Vet Comp Orthop Traumatol 2019; 32(S 03): A1-A12
DOI: 10.1055/s-0039-1692238
Podium Abstracts
Georg Thieme Verlag KG Stuttgart · New York

Evidence of Subchondral Lesions Preceding Proximal Sesamoid Bone Fracture in Thoroughbred Racehorses

S.K. Shaffer
1   Mechanical and Aerospace Engineering, University of California, Davis, Davis, California, United States
,
D.P. Fyhrie
2   Dept. Orthopaedic Surgery, School of Medicine, University of California, Davis, Davis, California, United States
,
S.M. Stover
3   School of Veterinary Medicine, Department of Anatomy, Physiology, and Cell Biology, University of California, Davis, Davis, California, United States
› Author Affiliations
Further Information

Publication History

Publication Date:
17 May 2019 (online)

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    Introduction: Proximal sesamoid bone (PSB) fractures are the leading cause of racehorse death. Our objective was to determine if PSB abnormalities precede fracture.

    Materials and Methods: Fractured (FX) and intact contralateral (CIL) medial PSBs from 10 thoroughbred racehorses that died because of a unilateral biaxial PSB fracture and a medial PSB (CTRL) from 10 TB racehorses that died for an unrelated reason were initially studied. Color abnormalities and focal radiolucencies (lesions) were quantified using articular surface, parasagittal serial sections, or radiographs. Focal bone porosity was determined from microcomputed tomography (µCT) images of a second sample of PSBs (9 FX, 9 CIL, 18 CTRL).

    Results: Focal subchondral discoloration was observed in 10% of CTRL, 70% of CIL, and 80% of FX PSBs; and on the fractured face of 90% of FX-PSBs. Subchondral lesions were observed in 0% of CTRL, 50% of CIL-PSBs, and 60% of FX-PSBs. Subchondral discoloration and subchondral lesions were highly correlated (r = 0.711); 69% of discolored samples had a subchondral lesion. Bone porosity was 12% higher at the subchondral lesion site in FX-PSBs and 2% higher in CIL-PSBs than in CTRLs.

    Discussion/Conclusion: Focal subchondral lesions of high porosity were present in fractured PSBs and to a lesser extent in contralateral intact PSBs and were rare in control PSBs; these lesions likely predispose to PSB fracture.

    Acknowledgment: Supported by the Grayson Jockey Club Research Foundation and the Center for Equine Health with funds provided by the State of California satellite wagering fund and contributions by private donors.


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    No conflict of interest has been declared by the author(s).