Rupture of the extensor digitorum communis tendons caused by occupational overuse.

Spontaneous rupture of the extensor pollicis longus tendon in excessive exertion is well-recognised, but similar rupture is rare in the common extensor tendons of the fingers. Two cases caused by occupational overuse are reported. Mechanical attrition at the distal edge of the extensor retinaculum produced by excessive use was thought to be responsible for the rupture.