Chondral lesions of the midcarpal joint.

Wrist arthroscopy performed on 78 patients showed 35 lunates of Type I (44.9%) i.e., having only one facet on their distal (midcarpal) aspect, and 43 lunates of Type II (55.1%), i.e., having two facets on this aspect. Chondral defects and/or arthritic lesions of the ulnar portion of the midcarpal joints were observed in 22.8% of Type I lunates and in 30.2% of Type II lunates. Chondral lesions of the midcarpal joints in Type I lunates were always associated with other ligamentous and/or osteochondral lesions, whereas the same lesions could be found isolated in Type II lunates. The observed association of lesions seemed to point to a trauma as the cause of some chondral lesions. The results of our clinical study were compared with anatomical studies by Viegas, all which showed no hamate pathologic conditions in Type I lunates.