An abnormal gait is adopted either because it eases the pain the horse is enduring or due to chronic changes within the limb that are causing a change in how the limb functions mechanically.
Lameness originating in the foot is by far the most common cause of lameness we see in equine practice. There are a variety of causes including conformation, traumatic injury, and shoeing or trimming issues, and can often be due to a combination of different issues.
The equine foot comprises of a complex alignment of bones, tendons and ligaments, which undergo an intense amount of stress and strain, both at rest and exercise. This means that problems within the foot easily and regularly occur.
Common Symptoms Of Pain In The Foot
- Heat in the foot
- An increased digital pulse – particularly if there is a palpable difference between feet
- Swelling extending above the foot to the pastern, fetlock or carpus.
- Reaction when hoof testers are placed on the sole or the dorsal hoof wall is percussed
The history and severity of the lameness can sometimes give an indication of the likely causes, for example a sub solar abscess often presents as a sudden onset high grade lameness in one foot, whereas navicular syndrome usually manifests as a lower grade lameness and is often bilateral.
Similarly, the horse’s stance can help identify the cause, whether they are happy to weight bear, stand square, or instead choose to point the foot out in front. Horses suffering from laminitis sometimes choose to shift their weight back onto their heels to reduce pressure on the toe area, so carefully examining their resting stance can be really helpful.
Localising the pain to the foot is often straightforward (using clinical examination and nerve blocks), however identifying the specific cause of the problem can be challenging and complicated. Nerve and joint blocks are performed to desensitise specific regions of the horses leg, with an improvement in lameness seen once the area causing the problem has been numbed.
Once this has been performed the next step is often to perform radiographs (x-rays). This can highlight bony changes such as fractures, arthritis, navicular problems, pedal bone rotation and founder, and damage to the bone due to infection (osteomyelitis).
There are many soft tissue structures such as tendons, ligaments and bursae that do not show up. Challenges arise when there are no obvious changes seen on x-ray but the problem has been localised to the foot by nerve blocks. Advanced diagnostic tests such as MRI are then required to visualise soft tissue problems, but cost can be a limiting factor in the availability of these tests.
Common Foot Problems & Injuries In Horses
- Foot abscess
- Solar bruising
- White line disease
- Nail bind
- Navicular syndrome
- Pedal bone fracture
- Pedal osteomyelitis
- Ringbone (arthritis change of the pastern or coffin region)
- Sidebone (ossification of the collateral hoof cartilages)
- Soft tissue injury e.g. the Deep Digital Flexor Tendon as it inserts on the pedal bone