The Rundown on Equine Shoulder Sweeney

Horses are remarkably active animals that make good use of their limbs and joints as they canter, gallop, and trot. As such, it is important that owners are cognizant of their horse’s health and of potential conditions that might arise.

Three horses in a fieldDr. Jeffrey Watkins, a professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, weighs in on shoulder Sweeney, also known as suprascapular neuropathy, a condition affecting the nerves and muscles of a horse’s shoulder region.

“Shoulder Sweeney refers to an injury of the suprascapular nerve, which runs over the front part of the scapula and provides the nerve supply to two major muscles that support the shoulder joint,” Watkins said. “When the nerve is injured, these muscles are unable to function normally and will undergo atrophy, which can occur very rapidly.”

This condition presents in two forms, chronic and acute, according to Watkins.

The chronic form of shoulder Sweeney was once common in horses that often pulled heavy loads, such as wagons and farm equipment, and was attributed to repetitive nerve injury often associated with ill-fitting harness collars.

In these chronic cases, clinicians typically find significant atrophy of the two major muscles that are supplied by the nerve overlying the scapula, and when these muscles atrophy, the bony spine of the scapula becomes very prominent.

Chronic shoulder Sweeney has become less frequent, as workhorses are less common.

“What we see today, most of the time, is a much more acute injury,” he said. “Usually, it’s because the horse is running fast and hits something immovable, another horse or a fence post, very forcefully with the point of their shoulder.”

This impact causes an acute nerve injury that results in dysfunction of the two major muscles noted above.  These muscles are responsible for maintaining the lateral stability of the shoulder joint and when they lose their nerve supply acutely, the shoulder region becomes unstable.

Watkins said it is important to consider other potential conditions that can occur secondary to a high-impact injury to the shoulder region. An examination by a veterinarian, including high-quality radiographs of the shoulder region, is necessary to rule out other injuries, such as a fracture.

Shoulder Sweeney is usually diagnosed by observing the gait of the horse and tends to be straightforward.

“They have a very characteristic gait where whenever they try to put weight on their leg, their shoulder joint partially dislocates to the outside,” Watkins said. “These horses don’t walk well; they have a very obvious gait abnormality that basically makes them unusable in the short-term.”

Though this condition can significantly impact a horse’s function in the short term, the good news is that most horses suffering from an acute shoulder Sweeney will recover stability in that joint over time and will be able to function normally again. But the process requires rest and patience.

“It’s important to recognize it can take quite a long time for that nerve to heal and to basically regrow,” Watkins said. “We usually say it will take six to eight months for that nerve to begin to regain function and for that shoulder to stabilize and no longer have issues.”

Although most horses recover their ability to move normally, atrophy of the muscles overlying the shoulder blade will usually be permanent and the horse will have the characteristic boney protrusion of the shoulder area associated with shoulder Sweeney for the remainder of its life.

Pet Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the web at vetmed.tamu.edu/news/pet-talk. Suggestions for future topics may be directed to editor@cvm.tamu.edu.

What to Know About Equine Osteoarthritis

Osteoarthritis is a progressive disease that compromises the joint health and mobility of many animals. While osteoarthritis is the most common joint disorder for people in the United States, the condition is also prevalent in horses.

Dr. Jeffrey Watkins, a professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, provides insight into equine osteoarthritis and how owners might manage this condition in their horses.

“Osteoarthritis refers to deterioration of a joint or joints that is characterized by progressive loss of cartilage,” Watkins said. “The inflammation associated with osteoarthritis causes pain and swelling of the affected joints.”

Cases of osteoarthritis can be divided into two groups: primary and secondary.

Primary osteoarthritis arises from the wear and tear of everyday activities, resulting in a slow breakdown of joint cartilage. Performance horses are at particular risk for this form of osteoarthritis.

“Often, the first indication of a problem is a change in the horse’s behavior, willingness to perform, and/or ability to perform at their expected level,” Watkins said. “These are often subtle indications of a developing joint problem and are due to the low-grade pain associated with the insidious onset of osteoarthritis.”

Secondary osteoarthritis comes when an injury to a joint is severe enough to begin the process of cartilage breakdown. Horses with a history of joint infections, fractures involving the joint, ligament and tendon injuries, and preexisting joint defects are at risk for secondary osteoarthritis.

“Osteoarthritis secondary to an injury or infection will be characterized initially by the signs associated with the inciting injury. Once the initial injury has been resolved, osteoarthritis is manifested as continued loss of function due to pain and stiffness of the affected joint,” Watkins said.

If an owner suspects that their horse might be suffering from osteoarthritis, they should contact their veterinarian, who might conduct a physical evaluation and lameness examination, as well as recommend diagnostic imaging such as radiography, ultrasonography, computed tomography (CT), or magnetic resonance imaging (MRI).

Prevention of equine osteoarthritis varies depending on the type. For secondary osteoarthritis, prompt and proper treatment of the initial joint injury is vital. Primary osteoarthritis is more complicated, involving many factors including proper hoof care, responsible training regimens, and the monitoring of any predisposing factors.

“Management of osteoarthritis is a multifaceted approach and includes modification of the affected horse’s activity level, attention to body weight and body condition, appropriate hoof care, medical therapy, and surgical therapy,” Watkins said.

As with all conditions, owners concerned for their horse’s health should consult with their veterinarians to establish an individualized management strategy. Luckily, research into osteoarthritis management is ongoing, so we might one day see options for complete rehabilitation.

Pet Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the web at vetmed.tamu.edu/news/pet-talk. Suggestions for future topics may be directed to editor@cvm.tamu.edu.