Kienböck's Disease; the Length of Capitate and Third Metacarpal Bones

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.
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 .
The study compared the wrist posteroanterior (PA) X-ray 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 X-ray. The Lichtman classification was used for staging. A new index, named capitate-index, was defined due to the linear relationship between the capitate and the third metacarpal lengths.
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 capitate-index (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 Based on the above-mentioned findings, the existence of a relationship between the third metacarpal and the capitate lengths and the Kienböck’s disease is unlikely.