Stem Cells for Navicular

Traditional stem cell treatments contain living cells, which can be laborious (expensive) to prepare and can have negative side effects when injected into synovial structures like the navicular bursa.

This laboratory experiment, conducted by Ohio State University researchers, examined the anti-inflammatory and protective potential of extracellular vesicles (EV) produced by cultured stem cells as a treatment for injury and degenerative changes of the deep digital flexor tendon (DDFT) and palmar navicular bone fibrocartilage (NBF).

EV, like microscopic membrane-bound packets of beneficial enzymes, growth factors and anti-inflammatory substances, were harvested from cultured mesenchymal stem cells from a donor horse’s bone marrow. The EVs were then added to DDFT and NBF cell cultures grown and maintained in the laboratory. The anti-inflammatory and cartilage protective effects were then evaluated in the cell cultures by measuring the cultured cells’ degradative enzyme activity and products.

The EV demonstrated anti-inflammatory effects, as well as anabolic effects on cartilage that would promote healing, improve the microscopic structure of healed tissues and potentially help return horses to athletic performance. More work is needed before EVs are ready as an off-the-shelf treatment for damaged DDFT and NBF, but this work suggests EVs may be a promising new treatment for navicular disease.

— Quam VG et al. EVJ 2025;57:232-242

Check Ligament Surgery in Warmbloods

Surgeons in Germany reported the outcomes of a series of cases of superficial digital flexor tendinopathy (SDF bowed tendons) treated by cutting the accessory ligament of the SDF (superior or proximal check ligament) in warmblood horses.

The surgeries were performed endoscopically and only the portion of the ligament in the tendon sheath was cut. Following surgery, a full limb bandage was applied for 2 weeks followed by 3 weeks of stall rest, 5 weeks of stall confinement with hand-walking, then an additional 8 weeks of controlled exercise before resuming full training. Sixty-two horses with unilateral or bilateral SDF tendinopathy diagnosed by ultrasound, but no chronic or previous history of SDF injury before this study were enrolled in the study over 3 years.

Following recovery, most (75%) of the horses were sound with about half of these (51%) performing at the same level as before injury. Recurrent SDF injury or persistent lameness was observed in 25% of the horses. Two horses developed serious complications (infected tendon sheaths post-surgery), and one of these had to be euthanized as a result.

Horses with lesions in the proximal third of the SDF had better outcomes than horses with distal lesions, but the size and the type of lesions did not seem to influence the outcomes. Also, the surgery seemed to be of little benefit when performed on the opposite limb as a preventive measure.

— Blatter M et al. EVJ 2024:14437

AI Video Gait Analysis

University of Florida researchers evaluated artificial intelligence (AI) as an aide in the digital evaluation of locomotion among three-day event horses during competition.

The 194 horses in the study were recorded at the trot during the routine pre-event veterinary exam and again following the cross-country phase of the competition. AI allowed the researchers to label 26 anatomical points on 388 videos in just 15 minutes, a task that would have taken several thousand hours of human effort using traditional methods.

Some of the AI-labeled videos had erroneous label placements. However, most of these were easily corrected by visual inspection ensuring the videos only contained complete images in each frame. Following the cross-country phase, significant differences were noted for speed, duty factor (proportion of time during one stride cycle that the hoof spends in contact with the ground) and forelimb swing range compared with the pre-event exams. The differences are all indications of fatigue, which would be expected.

This study was not designed to identify changes in gait due to lameness, but the results suggest using AI to facilitate digital video analysis could be useful to facilitate digital gait analysis on a large scale for such an evaluation in a real-world environment.

— Bucci MP et al. JEVS 2025;146:105344

Trimming Can Move Pressure to the Frog

Veterinarians and farriers in the United Kingdom collaborated on this study to examine the effects of trimming on external hoof measurements, as well as the pressure distribution on the solar surface.

Ten members of the Worshipful Company of Farriers and 50 sound horses were recruited for the study. Most horses were geldings with an average age of about 12 years. Breeds included mostly warmbloods, Thoroughbreds and Irish drafts. Before and after trimming, 18 measurements were taken of each hoof and each horse was walked over a pressure mat to map the pressure distribution of the solar surface.

As one might expect, after trimming the dorsal hoof wall length and heel length, the distance from the apex of the frog to the toe decreased significantly. Dorsal hoof wall and heel angles also increased significantly.

There was no significant change in pressure distribution for most (85%) horses. However, in about 15% of the horses, there was a considerable increase in the pressure that mapped to the frog region. This shift was significantly associated with greater changes following trimming for heel angle, length of the ground surface, distance from the center of pressure to the heel buttress and heel length. About half (58%) of the horses with increased frog pressure following trimming were trimmed by one farrier. The authors suggest this type of increased loading of the frog could result in lameness and should be avoided by adjusting how the hoof is trimmed.

— Seery S et al. EVJ 2025:14463