Synopsis
Recognise childhood femoral-head osteonecrosis, preserve hip motion and containment during biological fragmentation and select reconstruction by age, head involvement and mechanical congruence.
- Perthes disease is idiopathic osteonecrosis of the capital femoral epiphysis, classically presenting between four and eight years with limp and hip, thigh or knee pain.
- High-yield examination shows reduced hip abduction and internal rotation, an antalgic or Trendelenburg gait and possible thigh wasting.
- First-line imaging is bilateral AP pelvis and frog-leg lateral radiography; obtain MRI when early disease remains suspected despite normal films.
Key red flags
Fever, severe rest pain, systemic illness or marked inflammatory response is not typical Perthes disease and requires emergency infection assessment.
Investigation priorities
Identify epiphyseal density, collapse, extrusion, acetabular coverage and bilateral or alternative disease.
Management branches
A young child has ongoing limp, referred knee pain or loss of abduction and internal rotation.
- Assess fever, systemic state, weight-bearing ability and red flags before performing gentle bilateral hip examination.
- Obtain AP pelvis and safe frog-leg lateral views of both hips and review previous transient-synovitis episodes.
Key medicines
Ibuprofen for painful inflammatory phasesUse the current BNFC age- and weight-specific oral dose for a short course with food when the child is hydrated and has no renal, gastrointestinal or NSAID-sensitive asthma contraindication.
Paracetamol as alternative or adjunctPrescribe the BNFC dose for the child's age and weight with the exact formulation volume, interval and 24-hour maximum recorded for carers.