M67: Other disorders of synovium and tendon

M67.3: Transient synovitis

Transient synovitis, also known as toxic synovitis, is a condition that commonly affects children and is characterized by an inflammation of the hip joint. Usually, it affects only one hip, but in rare instances, both hips may be involved. The exact cause of transient synovitis is unknown, but it may be linked to viral infections and allergies. The main symptom is hip pain which is often accompanied by a limp or difficulty walking. Pain may also be felt in the thigh, knee, or groin area. Symptoms typically appear suddenly and may peak after 1 to 3 days. The good news is that transient synovitis is temporary and usually resolves on its own within one to two weeks, leaving no lasting effects.