Distal radioulnar joint incongruity after shortening of the ulna.

Coronal sections of the distal radioulnar joint (DRUJ) were studied in 13 preserved cadaveric wrists specimens before and after 2 mm of shortening of the ulna. The DRUJs were subclassified on the basis of the DRUJ angle and depth of the sigmoid notch. The changes in extent and location of area of contact and radioulnar separation were noted. Although reduction in area of contact occurred in every specimen and DRUJ type, the maximum radioulnar separation and reduction in area of contact occurred in the DRUJ type IB and IIB. This could be a possible factor producing point loading and subsequent occurrence of DRUJ remodelling in the long-term after shortening of the ulna.