- Veterinary View Box
- Posts
- Can Ultrasound Detect Early Humeral Fractures in Racehorses? New Study Says Yes
Can Ultrasound Detect Early Humeral Fractures in Racehorses? New Study Says Yes
Equine Vet Journal 2025
Obi Veterinary Education
August 03, 2025
Betsy Vaughan, Erin R. McKerney, Carolyn Wollenberger, Ashton Cloninger, Mathieu Spriet, Larry Galuppo, Susan M. Stover
Background
Caudoproximal humeral stress fractures in Thoroughbred racehorses pose a significant risk for catastrophic failure if undiagnosed. Scintigraphy is the current gold standard but is limited by cost and accessibility. Radiography often lacks early sensitivity. This study investigates ultrasonography as a viable diagnostic alternative for detecting humeral stress fractures.
Methods
Seven Thoroughbred racehorses aged 2–4 years with acute severe forelimb lameness underwent clinical evaluation from 2013 to 2021. All received humeral ultrasonography and radiography, with five also undergoing scintigraphy. Diagnostic imaging findings were compared, and horses were followed longitudinally via repeat imaging and performance outcomes.
Results
Ten caudoproximal humeral stress fractures were identified. Ultrasonography detected 9 of 10 fractures, revealing step defects, periosteal roughening/callus, or convex cortical contours. Radiographs confirmed periosteal and/or endosteal proliferation in most cases but missed some early lesions. Scintigraphy detected additional remodeling in select cases not seen via other modalities. Recheck imaging showed remodeling over time, and six of seven horses returned to athletic activity, including four to racing.
Limitations
The study included a small number of Thoroughbreds with known or suspected humeral stress fractures. Ultrasonography was limited to the caudoproximal humerus, and not all imaging modalities were applied in every case. Broader applicability to other breeds or stress fracture sites was not assessed.
Conclusions
Ultrasonography is a practical, early diagnostic tool for identifying caudoproximal humeral stress fractures in racehorses. It can complement or substitute more advanced imaging in resource-limited settings and guide rehabilitation monitoring. Bilateral imaging is advised due to potential subclinical contralateral involvement.
Affected humerus in a 3-year-old mare. (A) Radiography—mediolateral image taken of the affected limb extended cranially and proximally illustrates callus formation (arrow) along the caudal aspect of the humerus with endosteal sclerosis. (B) Nuclear scintigraphy—lateral image of the affected left humerus illustrates focal marked radiopharmaceutical uptake (arrow) at the caudoproximal site of the stress fracture. (C) Caudolateral ultrasonographic image of the fracture illustrates a step defect and callus formation (arrow). Proximal is at the top and caudal is to the right of the image. (D) Postmortem specimen (obtained from a horse outside of this study) illustrates the callus and convex contour (arrow) of the caudal aspect of the neck of an affected humerus.
How did we do? |
Disclaimer: The summary generated in this email was created by an AI large language model. Therefore errors may occur. Reading the article is the best way to understand the scholarly work. The figure presented here remains the property of the publisher or author and subject to the applicable copyright agreement. It is reproduced here as an educational work. If you have any questions or concerns about the work presented here, reply to this email.