Slab fracture of the third tarsal bone
3 year old Standardbred male
History
A 3 year old Standardbred male was referred for right hind limb lameness of unknown origin. The horse was found lame the day next to routine training and the referral vet performed a complete clinical examination, including several diagnostic blocks from the distal limb to stifle joints. In the absence of any positive response to blocks and of any localized swelling or painful response to palpation, the horse was treated with phenylbutazone 4 g/day for five days. No improvement was noticed and the horse was referred for scintigraphy.
Scintigraphy
The horse was administered 6500 MBq Technetium 99 MDP and a bone phase scintigraphic examination was performed 3 hours later. A complete scanning was peformed, including plantar views of the distal limbs and hocks, lateral views of distal limbs, hocks and stifle, and dorsal view of the pelvis. A significant increase of the radionuclide uptake was visible on the dorsolateral aspect of the distal tarsal joints of the right side (Fig. 1). A lesion affecting the distal intertarsal and tarsometatarsal joints was suspected.
Radiology
A complete examination of the affected area was performed with 5 radiographic views (Dorsoplantar, Lateromedial, Dorsolateral-Plantaromedial Oblique, Plantarolateral-Dorsomedial Oblique, Flexed Lateromedial). A complete slab fracture of the third tarsal bone was well visible on the Plantarolateral-Dorsomedial Oblique view (Fig. 2).
Surgical treatment
The horse was positioned under general anesthesia in lateral recumbency with the right side uppermost. The dorsolateral aspect of the tarsal and proximal metatarsal region was aseptically prepared. After a 6 mm incision, a cortical 4.5 mm screw was inserted in lag fashion under radiographic control. Intraoperative radiographic control confirmed the correct position of the screw and reduction of the fracture (Fig. 3).
Follow up
After 6 weeks rest, the horse started regular training. Six months after surgery, the horse returned to racing and raced 26 times, with 7 wins and 10 places, and improved his life time record from 1.16.6 to 1.14.4