Sacroiliac joint pain can be very severe and easily confused with lumbar disc pain based on the typical referral pattern of pain, often down the posterior thigh. It is also the most common culprit in low back pain in pregnancy. Pain is often worse with a sit to stand motion, walking or stairs and generally better with rest. The SI joint needs to be able to provide optimal stability for the pelvis while also providing an essential amount of motion. SI joint pain can be caused by a variety of muscle imbalances in the lumbopelvic region, or even in the lower extremity. For example in many patients, the larger gluteal muscles (which cross the SI joint at nearly a 90 degree angle) provide an insufficient amount of stability for the joint, while the smaller hip external rotator muscles (which cross the joint line, below the SI) are over active. This can cause compression on the lower SI preventing optimal movement.
Other patients, possibly a runner, could have insufficient movement and thus force dampening occurring at the foot and ankle which causes the force to move up the leg and may cause compression at the SI joint, restricting its movement. SI joint dysfunction requires a multifaceted treatment approach that starts with an accurate diagnosis including appropriate diagnostic imaging with a goal of not just figuring out the “what” but also the “why.” Treatment would typically include a functional rehabilitation program, appropriate soft tissue treatment with other forms of myofacial release, joint manipulation or mobilization and patient education.