Sacroiliac joint dysfunction (SIJD) is a musculoskeletal disorder and common cause of low back pain that occurs due to inflammation of the sacroiliac joints (SIJs or SI joints). Inflammation at these joints can result from injury, illness, or several chronic conditions — including spinal muscular atrophy (SMA). SIJD causes a range of symptoms that can be mild or debilitating. Accurate diagnosis of SI joint dysfunction can be difficult, but, ultimately, it is a very treatable condition.

What Are SIJs?

SIJs connect the spine to the hip bones. The sacrum is the lowest part of the spine, beneath the lumbar spine. Each side of the sacrum connects to the ilium, the upper part of the hip bone, forming joints that support the torso at the hips. Together, the sacrum and hips form the pelvis. The SIJs do not move much. They are designed to act as “shock absorbers” to transfer weight from the upper body to the pelvis. Like other joints, the sacrum and ilium are connected by ligaments, but the ligaments do not allow the sacroiliac joint to move the way most other joints do.

What Is Sacroiliac Joint Dysfunction?

SIJD occurs when there is pain and altered mobility of the SIJs. SIJD can cause or be caused by sacroiliitis, inflammation of the sacroiliac joint. SIJD can have several different causes that can involve either too much movement of the SIJ (hypermobility) or too little (hypomobility). Some causes of SIJD include:

• Injuries to the pelvis from trauma or overtraining
• Inflammation due to degenerative joint disease (osteoarthritis) or other types of arthritis, such as ankylosing spondylitis
• Conditions that cause muscle weakness or instability, such as SMA
• Other conditions that cause lower body instability, abnormal gait, and abnormal movement of the pelvis (such as a difference in leg length)

In pregnancy, pelvic pain can be caused by SIJD due to laxity in pelvic ligaments.

SIJD Symptoms

Symptoms of SI joint dysfunction can be the same as other conditions that cause pain in the lower back, hips, buttocks, and thighs. SIJD can cause acute and chronic pain. Sacroiliac joint pain is the primary symptom of SIJD, but that pain often extends beyond the SI joint. Dull or aching pain in the lower back and along the hip bone (iliac crest) is typical in SIJD. Pain can involve the upper to mid buttocks or extend around the side of the upper hips to the upper thigh and groin. Pain can also be sharp or stabbing and can extend down the leg above the knee. The range of motion of the back and hip joints may be limited by pain and stiffness.

Pain and other symptoms of SIJD can mimic sciatica, a herniated disc, radiculopathy, and other causes of back pain. Pain may affect only one side of both sides of the SIJ. Pain is typically worse with walking, standing, bending over, or sitting for a long time. Pain is usually relieved by lying down, especially lying on the side of the body opposite to the painful side. Joint stiffness and hypomobility may occur with SIJD. Hypermobility of the SIJ can also occur, leading to lower body instability.

SIJD Diagnosis

SIJD shares many symptoms with other causes of lower back and hip pain, so other causes must be ruled out to diagnose SIJD. A physical exam for SIJ pain involves testing muscle strength and range of motion in addition to localizing the source of pain. Several tests are designed to identify SI joint pain. These involve putting pressure on the sacrum, hip, upper thigh, and hip joint while lying down, standing, or with the legs in various positions. If three or more of these tests reproduce pain, it can indicate SIJD.

The source of pain must include the SIJ and not have another cause (such as a herniated disc). Diagnosis of sacroiliac joint dysfunction cannot be performed using imaging studies, such as X-rays because there are no clear signs of SIJD that can be identified. The absence of other causes of pain can support a diagnosis of SIJD. Another way to diagnose SIJD that is considered the most reliable is to inject an anesthetic into the joint space — if the pain improves, SIJD may likely be the cause.

SIJD Treatments

Treatments for SIJD are the same as for many other causes of lower back pain. The primary goal of treatment is pain relief. Treatment options include:

• Ice and heat therapy
• Pain medication, such as nonsteroidal anti-inflammatory drugs (NSAIDs) or opiates for severe, acute pain
• Joint manipulation/manual therapy (by a chiropractor or osteopathic doctor)
• Muscle relaxants
• Acupuncture and acupressure
• Sacroiliac joint injections (local anesthetic plus a corticosteroid)
• Physical therapy to strengthen core muscles
• Braces to support the pelvis
• Orthotics to correct gait
• Radiofrequency nerve ablation
• Surgery (joint fusion)

SIJD Outlook

Depending on the cause of SIJD, symptoms may be short-term or longer-lasting. Addressing acute causes of SIJD, such as an injury or acute inflammation, can help resolve symptoms. Chronic SIJD can be treated using a combination of therapies that correct underlying causes. Strengthening muscles that stabilize the spine and pelvis is one of the best ways to treat and prevent SIJD, but this is not always possible in conditions such as SMA.

When other treatments fail, surgery to fuse the SI joints is an option. However, surgery doesn’t always achieve the desired results, and postoperative recovery should also be seriously considered. Overall, although SIJD can be a painful and debilitating condition, there are many effective treatments available to relieve symptoms, restore function, and improve quality of life.

Using a brace that supports the spine and torso (thoraco-lumbo-sacral orthosis) may also help alleviate symptoms by stabilizing the spine. The use of a pelvic brace or belt can help symptoms caused by hypermobility. Orthotics or knee and ankle braces that correct gait problems can also prevent instability that causes chronic SI joint dysfunction.

Talk With Others Who Understand

On mySMAteam, the social network for people with SMA, more than 1,300 members come together to ask questions, give advice, and share their stories with others who understand life with spinal muscular atrophy.

Are you or someone you care for living with SIJD? Share your experience in the comments below, or start a conversation by posting on your Activities page.