Kienböck’S Disease; the Length of Capitate and Third Metacarpal Bones

Background the relationship between negative ulnar variance and kienböck’s disease is unknown and does not justify all of the cases. the present study planed the hypothesis that maybe the pressure from distal structures to the lunate bone plays a role in the etiology. objectives the current study aimed to investigate the possibility of a relationship between an increased length of the third metacarpal and the capitate with kienböck’s disease . methods the study compared the wrist posteroanterior (pa) xray images of 105 healthy individuals with those of 91 patients with kienböck’s disease . meticulous measurement criteria were defined in the present study to measure the third metacarpal and the capitate lengths. these lengths along with ulnar variance were measured on each xray. the lichtman classification was used for staging. a new index, named capitateindex, was defined due to the linear relationship between the capitate and the third metacarpal lengths. results comparing the two groups, no meaningful difference was observed between the capitate and third metacarpal bone lengths in patients and the control group. also, there was no significant difference in the capitateindex (capitate length/3rd metacarpal length) between the groups. furthermore, no differences were observed comparing the patients with ulnar variance ≧ 0 and patients with ulnar variance < 0 to the control group regarding the above parameters. the only significant difference was a higher negative ulnar variance among the patients with kienböck’s disease . conclusions based on the abovementioned findings, the existence of a relationship between the third metacarpal and the capitate lengths and the kienböck’s disease is unlikely.