This study assessed the risk factors for spontaneous extensor tendon rupture in the rheumatoid wrist. The rupture group consisted of 25 wrists that had rupture of the extensor tendons and later received tendon reconstruction. The non-rupture group included 77 rheumatoid wrists without extensor tendon rupture. We assessed patients' pain at the distal radioulnar joint and swelling in the extensor tendon compartments clinically, matrix metalloproteinase-3 level in blood samples, and radiographic findings. We found that swelling in the extensor tendon compartments, the scallop sign, and severe dorsal subluxation are significantly associated with spontaneous extensor tendon rupture, but serum matrix metalloproteinase-3 level is not.Level of evidence: IV.
Keywords: Extensor tendon; rheumatoid arthritis; risk factor; tendon rupture.