“Coxitis Simplex” Transient Synovitis Hlynur Georgsson 24/11/2003

Etiology Remains obscure Remains obscure –Post-traumatic, allergic, infectious Inflammation of synovial lining Inflammation of synovial lining Often after URTI (32-50%) or virosis Often after URTI (32-50%) or virosis –4x increase in viral titers seen in 45% –Elevated interferon levels seen in 43% –No association shown with B-19 or HHSV6 History of Trauma in 17-30% History of Trauma in 17-30%

Epidemiology Most common cause of non-traumatic hip pain in children Most common cause of non-traumatic hip pain in children –Annual incidence 0.2% – % of pediatric ER admissions –lifetime risk 3% Typically children aged 3-8y Typically children aged 3-8y –Boys>girls 2:1 –Seasonal increase in Autumn? Bilateral 5% Bilateral 5% –Symptomatically unilat. show bilat. effusions in 25% Recurrence within 6 months in 4-15% Recurrence within 6 months in 4-15%

Presentation/History 6 year old non-febrile boy with a limp and uni- or bilateral hip-pain 6 year old non-febrile boy with a limp and uni- or bilateral hip-pain Onset Onset –Acute, typically less than one week at presentation Pain Pain –Partial flexion and external rotation to minimize intraarticular pressure –Internal rotation especially restricted during –Hip or groin region, occasionaly referred to ant. Thigh or medial knee Typically no fever or low-grade Typically no fever or low-grade

Workup Bloodstatus + WBC, ESR Bloodstatus + WBC, ESR X-ray X-ray –maybe unspecific soft-tissue changes Ultrasonography Ultrasonography –Can detect as little as 2-3ml of fluid Arthrocentesis Arthrocentesis –Ddx. Septic arthritis Three-phase bone scanning Three-phase bone scanning –Ddx. Osteomyelitis, osteoma, occult fracture

Treatment NSAID NSAID –Ibuprofen, Celebrex Aspiration therapeutic? Aspiration therapeutic? Full activity as tolerated vs. no weight-bearing? Full activity as tolerated vs. no weight-bearing? ? Traction ? ? Traction ? ? Antihistamine, i.m. Steroids ? ? Antihistamine, i.m. Steroids ? Full recovery 1-4w Full recovery 1-4w »1-2% may go on to develop Perthes disease with avascular necrosis of femoral head, Higher risk if delayed bone age Recurrence within 6m = 4-15% Recurrence within 6m = 4-15%