Sacroiliac pain in horses
What is sacroiliac joint pain?
The sacroiliac joints have long been considered as a source of pain in horses. Pain may be suspected in this area in horses that present with hind limb lameness, performance issues and/or back pain. Reduced hind limb propulsion (push off), poor quality canter, kicking out or bucking, becoming disunited in canter or ‘bunny hopping’ are also signs that have been linked with sacroiliac joint pain. The signs are usually worse when the horse is being ridden, rather than when the horse is lunged.
The anatomy
These days, it is more correct to say that the pain may be coming from the ‘sacroiliac region’, which refers to the sacroiliac joints, the lumbosacral joint, and the ligaments and muscles that surround them. Let’s look at the anatomy…
The sacroiliac joints refer to the ‘articulation’ between the pelvic bone (the ilium) and part of the spine (the sacrum). The job of the sacroiliac joints is to transfer forces from the hindlimbs to the spine to create motion. Therefore, the joints must be strong and stable, and, in most cases, they are. A small amount of movement occurs at the sacroiliac joints, but they are surrounded by strong ligaments and muscles which offer support to the joints.
The lumbosacral joint refers to the ‘articulation’ between the last lumbar vertebrae and the first sacral vertebra. Apart from the neck and tail, it is the area where most of the movement occurs in the horses back. Therefore, the lumbosacral joint can come under strain from new or repetitive training techniques, from poorly fitting tack, or where there is asymmetry, perhaps from hind limb lameness.
The lumbosacral joint, the sacroiliac joints, and the ligaments and muscles that surround them, make up the sacroiliac region.
Causes:
Pain in the sacroiliac region can occur through 2 scenarios. Either through a sudden trauma, like a slip in muddy conditions or a fall when jumping, or through gradual onset where no trauma was involved.
Scenario 1:
Horses who have sustained a sudden injury to the sacroiliac region through trauma, such as subluxation of the sacroiliac joint, or a fracture of the pelvic bone, will be significantly lame and will develop rapid muscle loss on the rump (the gluteal muscles), usually on one side. There may also be signs of swelling or heat in the location of the pain. This is an emergency which requires veterinary assessment.
Scenario 2:
Sacroiliac pain that comes on gradually without any known trauma is more likely to be due to degenerative changes of the joints and surrounding ligaments, and tension of the surrounding muscles. This could be because of uneven weight transfer through the joints due to hind limb lameness or asymmetry, poorly fitting tack, or new or repetitive training techniques. There may be some visible asymmetry of the pelvis when viewed from behind, and some loss of gluteal muscle bulk over the rump, but it occurs slowly, over time. The bones of the sacrum and ilium can start to appear more prominent, often known as a ‘jumpers bump’ or ‘hunters bump’.
Diagnosis:
Diagnosing pain in the sacroiliac region can be quite complex and should involve ruling out any other causes of hind limb lameness first. It is not practical to X-ray the sacroiliac region as the bones are very deep and this make the images difficult to interpret. Ultrasound scanning of the sacroiliac joints and ligaments can be performed either through the gluteal muscles or through the rectum. Only a small amount of the sacroiliac joints can be visualised this way, but it is the part of the joint which often becomes problematic. Some veterinary practices may use bone scanning (scintigraphy), which can be useful, but can lead to false positive and false negatives, due to the depth of the tissues and the nature of the exam. Therefore, the results need to be interpreted along with the whole clinical presentation.
Another way to test whether the sacroiliac region is the source of pain is by delivering an anaesthetic block (an injection) into the local area. This is something that can be performed by your vet. There should be a significant improvement in the horse’s movement or performance shortly after the block has taken effect, for this diagnostic test to be positive and indicate pain in the sacroiliac joint region. If the block is combined with a steroid medication, this can help to reduce any inflammation in the area and act as pain relief. Following an injection, a gradual return to exercise is usually recommended and you should be guided by your vet. In most cases, box rest is not recommended as it can lead to stiffness and further muscle wasting.
Physiotherapy:
Physiotherapy is an essential component in the treatment of pain in the sacroiliac region and may be used on its own in milder cases or following an injection as part of a veterinary treatment plan. Physiotherapy helps to relieve the pain and tension in the surrounding muscular, which occurs due to the underlying joint pain. This helps the muscles to relax and allow them to work more effectively, helping to build strength and stability in the sacroiliac region.
I use a combination of electrotherapy, manual therapy (like massage and joint mobilisation), stretches and rehabilitation exercises to restore normal movement of the spine and hindlimbs, leading to increased strength and control around the pelvic area. This leads to quicker recovery times, better performance, and less chance of the sacroiliac pain recurring.
If you have noticed changes in your horse’s performance, or if you suspect your horse may have sacroiliac pain or back pain, please contact either myself or your vet for advice on assessment and treatment. Thanks for reading!
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