Extensor tendon rupture after osteoarthrosis of the wrist associated with nonrheumatoid positive ulnar variance. Rupture of the extensor tendon after osteoarthrosis of the wrist associated with nonrheumatoid, positive ulnar variance is uncommon. Eight cases were seen in the last five years. They included five men and three women, whose ages ranged from 54 to 82 years (average, 70 years). In all the cases, roentgenograms revealed osteoarthrotic changes in the wrist and dorsal subluxation or dislocation of the ulnar heads. Seven cases had operations. Friction with the dorsally subluxated or dislocated ulnar head and the osteophytes surrounding it caused these tendons to rupture. It was impossible to use end-to-end sutures, so tendon transfers or tendon grafts were performed. The patients were evaluated one to four years after surgery. Three patients complained of some disability in their daily lives, notably, limited flexion of their fingers. It is important that during surgery the reconstructed tendons should not be strained excessively. 