A positioning device to allow rotation for cine-MRI of the distal radioulnar joint.

'Cine-mode' magnetic resonance imaging (MRI) is useful in the diagnosis and treatment of patients with disorders of joint motion. We have designed a device for imaging of the distal radioulnar joint by cine-MRI. Five normal wrists and eight patients with rheumatoid arthritis were investigated prior to surgery for subluxation of the distal radioulnar joint. Normally, the radius moves in a constant arc around the ulna, whereas in rheumatoid wrists the centre of rotation varies continuously with increase in rotation. The device should prove helpful in imaging disorders of the distal radioulnar joint.