Sacroiliac Joint Abnormalities in Horses

Acute and severe strain of the sacroiliac ligaments in horses is associated with a history of injury and severe pain in the pelvic or sacroiliac region, often with marked hindlimb lameness. Subacute or chronic sacroiliac strain and osteoarthrosis of the sacroiliac joint cause typical back soreness. There is often a history of poor performance, with an intermittent, often shifting, hindlimb lameness that might be associated with some restriction in hindlimb action and dragging of the hindlimb toes.

Sacroiliac pain and lesions are challenging to definitively diagnose. Suggestive physical examination findings, exclusion of other lameness causes, and scintigraphic uptake in the sacroiliac region are usually required to confidently diagnose sacroiliac pain in horses. Improvement in gait after local anesthetic is infiltrated into the sacroiliac joint might confirm diagnosis; however, infiltration risks sciatic nerve paralysis.

Ultrasonography can be informative in cases of sacroiliac disease, but some horses without sacroiliac pain will also have abnormal ultrasonographic findings in this area. The ventral aspect of the sacroiliac joint in horses can be ultrasonographically assessed using a rectal probe.

Abnormal ultrasonographic findings at the ventral aspect of the sacroiliac joint in clinical cases include bone remodeling of the sacrum and/or ilium, narrowing of the joint space, remodeling or formation of periarticular osteophytes of the caudal border of the articular surface of the sacrum and caudal articular margin of the ilium, periarticular bone fragmentation, and ventral sacroiliac ligament desmopathy and enthesopathy.

The treatment and management of sacroiliac disease in horses is usually supportive and nonspecific. Therapies include periarticular injection of steroids, shock wave therapy, pulsed electromagnetic therapy, and rehabilitation using progressive warm-up at a slow canter and exercises that develop the gluteal muscles.