Radiographic Fetlock Abnormalities in Barrel Racing Horses
Menarim said monthly vet checks can help detect injury early and allow prompt treatment. Further, he said, proper hoof care and the use of support boots could help prevent excessive fetlock hyperextension, which could lead to injury.
Think high-performance barrel racers need a clean set of X rays to bring home blue? Think again. A team of South American researchers recently completed a study that showed nearly 50% of barrel racing horses could be performing with radiographic changes in their fetlock joints.
"Barrel racing is one of the most popular uses of the American Quarter Horse in North and South America," explained Bruno Carvalho Menarim, DVM, MS, a veterinarian in the Department of Clinical Sciences at the Universidad Austral de Chile, in Valdivia.
"Although injury to the metacarpophalangeal (fetlock) joint frequently occurs in this sport, there is little information describing the nature of these injuries," Menarim said. "The aim of this study was to determine the most common radiographic abnormalities in barrel racing horses with lameness referable to the metacarpophalangeal joint."
Menarim and colleagues evaluated 63 barrel racing Quarter Horses in "intensive training and performing barrel racing competitions" that:
- Were at least 3 years old;
- Were lame at the walk and/or trot before and/or after a fetlock flexion test;
- Underwent a thorough lameness examination; and
- Underwent a complete fetlock radiographic evaluation.
Of the 63 horses evaluated, 30 (ranging in age from 3 to 19 years, four of which were "spontaneously lame" and 26 of which were only lame after flexion) met the aforementioned criteria and were included in the study.
Menarim et al. found that of the four horses with spontaneous lameness, one had bilateral (on both sides) lameness and three had unilateral lameness (one was lame on his right front leg while the other two were lame on their left forelegs). Additionally, of the 26 horses lame after flexion, 10 were lame unilaterally (seven on the right front leg and three on the left) and 20 were lame bilaterally.
Menarim also noted that the team found "radiographic evidence of disease" in 29 of 30 (96.8%) study horses' fetlocks. Common radiographic abnormalities identified and their prevalence included:
- Sesamoiditis (inflammation associated with the proximal sesamoid bones, which are two small bones sitting at the base of the cannon bone in back of the fetlock joint) in 70% of horses;
- Villonodular synovitis (inflammation and/or fibrosis, or scarring, of the synovial pad on the front of the fetlock due to repeated trauma and extreme extension of the joint) in 56.6% of horses;
- Osteoarthritis from bone spur, or osteophyte, formation in 36.6% of horses;
- Osteochondral fragments, or bone chips, in 13.3% of horses;
- Capsulitis (joint capsule inflammation) in 13.3% of horses; and
- Generalized soft tissue swelling in 6.6% of horses.
Menarim noted that, according to previous research, "the majority of these radiographic abnormalities suggest injury caused by (fetlock) joint hyperextension."
The research team also collected follow-up information on 27 of the 30 study horses for 12 months after the initial examinations. The team learned that:
- After 12 months 23 horses were still actively competing;
- Ten horses that were lame after flexion were in the Top 10 in their respective classes, and six won classes at the following year's National Barrel Racing Championships (the overall barrel racing champion for the year exhibited a Grade 4 out of 5 lameness after flexion during the study); and
- Four horses had been retired by 12 months after the study; only one of the four was retired due to fetlock lameness.
Menarim noted that, in the 12 months following the evaluations, 11 of the 30 horses remained under the researchers' care; eight of those horses received musculoskeletal injury treatment including:
- Stall rest (8 horses);
- Oral non-steroidal anti-inflammatories (8 horses);
- Topical anti-inflammatories (7 horses);
- Intra-articular (in the joint) steroid injections (6 horses);
- Intra-articular sodium hyaluronate injections (3 horses); and
- Annular ligament desmotomy, a procedure that involves severing the annular ligament, which holds the superficial and deep digital flexor tendons in place as they pass the fetlock (1 horse).
He also noted that nine of the 11 horses under the researchers' care received corrective shoeing in the 12 months following the evaluation.
Although nearly 50% of the barrel racing Quarter Horses evaluated had radiographic abnormalities of the fetlock joint, many of these horses continued on as high-performance athletes, Menarim concluded, noting that the same is true for many equine competitors regardless of discipline.
"This indicates that in high performing barrel racing horses some degree of lameness after flexion, even associated with radiographic abnormalities of the fetlock joint, may not be completely detrimental to performance ability,"said Menarim.
He also offered some advice for barrel racing and other performance horse owners: "Monthly veterinary check-ups for high-performance barrel racers increase the possibility of early diagnosis of musculoskeletal injury and, therefore, the odds to have a successful treatment to extend the horse´s career. Adequate hoof care and use of support splints (boots) could be helpful to preventing excessive hyperextension."
He also stressed that "the attending veterinarians should always perform a thorough clinical exam and discuss potential athletic incapacitities with owners when abnormalities are found during the radiographic exam, and be careful to state athletic incapacity when abnormalities are found at the radiographic exam. Radiographic abnormalities are easily found in competitors of any sport horse discipline able to ... compete (at a high level)."
The study, "Radiographic Abnormalities in Barrel Racing Horses with Lameness Referable to the Metacaropophalangeal Joint," appeared in April in the Journal of Equine Veterinary Science (doi:10.1016/j.jevs.2011.09.064). The abstract can be viewed online.
About the Author
Erica Larson, news editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.
POLL: Colic Surgery