Study: Lamenesses Might Not Originate From Where You Think

Study: Lamenesses Might Not Originate From Where You Think

Horse owners should pay close attention to signs of lameness, but also be aware that the leg that appears to be lame may not be the leg that is the source of the problem, Maliye said.

Photo: Erica Larson, News Editor

You know your horse is lame. (He is lame, right?) And you think the left forelimb is the culprit. (Maybe? Who knows!)

Localizing a lameness can be challenging for even the most experienced equestrians and veterinarians. And just when you think you’ve got it down pat, researchers find new information that could add another point of consideration to lameness exams. For instance, recent research has revealed that what appears as lameness might actually just be a reaction that compensates for pain in another foot or leg—specifically, some horses can appear lame in the front limb when the real lameness is the hind-limb on the same side.

“Horse owners should pay close attention to signs of lameness, but also be aware that the leg that appears to be lame may not be the leg that is the source of the problem,” said Sylvia Maliye, BSc, BVM&S, of the University of Glasgow’s School of Veterinary Medicine Weipers Centre Equine Hospital, in Scotland.

“Previous research has revealed that observers find accurate identification of forelimb lameness easier than hind-limb lameness,” she said. “Correctly identifying the lame hind limb is more challenging. To successfully treat the horse with hind-limb lameness, it is essential to correctly identify the limb with the primary problem. Sometimes two legs appear lame (a forelimb and a hind limb), but there is only pain in one leg.”

In their three-year study, Maliye and senior researcher John F. Marshall, PhD, BVMS, also of the University of Glasgow, analyzed 37 horses with hind-limb lameness at the university clinic. Among the horses selected for the study, 19 had hind-limb lameness alone, 10 had lameness in both legs of a single side (ipsilateral limbs), and eight had one lame hind-limb and a lame forelimb on the opposite side of the lame hind limb (contralateral limbs).

They found that the horses with ipsilateral limb lameness, as determined by inertial sensor analysis, improved when the hind limb alone was anesthetized, Maliye said.

“A proportion of horses with hind-limb lameness can give the observer the impression that they also have an ipsilateral forelimb lameness,” she said. “This is not a true lameness, but is due to the horse attempting to ‘off-load’ the lame hind limb by altering its head position.”

However, that was not true of the horses with contralateral front limb lameness, she added. If the horse had diagnosed lameness in the hind limb and showed lameness in the opposite front limb as well, that front limb lameness did not improve when the hind limb was anesthetized.

Maliye’s and Marshall’s previous study revealed that horses with a true forelimb lameness will not properly “push off” with their contralateral hind limb and can appear lame in that hind limb. In other words, the back leg might appear lame if the opposite front leg is truly sore, but the front leg won’t appear lame just because the opposite back leg is sore, she said.

“We found no evidence in our small study to show that contralateral forelimb lameness in horses with hind-limb lameness was compensatory,” Maliye told The Horse. “Horses presenting with this may have a true forelimb lameness alongside a true hind-limb lameness.”

So what should owners of lame horses do? Maliye said that when it comes to lameness, nothing beats a combination of close observation, experience, and technology.

“It is best to rely upon experienced veterinarians and high-tech equipment such as inertial sensor-based systems that can provide objective information about lameness and asymmetry,” she said. “It is essential to view the entire horse and observe any asymmetry carefully before deciding upon which limb to focus the investigation on. Veterinarians should thus keep their initial assessment broad and examination thorough. Reassessment of both forelimb and hind-limb lameness is required throughout the lameness investigation, as symmetry of the pelvis and head movement can sometimes both markedly change after one nerve block.

The information gleaned from the recent study can help veterinarians know where to start.

"Clues such as the severity of lameness in a specific limb, physical examination findings, positive response to flexion tests, along with knowledge of this pattern of compensation ("rule of sides") can help the veterinarian commence nerve blocking on the primarily lame limb," she said.

The study, “Objective assessment of the compensatory effect of clinical hind limb lameness in horses: 37 cases (2011–2014),” was published in the Journal of the American Veterinary Medical Association

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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