The sacrum is the triangular bone at the very bottom of the spine. It is actually five vertebrae that have been fused to make one large bone. On either side of the sacrum is a joint where it connects the spine to the hipbones, also known as the iliac bones. This joint is known as the Sacroiliac joint or the SI joint. This joint is held together by several strong ligaments. While there is not a lot of motion at this joint, there is some motion. This joint bears a lot of weight, as it is the skeletal connection between the upper body and the lower body. So a lot of stress is placed through these joints. This stress can lead to wear and tear on the joints known as arthritis. SI joint dysfunction is also known as inflammation of the SI joints or Sacroiliac joint syndrome.
The causes of SI joint dysfunction can be degenerative arthritis or a sprain of the joint. Also pregnancy causes altered gait mechanics and hormonal changes that make the ligaments more lax. This leads to increased motion in the SI joint and causes pain. SI joint dysfunctions can begin as a result of a fall or another injury that alters the gait pattern. If a person has a knee, hip, or ankle surgery or injury, they may develop inflammation of the SI joints that presents as low back pain.
Symptoms present as low back pain or hip pain. The patient may have pain in the groin or thighs. Sometimes the patient will have sciatica type pain. SI joint pain is usually worse with standing and walking, unlike with other forms of low back pain. SI joint dysfunction is often diagnosed based on history and symptoms. Other causes of low back pain should be ruled out. Your physician or physical therapist may perform specific tests for the SI joint to assess movement and dysfunction. Physical exam of the SI joints will assist in making the diagnosis.
Treatment consists of reducing inflammation, restoring motion and proper mechanics and improving stability of the joint. A physician, to reduce pain and inflammation, may use oral medication or injections. A physical therapist will help to restore proper motion and improve stability of the segment. Physical therapy for SI joint dysfunction typically involves the use of modalities to reduce inflammation and decrease pain. Manual therapy is used to restore proper motion and alignment of the joint. Therapeutic exercise is then used to improve stability, flexibility, strength, and range of motion. The patient is then instructed in home exercises and self-management techniques to avoid further injury and allow full return to function.