One of the most common causes of poor performance in horses is pain caused by musculoskeletal disorders. “Is my horse lame?” “Where is the pain coming from?” are frequent questions that owners ask themselves. Here you can find information about evaluating the lame horse – lameness causes, signs and treatment.
Lameness is defined as any abnormality in the gait and stance of a horse, caused by different injuries and having different origins. The level of severity is graded on a scale from 1-10. A slightly lame horse would be graded 1-2/10ths lame and a not weight bearing horse would be graded 10/10ths lame.
Lameness is categorised as acute or chronic. Acute lameness means it appeared recently & suddenly, and chronic describes an ongoing lameness that started a while ago. Lameness can be persistent or intermittent (it comes and goes). If the lameness worsens with exercise or time it is called progressive and static if it stays the same.
What causes the lameness?
- Traumatic injuries (accidents, stone bruises, overtraining, overloading)
- Degenerative diseases (arthritis)
- Genetic diseases (limb deformity)
- Neurologic diseases (nerve damage)
- Metabolic diseases (Cushing disease, Equine Metabolic Syndrome)
- Environment (stones, muddy fields)
Where is the pain coming from?
Neck? Back? Foot? Limbs?
Some of the most common causes of lameness in horses are traumatic injuries (tendon tears, splint bone fractures), foot disorders (laminitis, hoof abscess), and degenerative joint disease (arthritis, osteochondritis dissecans).
To achieve a successful lameness investigation, following steps have to be followed:
The first step of a lameness investigation is to observe the behaviour of the horse.
- History of the lameness (discussion with the owner about the beginning and duration of lameness, training programme, previous injuries and previous treatment)
- Examination of the horse at rest (conformation, feet balance, stance, weight bearing, presence of wounds)
- Evaluation of the horse at walk, trot and canter on both reins, on soft and hard surface and sometimes under the saddle.
- After identifying which limb is affected, palpation of muscles, joints and bones is the next step in order to find the painful anatomical area (presence of heat, swelling, pain). Application of hoof testers to check the presence of pain in the foot.
- Joint flexion tests: the vet holds each joint in a flexed position for 30-60 seconds before the horse is trotting away. If the level of discomfort increases, the pain is likely to originate in the structures within the flexed joint.
If the clinical assessment cannot offer enough information about the lameness origin and mechanism, the vet will perform some diagnostic tests:
- Nerve and joint blocks – the vet will inject local anaesthetic in order to desensitise each region of the limb, one region at a time, starting with the lowest point until the lameness disappears or improves. If the lameness has diminished, the source of pain likely resided in the blocked anatomical area. Often horses can be lame in more than one limb, so nerve blocking one may reveal another lameness.
Once the pain is localised, radiographs can be taken to find the cause of the pain.
- Radiography provides information about bone structures and joints and very little information about soft tissues like tendons and ligaments
- Ultrasound provides information about soft tissues like tendons, ligaments and blood vessels, fluid presence and bone shape irregularity
- CT, MRI, Scintigraphy are advanced diagnostic techniques often used to diagnose pathologies, difficult to visualise with radiography or ultrasound.
- Joint fluid sample of distended joints can be examined for infection or inflammation
Treatment and prognosis
These are very different depending on the cause of lameness, damage extent, use of the horse, age of the horse, financial situation.
In case of low-grade lameness, box rest, controlled hand walking, physiotherapy, anti-inflammatory drugs like phenylbutazone (Bute) might be sufficient.
Remedial and corrective farriery are essential in case of poor feet balance, laminitis, tendon injuries or limb deformities.
Nutritional balance and diet are very important when treating lameness in overweight horses.
In many other situations joint injections might be necessary. Corticosteroids, Irap (Interleukin-1 Receptor Antagonist Protein), platelet rich plasma, stem cells can be injected depending on pathology. Surgeries (arthroscopy, fracture repair) are sometimes the only way to treat severe injuries.
Lameness investigation is often a very long and sometimes frustrating process, that can reveal new sources of pain. If you identify even a minor lameness, try to minimise the risk of injury and contact your vet for further advice.