The current "gold standard" for diagnosis of sacroiliac joint dysfunction emanating within the joint is sacroiliac joint injection confirmed under fluoroscopy or CT-guidance using a local anesthetic solution. The diagnosis is confirmed when the patient reports a significant change in relief from pain and the diagnostic injection is performed on 2 separate visits. Published studies have used at least a 75 percent change in relief of pain before a response is considered positive and the sacroiliac joint deemed the source of pain.    However, several other injection studies have compared intra-articular with extra-articular injection, and indicate that the ligament injection behind the joint is oftentimes superior to injection in the joint and seems to be a very underutilized diagnostic tool.  
We would like to make several recommendations pursuant to the treatment your horse just received for sacroiliac joint pain (arthritis). A combination of both short- and long-acting steroid as well as a synthetic hyaluronan were infused into both left and right sacroiliac joints. The joints were treated through a common injection portal. An analgesic (pain killer) was administered along with the sedative to reduce discomfort during the procedure, and 2 grams phenylbutazone was administered intravenously to reduce discomfort over the next 12-24 hours. No more medication for discomfort is required.
Joint pain can be caused by injury affecting any of the ligaments, bursae, or tendons surrounding the joint. Injury can also affect the ligaments, cartilage, and bones within the joint. Pain is also a feature of joint inflammation ( arthritis , such as rheumatoid arthritis and osteoarthritis ) and infection, and extremely rarely it can be a cause of cancer of the joint. Pain within the joint is a common cause of shoulder pain , ankle pain , and knee pain . Joint pain is also referred to as arthralgia . The sexually transmitted diseases ( STDs ) chlamydia and gonorrhea can lead to joint pain.