy and provide links to relevant pages
Pathogeneis
Describe the biologic basis of the disorder or the mechanism of injury
Natural History
The disease goes through various stages, which include, stage of synovitis, stage of fragmentation, stage of reossification and remodelling.
Patient History and Physical Findings
AGE: THe usual age at onset is 4-8 years
GENDER: Boys are more commonly affected than girls.
BILATERALITY: Bilateral involvement may be seen in approximately 20% of cases. Radiographic evidence of bilateral "Perthes" like changes should raise the suspicion for Multiple, epiphyseal dysplasia, Gaucher's Disease, Sickle cell disease and Hypothyroidism.
SYMPTOMS:
The usual presentation is hip pain and or limping.
EXAMINATION:
There is restriction of hip motion- most often internal rotation and abduction on the affected side. There may be a hip flexion contracture as demonstrated by the Thomas' test. Affected children will usually walk with an antalgic gait.
Imaging and Diagnostic Studies
Radiographs may be negative in the early stages. MR imaging demonstrates avascular changes well before changes are seen on plain films. Bone scan has extensively been used in the diagnosis and prognostication of Perthes disease.
Plain films should include antero-posterior and frog-leg lateral views. The earliest sign on plain films is the Waldenstrom sign with increase in the medial clear space. With further involvement there may be a crescent sign noted (more obvious on the frog leg lateral) which is indicative of a subchondral fracture. The Salter-Thompson classification is based on the extent of the crescent sign (Salter Thompson A: less than 50% involvement and Salter-Thompson B : crescent extends more than 50% across the head).
Stage of Fragmentation: In this stage there is progressive sclerosis and flattening of the capital femoral epiphysis.

Figure: Perthes coxa-breva
Differential Diagnosis
Transient synovitis (Toxic synovitis)
Infection: Tuberculosis, Lyme disease
Sickle Cell disease
Multiple epiphyseal dysplasia
Treatment
Include:
Medical therapy
Nonoperative treatment
Operative treatment - include links to pages with detailed surgical techniques
Indications and contraindications
Pearls and Pitfalls
Tips and problems to avoid
Postoperative Care
Include immediate postoperative care and rehabilitation
Outcome
- Residual proximal femoral deformities, including:
- Coxa breva
- Coxa magna
- Coxa plana
- Many go on to develop degenerative hip disease
Complications
Include overview of complications
Selected References
Insert selected references and landmark articles