Osteoarthritis is the leading cause of lameness in performance horses and can lead to long-term pain, inflammation, and reduced performance. Currently, no cures for equine joint disease exist, and horses with osteoarthritis need lifelong management. Scientists have found that pulsed electromagnetic field therapy (PEMF) improves bone remodeling and healing, chronic inflammation, and tissue repair in humans. But its potential in equine medicine remains largely unexplored, and no standardized protocols exist, said Isla Wilson, a student in the laboratory of Carleigh Fedorka, PhD, at Colorado State University, in Fort Collins. Wilson presented her work at the 2025 Equine Science Society Symposium, held June 3-6, also in Fort Collins.

“The goal of our study was to assess the efficacy of a single (PEMF) treatment on reducing lameness in horses with osteoarthritis,” said Wilson. She and her fellow researchers studied six middle-aged Thoroughbred mares that all received the same PEMF treatment and were assessed for lameness at different time points following treatment. They treated each mare on a power level of 2 (on Magnawave’s machine) for 30 minutes, which was the highest setting and longest duration they would tolerate.

PEMF’s Effects on Equine Lameness and Inflammation

A veterinarian blinded to treatment status performed subjective lameness examination one hour, one day, and one week after treatment. At the same time points Wilson and her team performed an objective lameness assessment using inertial sensors. Additionally, she noted, at those time points they collected blood to test cytokine (markers of inflammation) concentrations.

The veterinarian performing the subjective lameness exam noted an improvement in the mares’ lameness scores one hour after treatment but little to no improvement at one day or one week. However, using the objective assessment, Wilson said she and her team saw no improvement in asymmetry scores in any of the mares following treatment. “The objective assessment only detects movement on one plane, so that could play a role in the discrepancy,” she added.

The team noticed a decrease in four blood cytokines one hour after PEMF treatment, but these began to increase after one day and returned to baseline or higher by one week.

Take-Home Message

A single PEMF treatment might have the ability to reduce pain and inflammation in horses with osteoarthritis up to one hour after treatment, but the effects dissipate from one hour to one day after treatment. “Our study highlights the need for continued standardization of PEMF treatments to enhance outcomes,” said Wilson. She hopes her future research will help veterinarians and PEMF practitioners know how many treatments it takes to reduce or eliminate pain and inflammation in horses with osteoarthritis.