Flexor Tendon Rupture of the Little Finger Caused by Calcium Pyrophosphate Dihydrate Crystal Deposition Disease of the Pisotriquetrum Joint

Abstract

We report a case of closed rupture of the flexor tendons of the little finger caused by calcium pyrophosphate dihydrate crystal deposition disease of the pisotriquetrum joint. The patient could not flex the little finger and did not have wrist pain. Plain radiographs of the affected wrist joint showed severe arthritic changes of the pisotriquetrum joint and calcification around the joint. At operation, the pisotriquetrum joint capsule was ruptured and involved the flexor tendon of the little finger. The distal stump of the flexor tendon was transferred to the flexor tendon of the ring finger, and the pisiform was resected. Histological examination with polarized light microscopy revealed crystals showing weakly positive birefringence in the calcification.

Closed rupture of extensor tendon resulting from untreated Kienböck disease

“…Attritional closed tendon rupture of finger is a well-known complication in rheumatoid arthritis, osteoarthritis, calcium pyrophosphate dihydrate crystal deposition disease, and distal radius fractures. [1,2,3,4,5,6,7] On the other hand, although closed tendon ruptures of fingers are a well-known complication due to in advanced Kienböck disease, only 23 cases (extensor 18, flexor 5 cases) have been reported in the English literature. [8,9,10,11,12,13,14,15,16,17,18,19,20] In previous reports, all the closed tendon ruptures were caused by the protrusion of fragments of the lunate bone or a mass of ectopic bone, suggesting the closed tendon ruptures are attritional ruptures in advanced Kienböck disease.…”