How to Diagnose Synovitis
Your doctor will do a physical exam to discover which movements cause or worsens pain. This may involve moving your child’s knees, hips, and other joints. Your doctor may also recommend an ultrasound of your joint to check for fluid in the joint, which is a primary sign of inflammation.
Your doctor may also recommend blood tests to see how severe the swelling is. Your doctor may check for other causes of joint pain, such as Lyme disease. In some cases, your doctor may have to remove a fluid sample and send it to a lab for testing. This is usually done when the swelling or fever is severe and your doctor has not ruled out septic arthritis.
Your doctor may also recommend X-rays to rule out Legg-Calve-Perthes disease [2] or SCFE.