Dual-energy X-ray absorptiometry measurement of bone-mineral density in the distal aspect of the limbs in racing Greyhounds

Objective-To determine those bones in the distal aspect of the limbs of Gre yhounds with fatigue fractures that have the greatest left-to-right differe nces in bone-mineral density (BMD). Sample Population-Limbs obtained from 20 Greyhounds. Procedure-Dual-energy x-ray absorptiometry (DXA) of the distal aspect of ea ch limb and isolated bones from 10 dogs with a fracture of the central tars al bone (CTB) of the right pelvic limb was performed. High-resolution scann ing was performed on excised bones, and BMD measurements of CTB also were o btained from Limbs of dogs without a CTB fracture. Results-The BMD of the accessory carpal bone and calcaneus was not signific antly different from the BMD of those bones in the contralateral limb. Alth ough BMD of the CTB of the entire right pelvic limb and isolated bones from dogs with a CTB fracture was lower, compared with values for the entire le ft pelvic limb, Values for isolated CTB from dogs without a CTB fracture we re not significantly different. Metacarpal or metatarsal and thoracic or pe lvic limb significantly affected BMD for measurements of the entire limb an d isolated bones. Left-to-right differences in BMD were greatest for metaca rpal 5. Conclusions and Clinical Relevance-Asymmetric adaptive remodeling of metaca rpal 5 can be detected by DXA. The potentially confounding effects of CTB f racture and unknown racing history made it difficult to interpret BMD chang es in the CTB of these specimens. Densitometry could be developed as an in vivo assessment for risk of fractures in racing Greyhounds.