ESR
Management
Incidence
Knee > Hip
- superficial position
- limited cover of well vascularised muscle
- watershed area of skin blood supply anterior to the skin incision
- much increased in fully constrained prosthesis
Ideal < 1%
Risk Factors
Increased with
- revision
- prior infection
- RA / Psoriatic arthropathy
- DM
Painful THA
Aetiology
Intrinsic
Infection
Loosening
Thigh pain in uncemented
- micro motion at distal end of stem
- modulus mismatch
Stress fracture / insufficiency fracture
- pubic rami, sacral
Intra-operative fracture
Prosthesis failure
Subtle instability
Extrinsic
Transient synovitis / Septic arthritis
Definition
Transient synovitis of unknown aetiology with complete resolution
Epidemiology
Most common cause of hip pain
- 1 /1000
May occur in 3% of children with majority not seeking medical attention
Wide range of age
- from 9 / 12 to teenagers
- usually 3 - 8 years
- peak 6 years / same as Perthes
More common in
- boys 2:1
- caucasian