The application of a scintigraphic grading system to equine tibial stress fractures: 42 cases.

Reasons For Performing Study: Tibial stress fractures are an important cause of lameness in the Thoroughbred racehorse. While it is recognised that these injuries can vary in clinical presentation and radiographic or scintigraphic appearance, little has been done to quantify lesion severity. By contrast the scintigraphic grading of tibial stress fractures in human athletes is widely reported and assists in the selection of appropriate management regimes.

Objectives: To determine the relationship between scintigraphic grade, clinical severity and radiographic appearance of tibial stress fractures.

Methods: The current study involved the retrospective analysis of records from 42 Thoroughbreds with abnormal tibial scintigraphic activity.

Results: There was a significant association between lesion site and scintigraphic grade and good correlation of scintigraphic scoring between investigators. No significant association was found between scintigraphic grade and either radiographic grade or degree of lameness.

Conclusions: The study confirmed that radiographic appearance is an unreliable measure of clinical severity or stage of progression of lesions. The scintigraphic grading system used in the study was not of use in defining stress fracture severity in the equine tibia.

Potential Relevance: Despite this finding, there is clearly a need for prospective investigations to explore the potential for targeted management regimes for tibial injuries based on lesion site or clinical criteria.