Intra-articular fractures of the distal part of the radius treated with the small AO external fixator.

Thirty adults who had a severely comminuted intra-articular closed fracture of the distal part of the radius were treated by closed reduction and AO external fixation consisting of a converging-pin configuration with a double row of connecting bars. The patients were followed for an average of 2.6 years (range, two to four years). Twenty-seven patients had an excellent result; two, a good result; and one, a poor result, on the basis of pain, motion, strength, and radiographic appearance. Complications were rare, and there was no loss of fixation of the pins. The average grip strength was 92 per cent of normal. Motion of the wrist and rotation of the forearm averaged more than 90 per cent of that of the normal side. Carpal height was used as an indicator of distraction force produced by the fixator. There was an average increase in carpal height of four millimeters initially and 3.7 millimeters immediately before removal of the fixator, indicating near-constant distraction throughout the treatment. Radial length was well maintained, with shortening averaging less than one millimeter. The converging pins of the AO fixator prevent loosening, thereby diminishing the risks of infection, loss of reduction of the fracture, and breakage of the pins. This geometry of the pins allows the use of smaller-diameter (2.5-millimeter) pins and provides rigid fixation, even in osteoporotic bone.