What are the causes of sacroiliac joint dysfunction?
As with most other joints in the body, the SI joints have a cartilage layer covering the bone. The cartilage allows for some movement and acts as a shock absorber between th
e bones. When this cartilage is damaged or worn away, the bones begin to rub on each other, and degenerative arthritis (osteoarthritis) occurs. This is the most common cause of SI joint dysfunction. Degenerative arthritis occurs commonly in the SI joints, just like other weight-bearing joints of the body.
Any condition that alters the normal walking pattern places increased stress on the SI joints. This could include a leg length discrepancy (one leg longer than the other), or pain in the hip, knee, ankle, or foot. Patients with severe pain in the lower extremity often develop problems with either the lower back (lumbar spine) or SI joints. Usually, if the underlying problem is treated, the associated lumbar spine or SI joint dysfunction will also improve.Another common cause of SI joint dysfunction is pregnancy. During pregnancy, hormones are released in the woman’s body that allows ligaments to relax. This prepares the body for childbirth. Relaxation of the ligaments holding the SI joints together allows for increased motion in the joints and can lead to increased stresses and abnormal wear. The additional weight and walking pattern (altered gait) associated with pregnancy also places additional stress on the SI joints.
There are many disorders that affect the joints of the body that can also cause inflammation in the SI joints. These include gout, rheumatoid arthritis, psoriatic arthritis, reactive arthritis, and ankylosing spondylitis. These are all various forms of arthritis that can affect all joints. Ankylosing spondylitis is an inflammatory arthritis that always affects the SI joints. It can lead to stiffness and severe pain in the SI joints, due to inflammation in the sacroiliac joints (sacroiliitis). As the disease process continues, the SI joints can fuse together and have no range of motion. Once this occurs, there is no further pain associated with the SI joints. Rarely, bacterial infection can involve the sacroiliac joints.