Ulnar subluxation of a ruptured EPL tendon at the metacarpophalangeal joint: case report.

We report a case of ulnar subluxation of a ruptured extensor pollicis longus tendon at the metacarpophalangeal joint due to tethering of the distal tendon and an abnormal vector of pull. In this case, thumb flexion with the tethered EPL tendon resulted in attenuation of the radial sagittal band of the extensor hood. After plication of the radial sagittal band and relocation of the EPL tendon, adequate thumb extension was restored.