Anatomic study of the pisotriquetral joint: ligament anatomy and cartilagenous change.

Eighty embalmed cadaver wrists (40 right and 40 left, 55 male and 25 female, aged 36 to 93 years [average age, 72.5 years]) were dissected to assess the anatomy of the pisotriquetral joint and the location of degenerative changes. The patterns of degenerative changes were classified into five types: type 1, central (8.8%); type 2, peripheral (38.8%); type 3, fan-shaped (13.8%); type 4, mixed (combination of > or =1 of types 1, 2, and/or 3; 10.0%); and type 5, total (12.5%). There was no cartilagenous change in 16.2% of the pisoform and 13.7% of the triquetrum. Degenerative changes (exposed subchondral bone and chondromalacia) on the articular surface of the pisiform were present in 83.3% of the wrists and on the triquetrum in 86.3% of the wrists. Degenerative changes were most commonly of the type 2 pattern (peripheral), with change located most commonly in the distal, distal-radial, and radial aspects of the pisiform and triquetrum. The ligamentous anatomy was categorized into 3 different types: type A, pisohamate and pisometacarpal ligaments inserted on the palmar distal aspect of the pisiform (52.5%); type B, pisohamate ligament inserted on the radial side of the pisiform and pisometacarpal ligament inserted on the palmar side of the pisiform (41.3%); and type C, type B anatomy with an additional ligamentous slip between the pisometacarpal ligament and the distal aspect of the hook of the hamate (6.2%).