findings of extensive hyperintensity on T2* gradient echo and short tau inversion fast spin echo sequences and corresponding hypointensity on T1 gradient echo images within the palmaroproximal aspect of the third metacarpal bone. Follow-up information was available for all cases; at the time of writing 7/8 had returned to full work and were free from lameness. Conclusions: The BMO-type signal patterns visible on MR images in these cases may signal the existence of a previously under-diagnosed pathological process associated with proximal metacarpal lameness in racehorses. This finding is postulated to be associated with a stress reaction and possible prodromal stress fracture of the palmaroproximal metacarpus not appreciable radiographically or ultrasonographically. Potential relevance: MRI of the proximal metacarpal region permits detection of pathological processes, which may elude conventional imaging and, therefore, has important therapeutic and prognostic implications in these cases.

Clinicians should be aware that US abnormalities of the SLB may not always be related to clinical desmopathy. Further longitudinal studies are required to determine whether such findings are predictive for future injury.

Sagittal fracture of the proximal phalanx (P1) is an important musculoskeletal injury of the performance horse. Although widely considered to be monotonic in nature, there is emerging evidence that some P1 fractures may have stress-injury aetiology. Three cases are described in which imaging features found were suggestive of prodromal bone injury. All cases returned to full performance use after a period of rest. The authors conclude that it is possible that some P1 fractures in the Thoroughbred racehorse may develop through stress/fatigue injury pathways. It is proposed that intervention prior to overt fracture may be possible in some cases.

No abstract

Clinical findings associated with unicortical condylar fractures can be mild and appropriate diagnostic imaging is necessary for injury detection. Failure to detect injury can lead to catastrophic fracture. Most cases respond to conservative management and return to racing, but risk of reinjury merits consideration of surgery in selected cases. Veterinary vigilance and timely intervention has the potential to considerably reduce the incidence of complete condylar fracture of the fetlock in the racehorse. The Summary is available in Chinese - see Supporting information.