Incomplete fracture of the talus secondary to maladaptive stress remodeling in a horse.

This research article investigates the case of a horse with a non-weight-bearing lameness of the hind limb following rigorous activity, which was revealed to be due to an incomplete talus fracture and signs of maladaptive stress remodeling. The horse was successfully treated through non-surgical methods and returned to its previous performance level within about a year.

Background

• The study was prompted by a 6-year-old Quarter Horse gelding, a barrel racing horse, that was observed to have an acute onset of non-weight-bearing lameness in the left hind limb after intense exercise.

Diagnostic Procedures and Results

• The horse underwent nuclear scintigraphic imaging, which showed an increased radiopharmaceutical uptake centrally within the left talus. The talus is one of the bones in the hock, or tarsus, of a horse, which is the equivalent of the human ankle.
• Further tests using standard radiographic and ultrasonographic examinations could not identify the reason for this increased uptake, but anesthesia localized the lameness to the tarsocrural joint.
• MRI sequences revealed the existence of an incomplete fracture in the talus, extending distally from the trochlear groove. Also, there was evidence of maladaptive stress remodeling in the trochlear groove of the talus and the distal intermediate ridge of the tibia.

Treatment and Recovery

• The gelding horse was managed non-surgically through stall confinement, regular physical rehabilitation, therapeutic laser therapy, and administration of intra-articular autologous conditioned serum.
• After 15 months of this treatment routine, the horse’s lameness had resolved, and it was performing on the same level as before the onset of lameness.

Implications

• The study suggests that an incomplete fracture of the talus, although rare, should be considered when treating horses with acute hind limb lameness following strenuous exercise.
• Especially if the exercise involves horses making sudden directional changes at high speed, the possibility of such a fracture should not be overlooked.
• Acquiring additional oblique projections of the tarsus during radiographic evaluation may aid in identifying such fractures. However, advanced diagnostic imaging modalities like CT and MRI may be necessary for definitive diagnosis.
• The study also points out that horses with incomplete fractures of the talus can be successfully managed through conservative treatment methods.