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Use of Standing MRI and a New MRI Grading System of the Subchondral Bone of the Distal Third Metacarpal Bone to Identify Bone Changes in the Thoroughbred Racehorse When Comparing 21 Cases of Catastrophic Biaxial Proximal Sesamoid Bone Fracture with 53 Controls
Author(s) -
Peloso J.G.,
Vogler J.B.,
Cohen N.D.,
Marquis P.,
Hilt L.
Publication year - 2014
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.12323_56
Subject(s) - fetlock , medicine , sesamoid bone , subchondral bone , metacarpal bones , lameness , surgery , osteoarthritis , radiography , articular cartilage , pathology , alternative medicine
Reasons for performing study Biaxial fracture of the proximal sesamoid bones ( PSB ) is the leading cause of fetlock failure resulting in euthanasia in Thoroughbred racehorses in C alifornia, K entucky and H ong K ong. Identifying alterable risk factors to reduce biaxial PSB fractures could have a significant impact on reducing the occurrence of catastrophic failure of the fetlock ( CFF ). Objectives We hypothesised that standing MRI (s MRI ) would identify a greater degree of bone change in Thoroughbred racehorses with CFF from biaxial PSB fracture when compared to controls. Study design Retrospective cohort study. Methods Bone changes from F lorida Thoroughbred racehorses with CFF due to biaxial fracture of the PSB (n = 21) were compared to controls (n = 53) using the s MRI . Data for control limbs were F lorida racehorses that were subjected to euthanasia for reasons other than CFF (enteritis, pneumonitis, etc.). All forelimb fetlocks underwent s MRI imaging within 72 h of euthanasia. Bone scores were assigned to the subchondral bone ( SCB ) on the distal palmar aspect of the lateral and medial condyle of the third metacarpal bone ( McIII ) and the lateral and medial PSB . All information for analysis from s MRI images for cases and controls for all Thoroughbred racehorses was reviewed and collected by the lead author. The association between the dichotomous outcomes of PSB fracture with independent variables was assessed using bivariable and multivariable logistic regression analysis with significance set at P<0.05. Results The proportion of cases with >75% sclerosis of the ipsilateral lateral PSB (43%, 9/21) was significantly greater than that among controls (6%, 3/53). The proportion of cases with SCB lesion grade >3 of the contralateral palmar lateral condyle (29%, 6/21) was significantly greater than that among controls (0%, 0/53). Conclusions The s MRI identified a significantly greater degree of bone change in racehorses with PSB fracture compared to control horses. These identified changes may be useful as a screening tool to identify horses at increased risk of fetlock fracture during racing. Ethical animal research: Explicit owner informed consent for participation in this study was not given but permission for post mortem examination was given by the Racing Authority. Sources of funding: None. Competing interests: No competing interests have been declared.