The value of traction during roentgenography of the wrist and metacarpophalangeal joints.

Traction on wrist and metacarpophalangeal joints during radiography produces 'vacuum phenomenon' due to the release of intra-articular gas. The resultant pneumoarthrogram clearly portrays the articular cartilage. Manual traction radiography of the wrist and the metacarpophalangeal joints has the following potential uses. 1. Detection of joint effusion; increased interosseous space during traction without release of intraarticular gas is indicative of joint disease with effusion. 2. Separation of the carpal bones; the traction separates the carpal bones and allows evaluation. 3. Differentiation of arthralgia from arthritis. 4. Evaluation of midcarpal, radiocarpal compartments, and the metacarpophalangeal joints can be performed before the secondary ossification centers are ossified. 5. Evaluation of the integrity of the joint cartilage.