WRIST ANATOMY - INCIDENCE, DISTRIBUTION, AND CORRELATION OF ANATOMIC VARIATIONS, TEARS, AND ARTHROSIS

We dissected 393 wrists to evaluate the incidence and distribution of anatomic features, arthrosis, chondromalacia, and soft tissue lesions. The data were then analyzed for any statistically significant associa tions among the different variables. The most common (73%) lunate morp hology had a separate medial facet on its distal surface for the hamat e. The capitate had a separate facet for the fourth metacarpal in 86% of the wrists. Fourth metacarpals with a dorsal radial facet, either s eparate from or connected to the rest of the fourth metacarpal base, w ere the most common types of fourth metacarpal. Cartilage erosion with exposed subchondral bone was identified in 58% of the wrists. It was most commonly at the proximal pole of the hamate (28%). Tears of the l igaments and/or the triangular fibrocartilage complex were identified in 56% of the wrists. The triangular fibrocartilage complex was found torn in 36% of the wrists. The lunotriquetral interosseous ligament wa s torn in 36% of the wrists, and the scapholunate interosseous ligamen t was torn in 28% of the wrists. There was a communication between the proximal wrist joint and the pisotriquetral joint in 88% of the 76 wr ists, which were further dissected to assess this issue. Statistical a nalysis of the data found a significant correlation between the presen ce of cartilage erosion at the proximal pole of the hamate and the pre sence of a lunate facet. There was also a significant correlation betw een the presence of a tear in the scapholunate interosseous ligament a nd the presence of cartilage erosion in the scaphoid-trapezium-trapezo id joint. Analysis of the paired wrists from 169 cadavers revealed tha t the same soft tissue tear or combination of tears was present bilate rally in 39% of the pairs. Cartilage erosion was present bilaterally i n the same location or locations in 27% of the pairs.