Sacroiliac (SI) Joint Pain: Symptoms, Diagnosis, and Treatment Options

Lower back pain is one of the most common reasons people seek medical care, but not all back pain comes from the spine itself. In many cases, the source of discomfort may actually be the sacroiliac (SI) joint. Because SI joint pain can mimic conditions such as sciatica, herniated discs, or hip problems, it is often overlooked or misdiagnosed.

Understanding the symptoms, causes, and treatment options for SI joint dysfunction can help patients find the right care and achieve lasting relief.

What Is the Sacroiliac (SI) Joint?

The sacroiliac joints are located where the sacrum (the triangular bone at the base of the spine) connects to the iliac bones of the pelvis. There are two SI joints — one on each side of the lower back.

These joints play an important role in:

• Supporting body weight
• Absorbing shock during movement
• Stabilizing the pelvis and spine
• Transferring force between the upper body and legs

Although the SI joints move only slightly, inflammation or dysfunction in this area can cause significant pain and mobility problems.

Common Symptoms of SI Joint Pain

SI joint pain can vary from mild discomfort to severe, debilitating pain. Symptoms are often felt on one side of the lower back but may affect both sides in some cases.

Common symptoms include:

• Pain in the lower back or buttocks
• Hip or groin pain
• Pain that radiates down the leg
• Discomfort when standing up from a seated position
• Increased pain while climbing stairs or walking uphill
• Stiffness in the pelvis or lower back
• Difficulty sitting or standing for long periods

Many patients describe SI joint pain as a deep ache or sharp stabbing sensation near the dimples of the lower back.

What Causes SI Joint Dysfunction?

Several conditions and injuries can contribute to SI joint pain, including:

Arthritis

Osteoarthritis can wear down the cartilage within the SI joint over time, leading to inflammation and pain.

Pregnancy

Hormonal changes and increased stress on the pelvis during pregnancy can loosen the SI joints, sometimes causing instability and discomfort.

Injury or Trauma

Falls, car accidents, or sports injuries may damage the SI joint or surrounding ligaments.

Repetitive Stress

Activities involving uneven weight distribution or repetitive twisting motions can strain the joint.

Leg Length Differences

Even small differences in leg length can alter walking mechanics and place additional stress on the SI joints.

Previous Spine Surgery

Patients who have undergone lumbar fusion surgery may develop SI joint pain due to altered spinal biomechanics.

How SI Joint Pain Is Diagnosed

Diagnosing SI joint dysfunction can be challenging because its symptoms overlap with many other spine and hip conditions.

A thorough evaluation often includes:

Medical History and Physical Examination

A physician will review symptoms, movement limitations, and activities that worsen pain. Specific physical maneuvers may help reproduce SI joint discomfort.

Imaging Studies

X-rays, CT scans, or MRIs may be used to rule out other conditions such as disc herniation, fractures, or hip disorders.

Diagnostic SI Joint Injection

One of the most reliable ways to confirm SI joint pain is through a diagnostic injection. Using imaging guidance, a physician injects a local anesthetic into the SI joint. Significant temporary pain relief suggests the SI joint is the primary pain source.

Non-Surgical Treatment Options

Many patients experience significant improvement with conservative treatments.

Physical Therapy

A targeted physical therapy program can strengthen the muscles supporting the pelvis, improve flexibility, and reduce joint stress.

Anti-Inflammatory Medications

Nonsteroidal anti-inflammatory drugs (NSAIDs) may help reduce inflammation and pain.

Activity Modification

Avoiding activities that aggravate symptoms can allow the joint to heal and reduce irritation.

SI Joint Belt

Support belts worn around the pelvis may help stabilize the SI joint, especially during pregnancy or prolonged activity.

Chiropractic Care or Manual Therapy

Some patients benefit from carefully guided joint mobilization techniques that improve alignment and movement.

Minimally Invasive Interventional Treatments

When conservative treatments fail to provide adequate relief, interventional pain management procedures may be considered.

Corticosteroid Injections

Image-guided SI joint injections deliver anti-inflammatory medication directly into the affected joint to reduce swelling and pain.

Radiofrequency Ablation (RFA)

Radiofrequency ablation uses heat generated by radio waves to interrupt pain signals from the nerves surrounding the SI joint. Relief may last several months or longer in appropriate candidates.

Regenerative Medicine Therapies

Some physicians may recommend regenerative therapies such as platelet-rich plasma (PRP) injections to support tissue healing, although research is still evolving.

When SI Joint Fusion May Be Recommended

For patients with chronic, severe SI joint dysfunction that does not improve with non-surgical care, minimally invasive SI joint fusion may be considered.

This procedure stabilizes the joint using small implants to reduce abnormal motion and pain. Advances in minimally invasive techniques have improved recovery times and reduced surgical disruption compared to traditional open surgery.

When to Seek Medical Attention

Patients should seek evaluation if they experience:

• Persistent lower back or buttock pain
• Pain that interferes with daily activities
• Difficulty walking or standing
• Symptoms that worsen over time
• Pain that does not improve with rest or conservative care

Early diagnosis can help prevent prolonged discomfort and guide more effective treatment.

Final Thoughts

SI joint pain is a common but frequently misunderstood cause of lower back and pelvic discomfort. Because its symptoms often resemble other spine or hip conditions, obtaining an accurate diagnosis is essential.

Fortunately, a wide range of treatments — from physical therapy and injections to minimally invasive procedures — can help patients manage symptoms and improve quality of life. With the right treatment plan, many individuals are able to return to normal activities with significantly less pain.