Sacroiliac Joint Dysfunction: Why Pain in the Lower Back and Buttocks May Come From the SI Joint

Pain in the lower back and buttocks is often associated with conditions such as degenerative disc disease, sciatica, or spinal stenosis. However, another possible source of discomfort is the sacroiliac (SI) joint. Sacroiliac joint dysfunction occurs when one or both of the joints connecting the spine to the pelvis become irritated, inflamed, or move abnormally, resulting in pain that can affect daily activities.

Because SI joint pain can resemble other spinal and hip conditions, identifying its source is important for selecting an appropriate treatment plan. Understanding the symptoms, causes, diagnostic process, and available treatments can help patients recognize when the SI joint may be contributing to their lower back and buttock pain.

What Is the Sacroiliac Joint and What Does It Do?

The sacroiliac joints are two joints located on either side of the sacrum, the triangular bone at the bottom of the spine, where it connects with the iliac bones of the pelvis. These joints help transfer the weight of the upper body to the lower extremities while providing stability to the pelvis.

Unlike the hip or shoulder joints, the SI joints have a relatively limited range of motion. Their primary function is to absorb shock and distribute forces between the spine and legs during activities such as walking, standing, lifting, and changing positions.

When these joints become irritated or fail to function properly, the resulting condition is known as sacroiliac joint dysfunction. Even small changes in joint movement or inflammation can contribute to significant discomfort.

What Causes Sacroiliac Joint Dysfunction?

Sacroiliac joint dysfunction can develop for several reasons, including physical stress, changes in joint structure, and underlying degenerative conditions.

Common contributing factors include:

• Degenerative changes: Age-related wear and tear can affect the cartilage and surrounding structures of the SI joint.
• Joint inflammation: Inflammatory conditions, including certain forms of arthritis, can irritate the sacroiliac joints.
• Injury or trauma: Falls, automobile accidents, or direct impacts to the pelvis can damage the joint or surrounding ligaments.
• Pregnancy and childbirth: Hormonal changes can loosen the ligaments supporting the pelvis, while changes in posture and weight distribution place additional stress on the SI joints.
• Muscle imbalances: Weakness or tightness in the muscles surrounding the hips, pelvis, and lower back can affect joint stability.
• Repetitive stress: Activities involving repeated twisting, lifting, or uneven weight distribution may contribute to joint irritation.

In some cases, SI joint dysfunction develops gradually without a single identifiable injury.

What Are the Most Common Symptoms of SI Joint Dysfunction?

The most common symptom of sacroiliac joint dysfunction is pain in the lower back, buttocks, or pelvic region. The discomfort typically occurs on one side, although both SI joints can be affected.

Patients may describe the pain as a deep ache, sharp sensation, or feeling of pressure near the base of the spine. Symptoms may become more noticeable during activities that place stress on the pelvis.

Common symptoms include:

• Pain on one side of the lower back, near the dimples above the buttocks.
• Discomfort that radiates into the buttocks, hip, or upper thigh.
• Increased pain when climbing stairs or walking for extended periods.
• Discomfort when standing on one leg.
• Pain when getting up from a seated position.
• Stiffness after sitting or standing for prolonged periods.
• Increased discomfort when rolling over in bed or changing positions.

Although SI joint dysfunction can cause pain that travels into the leg, symptoms generally do not follow the typical nerve distribution associated with sciatica. Pain extending below the knee is less characteristic and may indicate another underlying condition.

How Is SI Joint Pain Different From Other Types of Lower Back Pain?

Sacroiliac joint pain can be difficult to distinguish from other causes of lower back discomfort because several spinal and musculoskeletal conditions produce overlapping symptoms.

For example, lumbar disc problems can cause pain in the lower back and buttocks, particularly when a damaged disc irritates nearby nerves. Spinal stenosis may produce symptoms that worsen with prolonged standing or walking. Hip conditions can also cause discomfort that extends into the buttocks or groin.

One distinguishing feature of SI joint dysfunction is the location of the pain. Discomfort is frequently concentrated just below the beltline, near one side of the sacrum, and may become worse with movements that transfer weight through the pelvis.

However, symptoms alone cannot confirm the diagnosis. A thorough evaluation is necessary to determine whether the SI joint, lumbar spine, hip, or another structure is responsible.

How Is Sacroiliac Joint Dysfunction Diagnosed?

Diagnosing sacroiliac joint dysfunction typically begins with a review of the patient’s medical history, symptoms, and physical examination.

A pain management specialist may perform several physical tests designed to place stress on the SI joint. These provocative maneuvers involve specific movements or positioning to determine whether they reproduce the patient’s familiar pain.

Common examination techniques include:

• FABER test: Evaluates the hip and SI joint by positioning the leg in a figure-four configuration.
• Thigh thrust test: Applies controlled pressure through the femur to stress the SI joint.
• Compression and distraction tests: Apply pressure to the pelvis to assess whether the maneuvers reproduce SI joint pain.
• Gaenslen’s test: Places stress on the pelvis through controlled positioning of the legs.

Imaging studies, such as X-rays, CT scans, or MRI examinations, may help identify arthritis, inflammation, fractures, or other conditions that could explain the symptoms. However, imaging alone cannot reliably confirm that the SI joint is the source of pain.

A diagnostic SI joint injection may provide additional confirmation. During this procedure, a physician injects a local anesthetic into the joint under imaging guidance. Significant temporary pain relief following the injection can indicate that the SI joint is contributing to the patient’s symptoms.

What Treatment Options Are Available for SI Joint Dysfunction?

Treatment for sacroiliac joint dysfunction depends on the severity of symptoms, the underlying cause, and how much the condition interferes with daily activities. Most treatment plans begin with conservative approaches before considering minimally invasive procedures.

Common treatment options include:

Physical Therapy: Targeted exercises can strengthen the core, gluteal, and pelvic muscles to improve stability and reduce stress on the SI joint. Stretching and movement training may also help restore functional mobility.

Activity Modification: Temporarily limiting activities that aggravate symptoms, such as heavy lifting, repetitive twisting, or prolonged standing, may help reduce irritation.

Medications: Depending on the patient’s medical history, anti-inflammatory medications or other physician-directed treatments may help manage discomfort.

Sacroiliac Joint Injections: Image-guided injections containing a local anesthetic and corticosteroid may help reduce inflammation and provide pain relief. These injections can also help confirm the SI joint as a source of symptoms.

Radiofrequency Ablation (RFA): For certain patients with persistent SI joint-related pain, radiofrequency ablation may be an option. This procedure uses controlled heat to disrupt the sensory nerves carrying pain signals from the joint. It does not repair the joint itself, but it may provide longer-lasting relief than some injection-based treatments.

SI Joint Fusion: In carefully selected patients with persistent, disabling SI joint pain that has not responded to appropriate conservative treatments, minimally invasive SI joint fusion may be considered. The procedure stabilizes the joint by limiting movement between the sacrum and pelvis.

When Should Someone Seek Treatment for SI Joint Pain?

Persistent lower back or buttock pain should be evaluated when it begins interfering with walking, sleeping, exercising, or other everyday activities. Patients should also seek an evaluation when symptoms continue despite conservative treatments or repeatedly return after periods of improvement.

An accurate diagnosis is particularly important because SI joint dysfunction can resemble lumbar spine disorders, hip conditions, and nerve-related pain. Treating the wrong source may delay meaningful improvement.

New bowel or bladder dysfunction, numbness in the groin or saddle region, or progressive leg weakness requires urgent medical evaluation rather than a routine appointment.

Can SI Joint Dysfunction Be Managed Without Surgery?

Many patients with sacroiliac joint dysfunction can manage their symptoms without surgery. Physical therapy, targeted injections, activity modification, and other interventional pain management treatments may help reduce discomfort and improve mobility.

The most effective approach depends on identifying the underlying cause of the pain and selecting treatments that address the affected structures. For patients who continue experiencing significant symptoms, additional diagnostic testing and minimally invasive treatment options may be appropriate.

Recognizing that lower back and buttock pain may originate in the SI joint is an important step toward finding the right treatment. A comprehensive evaluation by a qualified pain management specialist can help identify the source of discomfort and develop an individualized plan to restore function and support a more active lifestyle.