Radiological investigation of relationship between lunate type and ulnar variance

Some variances and anatomical proportions of the wrist may contribute to development of avascular necrosis of the lunate. Kienböck's disease is more often encountered in young males, who suffer, among others, from type II of the lunate (with two joint surfaces for the capitate and hamate) and/or negative variance of ulna in relation to radius. The aim of the study was to investigate whether there exists interdependence between the simultaneous occurrence of individual types of the lunate with one of the variances of ulna in both genders.

A retrospective analysis of 394 (n=394) radiological tests of the wrist in 174 (44%) women and 220 (56%) males aged 18-83 years (average age 39 years). From the entire pool, 265 X-rays were educed in 104 females and 161 males, and no fractures or wrist instability features were could be observed. The X-rays were obtained from computer lab and archive data base at St Hedwig Hospital in Trzebnica from the beginning of January 2011 to the end of December 2012.

196 cases (74%) were found with type I of the lunate and 69 cases (26%) with type II. Ulnar variance amounted to from +4.7 mm to -4.2 mm (mean value +0.9 mm). Positive ulnar variance was stated in 44 patients (16.6%), negative in 63 (23.7%) and neutral accounted for the biggest group of other 158 (59.7%) patients.

Neutral variance of ulna is the one that occurs most often in the Polish population. There is no correlation between gender and ulnar variance. There is also lack of direct connection between occurrence of individual lunate types and ulnar variance.