Sacroiliac Joint Function, Diagnosis and Treatment

The sacroiliac joint is stabilized primarily by a network of ligaments, muscular support and proper spinal alignment. The main function of the ligaments that support the SI joint is to limit motion in all planes of movement. The normal sacroiliac joint has a very small amount of normal motion (about 2-4 mm of movement in any direction). For women the SI ligaments are less stiff than men, allowing the increased mobility necessary for the purpose of childbirth. Given their location between the spine and the hip, the sacroiliac joints are responsible for transferring and absorbing the forces that are occurring between the spine and lower extremities. The SI joint is particularly vulnerable to injury because of its location and the crucial balance between stability and mobility that is required for normal sacroiliac function.

Injury to the SI Joint

The largest study to look at how common injury to the SI joint occurs (Bernard and Kirkaldy-Willis) found that 22.5% of patients with reported low back pain had sacroiliac joint pain. The problem is that the SI joints can withstand only 1/20th the compression force (lifting) and half the rotation force (twisting) that the lumbar spine can withstand during these movements. These are the two motions that often strain and injure the sacroiliac joint and thus the mechanism of SI joint injury has often been described as a combination of vertical compression and rapid rotation (i.e. carrying a heavy object and twisting). Additional causes of SI joint pain include arthritis, leg length discrepancy, gait abnormalities, prolonged vigorous exercise, scoliosis and spinal fusion to the sacrum. Lumbar spine surgery has also been reported to trigger sacroiliac joint pain due to SI ligament weakening and postsurgical hypermobility.

Diagnosis of Sacroiliac Joint Pain

One of the most challenging aspects of treating sacroiliac joint pain is the complexity of diagnosis. Literally dozens of physical examination tests have been advocated as diagnostic aids in patients with presumed SI joint pain. One physical finding that has consistently been shown to indicate whether a person has sacroiliac related back pain is specific point tenderness at the SI joint.

Treatment of SI Joint Pain

The treatment of SI joint pain is widely acknowledged to be one of the most challenging problems confronting doctors and physical therapists. Most treatments can be divided into two categories: those directed at correcting the mechanical problem and those aimed at alleviating symptoms.

Conservative treatment of sacroiliac joint pain should ideally address the underlying pathology. Treatments with a physical therapist will typically focus on restoring normal pelvic and core stability (Transversus Abdominis, Multifidus and Pelvic Floor) along with developing good control of general spinal stability with body mechanics retraining, posture correction, etc. Additional exercises will often include general strengthening, stretching and conditioning. Non-surgical stabilization will also be assisted by use of an SI joint stabilization belt that will reduce the movement of an unstable SI joint. In patients with leg length discrepancy, treatment might include the use of shoe inserts to more equally distribute the load exerted on the sacroiliac joints. For SI joint pain resulting from spine misalignment, or if your health care provider feels that your SI joint is hypomobile or too stiff, sacroiliac joint manipulation and/or mobilization will often be recommended. How can two treatments for one joint be so different? Basically, in some cases, SI joint pain is the result of excessive mobility and reducing the mobility of the sacroiliac joint with an SI belt will decrease the pain, on the other hand, if an SI joint is "stiff" or "locked" it may need to be more mobile to function correctly and in this case mobilization or manipulation is the treatment of choice. Furthermore, in many patients a combination of SI joint mobilization and stabilization with an SI belt may be the best treatment.

Sacroiliac Belts and Supports

Pain reduction and stabilization at the SI joint is often best achieved with use of a sacroiliac stabilization belt (SI belt). The SI belt wraps around the hips and pelvic girdle to compress the SI joints and pubic symphysis together, creating the compressive stabilization force that has been lost due to: ligament injury/laxity, core weakness or abnormal SI joint alignment. While many people with sacroiliac related back and pelvic pain experience pain relief using an SI belt, recent biomechanical research has given us insight into why the ACTIVE SI BELT® works better than any other sacroiliac belt that is available!

Additional Treatment Options:

Injections:
Sacroiliac joint injections with corticosteroid and novacaine have been shown to provide good to excellent pain relief lasting from 6 mo to 1 yr. There have been reports of significant SI joint pain relief for patients who have received a series of 3 intraarticular injections with hyaluronic acid. Prolotherapy is another injection that has been advocated as a treatment for SI joint pain. The rationale behind the use of "prolotherapy" is that the hypermobile sacroiliac ligaments, in a patient with SI joint pain, can be strengthened through injecting a drug that promotes ligament stiffness.

Surgery:
In patients with SI joint pain unresponsive to more conservative measures, some have advocated surgery for SI joint stabilization. Based on the existing studies the long-term success rate for SI joint fusion appears to be in the range of 70%. Unfortunately this means that 30% of patients who have sacroiliac joint surgery have increased pain or no change in pain after surgery. As such, surgery is always the last treatment that should be considered for SI joint pain.

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