Horses are affected by lameness in many different ways. The degree of lameness can range from a subtle reduction in performance to a complete loss of mobility. Lameness can be caused by pain coming from wounds to skin, connective tissue bruising, muscle pain, arthritis, inflammation, tendon and ligament injury, or injuries to bone. Working with an equine veterinarian who has experience with equine lameness can help horse owners determine the cause of their horse′s pain.
The lameness exam is a thorough and methodical exam which is the cornerstone of lameness diagnosis. This detailed veterinary procedure includes the following steps:
1. Obtain a Thorough History: The doctor or technician will inquire about the horse′s age, breed, what the horse is used for, the date that lameness was first noticed, and how the injury occurred, if known.
2. Standing Examination: The horse will be observed at a distance to evaluate conformation and also examined up close to palpate specific structures and identify any swelling, heat, pain, etc.
3. Hoof Tester Examination: Hoof testers allow the doctor to put pressure on specific regions of the foot in search of a pain response. This helps determine whether or not the lameness is in the hoof and pinpoint the location.
4. Examination in Motion: This portion of the exam is usually performed on firm, even footing. The horse′s movement is usually evaluated at the walk and trot in straight lines and circles in both directions.
5. Flexion Tests: Flexing joints or regions of the limbs for a specified time also aids the doctor in determining the source and degree of lameness. The limb is held in different flexed positions that put stress on certain joints. Then the horse is trotted off and the lameness is evaluated. As with many parts of the exam, flexion tests are interpreted in consideration of what is normal for that specific horse.
6. Nerve Blocks: In order to methodically numb portions of the limb, a temporary “block” is produced by injecting a local anesthetic around specific nerves, joints or other structures. The horse is assessed at the trot before administering the block. Then the area in question is numbed, and the horse is asked to trot off again. If there is no improvement, the process is continued by progressing up the limb until the lameness is lessened or abolished. This identifies the specific region of the pain.
7. Diagnostic Imaging: Once the source of pain has been located, it is often helpful to visualize the structures in that area with diagnostic imaging. This may include taking x-rays of bone structures or an ultrasound of soft tissues.
The complete lameness exam synthesizes the results of these parts to reach a conclusion about what kind of treatment may be helpful for the horse.