Abrupt condylar destruction of the mandibula in juvenile idiopathic arthritis.

Unilateral and bilateral involvement of the temporomandibular joint (TMJ) and subsequent growth disturbance of the mandibula is a common feature in juvenile idiopathic arthritis (JIA). The prevalence varies between 17% and 87% depending on the subtype of JIA. No conclusive measures for local disease activity are found. Arthritis of the TMJ is usually not associated with pain, and clinical signals, such as deviation of the jaw, impaired opening of the mouth, absence of translation, crepitation, or clicking during palpation, are usually scarce, which explains the delay in diagnosis. The TMJ consists of fibrocartilage, hyaline cartilage, and synovial membrane like other joints. The growth centre of the mandible is located on the articular surface of the condylar caput instead of more distal to the joint, therefore the TMJ is more vulnerable to damage of the surface. Arthritis may cause rapid condylar destruction as the following case history illustrates.