Linear intra-bone geometry dependencies of the radius: radius length determination by maximum distal width.

PURPOSE: The aim of the study was to investigate possible linear intra-bone geometry dependencies by determining the relation between the maximum radius length and maximum distal width in two independent populations and test for possible gender or age effects. A strong correlation can help develop more representative fracture models and osteosynthetic devices as well as aid gender and height estimation in anthropologic/forensic cases.
METHODS: First, maximum radius length and distal width of 100 consecutive patients, aged 20-70 years, were digitally measured on standard lower arm radiographs by two independent investigators. Second, the same measurements were performed ex vivo on a second cohort, 135 isolated, formalin fixed radii. Standard descriptive statistics as well as correlations were calculated and possible gender age influences tested for both populations separately.
RESULTS: The radiographic dataset resulted in a correlation of radius length and width of r=0.753 (adj. R(2)=0.563, p<0.001) with sex having a significant (p=0.005, adj. R(2)=0.592) and side no influence on the correlation. Radius length-width correlation for the isolated radii was r=0.621 (adj. R(2)=0.381, p<0.001) with sex significantly influencing this correlation (p<0.001, adj. R(2)=0.598).
CONCLUSION: A relatively strong radius length-distal width correlation was found in two different populations, indicating that linear body proportions might not only apply to body height and axial length measurements of long bones but also to proportional dependency of bone shapes in general.