Can You Dislocate Your SI Joint? And What to Know

The sacroiliac (SI) joint, located where the sacrum connects with the ilium, primarily provides stability and shock absorption with very limited movement. While a true dislocation is uncommon, this joint can experience significant pain and dysfunction.

Understanding the Sacroiliac Joint

The sacroiliac joint (SI joint) connects the sacrum and the two iliac bones of the pelvis. There are two SI joints, one on each side, linking the spine and lower extremities. Its irregular, interlocking surfaces and strong ligaments contribute to its robust stability.

The main function of the SI joint is to transfer upper body weight to the lower limbs and act as a shock absorber for forces traveling up from the legs. Its movement is quite restricted, typically only 2-3 millimeters. A complete dislocation, where bones fully separate, is rare and usually occurs due to high-energy trauma, such as severe accidents. However, injuries like incomplete dislocations can still happen.

What is SI Joint Dysfunction?

Sacroiliac joint dysfunction, a more common issue than full dislocation, involves either too much (hypermobility) or too little (hypomobility or fixation) movement within the joint. When the joint moves excessively or is overly restricted, it can lead to pain. Factors contributing to SI joint dysfunction include trauma, such as falls, car accidents, or repetitive microtrauma.

Repetitive stress from poor body mechanics or improper lifting can also strain the joint. Pregnancy is a common cause, as hormonal changes increase ligamentous laxity in the pelvis, leading to hypermobility. Other factors include degenerative changes like arthritis, leg length discrepancies, and previous lower back surgeries, which can alter pelvic biomechanics.

Symptoms of SI joint dysfunction include lower back pain, typically on one side, but it can also spread to the buttock, hip, groin, or thigh. This pain is described as dull, aching, or sometimes sharp and stabbing. It may mimic sciatica, radiating down the leg, though it usually remains above the knee. Activities that worsen the pain include prolonged standing or walking, climbing stairs, getting up from a seated position, and turning over in bed or sleeping on the affected side. Individuals may also experience stiffness, particularly in the morning, numbness, tingling, or a feeling of leg instability.

Identifying and Addressing SI Joint Issues

Diagnosing SI joint issues begins with a thorough physical examination. Healthcare providers perform specific provocative tests to reproduce the pain, helping to pinpoint the SI joint as the source. Imaging techniques like X-rays or MRI scans rule out other conditions that can cause similar symptoms, such as disc herniation or hip problems. A diagnostic injection of a numbing medication directly into the SI joint can also confirm the diagnosis; if the pain significantly decreases after the injection, it suggests the SI joint is the source of discomfort.

Conservative treatment is usually the first approach for managing SI joint dysfunction. Physical therapy is a primary component, focusing on exercises to strengthen the muscles that stabilize the pelvic girdle, including core, gluteal, hamstring, and back muscles. These programs also incorporate stretching to improve flexibility and restore proper joint movement. Pain management strategies include over-the-counter or prescription nonsteroidal anti-inflammatory drugs (NSAIDs) and muscle relaxants. Therapeutic injections, such as corticosteroids, can be administered into the joint to reduce inflammation and provide pain relief. A pelvic belt may be recommended, particularly for individuals experiencing hypermobility, like postpartum patients, to provide external support. When conservative treatments do not provide adequate relief, surgical options may be considered as a last resort. Sacroiliac joint fusion stabilizes the joint, often performed using minimally invasive techniques to fuse the sacrum to the ilium.