Late secondary rupture of flexor pollicis longus masquerading as primary trauma.

Two cases of loss of function of the flexor pollicis longus tendon are presented. Initial assumptions that these were cases of primary tendon rupture proved to be wrong when unexpected intraoperative findings suggestive of previous long standing tendon rupture were later matched with a history of previous trauma. Spontaneous subcutaneous rupture is rare in otherwise healthy tendons.