Originally Printed in the Vail Daily May 21, 2013
Low back pain is one of the most common reasons for lost days from work (and play). A frequent
source of low back pain is dysfunctional sacroiliac joints. The pelvis is made up of three bones, the sacrum, and two ilia. The joint on the front connecting the two ilia is called the pubic symphysis. The joints that connect the ilia to the sacrum at the back are the sacroiliac (SI) joints. They are unusual joints in the body due to their large size and orientation — completely up and down, and rough, uneven surface. This shape and texture allows for a better fit contributing to increased joint stability.
Stability in the pelvis requires more than just good fit and alignment of the joints. Pelvic stability requires form closure, force closure and good motor control. Form closure refers to the stability derived from passive structures, like joint alignment and integrity of the ligaments. Force closure refers to the active components, like muscles and fascia, that help hold the joints together. Many muscles must operate in a coordinated fashion with adequate force to create stability. This is motor control.
SI joints can become dysfunctional and painful for a number of reasons. Trauma can jar the joint, impair its motion or create a slip from its normal alignment. Because the joint space is oriented up and down, forces directed upwards from the ground can create dysfunction. Stepping off a curb unexpectedly with a locked knee or falling directly on one's buttocks (a frequent occurrence in snowboarding), are common mechanisms. Over half of patients with SI dysfunction have a history of some episode of trauma that may have compromised the ligaments, however, relatively minor mechanisms of injury can create problems if joint stability is already compromised. SI problems are common during later stages of pregnancy, mostly due to changes in ligament elasticity. Regardless of how strong or stable the SI joint may be, a sufficient force applied in the right direction can still create problems in even the most robust individuals.
X-ray and MRI are rarely helpful in diagnosis of SI problems. Luckily, a good history and evaluation make diagnosis relatively straightforward. Unfortunately, these same mechanisms can also strain muscles or affect the disc, so getting a good evaluation is important. In uncomplicated cases, dysfunction can result in pain immediately over the joint. It will rarely cause symptoms below the knee, but pain referral into the buttocks, hip and groin is common. Sitting or moving from sitting to standing typically aggravates the pain. Walking may decrease symptoms, however if they are severe walking may also increase pain.
Treatment and prevention of SI dysfunction addresses the components of stability. We can restore form closure by assuring good alignment, appropriate mobility of joints and ligament integrity with mobilization or manipulative techniques. It is possible to enhance force closure by activation and strengthening the muscles of the pelvis and core musculature through exercise. Improving motor control can be accomplished with proper transition from isolated exercise to more functional movements. Addressing only one component may offer some relief, but the best long-term results will address all aspects.