Does arelation between bone histomorphometry and fractures exist? The case ofthe equine radius and tibia.

Abstract

Fractures oflong bones inlimbs are rare traumatic events inhorses. This study investigates whether theincidence and types offractures can berelated tothe histomorphometric features ofthe radius and tibia, which experience different biomechanical stresses and exhibit varying incidences and types offractures. Clinical observations suggest that, inadults, slightly transverse and comminuted fractures are present inthe radius, while thetibia shows ahigher frequency oflongitudinal and spiral fractures. Microscopic observations reveal noapparent distinctive characteristics between the radius and tibia, whereas the histomorphometric data highlight differences inthe osteon density, eccentricity, and diameters ofthe osteons and Haversian canals. Tosum up, tibial osteons are more numerous and smaller than those inthe radius, resulting ina15% higher total extension ofthe cement line inthe tibia compared tothe radius. These histomorphometric differences are anevolutionary adaptation tothe different biomechanical stresses that involve the thoracic and pelvic limbs. Our results could help better understand numerous clinical realities detectable through retrospective analyses and aid inevaluating aspecific bone's predisposition towards traumatic events inall mammals, including humans.