Sacroiliac (SI) joint arthritis is a chronic degenerative condition of the joint that connects the pelvis with the lower back. SI joint arthritis usually causes pain, loss of function, and inflammation of the hips, pelvic region, and lower back.

Arthritis is a condition that affects the joints, causing pain, inflammation, and stiffness. It can also affect the SI joint.

Treatment for SI joint arthritis may include medicines, physical therapy, surgery, and lifestyle modifications.

This article explores the types, symptoms, causes, and treatment options for SI joint arthritis.

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According to a 2022 article, the SI joint is where the sacrum and ilium connect in the lower back.

The sacrum is a large, triangular-shaped bone located at the base of the spine, just above the tailbone. The ileum is the most significant and uppermost portion of the hip bone. The two bones interlock to reduce the chances of dislocation and allow little flexibility.

There are two SI joints on each side of the body connecting the spine to the pelvis.

The SI joint plays a significant role in the body’s mobility, stability, and resistance against shear forces.

As the largest axial joints in the body, both SI joints transfer the body’s weight and evenly distribute it from the lumbar spine to the lower extremities.

The following types of arthritis can affect the SI joint, resulting in SI arthritis. This includes:

Osteoarthritis (OA)

OA is a chronic degenerative joint disorder, causing inflammation and changes in bone and joint tissues.

It can affect the entire SI joint, including the joint lining and cartilage, leading to joint injury due to the formation of bone spurs.

Rheumatoid arthritis (RA)

RA occurs when the body’s immune system attacks healthy tissues.

Although RA affects multiple joints in the hands, wrists, and knees, it can also affect the SI joint. RA of the SI joint may reduce movement and increase joint degeneration in people with the condition.

Systemic lupus erythematosus (SLE)

SLE is a degenerative autoimmune disease in which the immune system produces antibodies against the body. It is a multisystem disorder.

This means it can attack different healthy cells, tissues, and organs in the body, including the SI joint.

A 2020 study suggests that people with SLE have a greater chance of having arthritis in their SI joint than others.

Ankylosing spondylitis (AS)

AS is a form of arthritis that causes inflammation in the joints and ligaments of the spine.

Inflammation due to AS can spread from the spine to the SI joint, causing pain and loss of spine movement. A person with this condition may have difficulty bending and climbing the stairs.

Research suggests that it is more common in males, and 80% of those who develop the condition are under the age of 30.

Psoriatic arthritis (PsA)

PsA is a form of arthritis that affects 1 in 3 people with psoriasis — a skin condition that causes itchy, scaly patches in the knees, elbows, and scalp.

Research from 2020 suggests that while SI joint arthritis is prevalent among people with PsA, it can be asymptomatic.

Gout and pseudogout

Gout occurs when needle-like crystals from monosodium urate form in the joints. Pseudogout is due to crystals of calcium pyrophosphate (CPP). A buildup of uric acid crystals in the joint’s soft tissues can cause pain, swelling, and stiffness.

According to a European Journal of Rheumatology report, while gout primarily affects the big toe, it can also affect the SI joint.

Reactive arthritis

Reactive arthritis occurs when sexually transmitted or pathogenic bacteria spread to different parts of the body and invade healthy joints.

The National Organization for Rare Diseases (NORD) notes that the sacroiliac joints and large joints of the lower limbs are most often affected.

Some common symptoms of SI joint arthritis include the following:

  • stiffness or loss of flexibility
  • swelling
  • limited range of movement
  • pain

People may feel pain ranging from mild to severe in the hips, lower back, buttocks, groin, and one or both legs.

A person may experience any of these symptoms after:

  • sitting, standing, or walking for long hours
  • bending
  • stretching
  • running
  • climbing the stairs
  • placing too much weight on one leg or side of the body

According to a 2022 study, 25% of low back pain will arise from the sacroiliac joint.

If a person has lower back pain from SI joint arthritis, the doctor can recommend the following home remedies for temporary relief.

This includes:

  • applying an ice pack or hot compress to the painful area
  • applying pain-relief cream
  • massage
  • physical therapy and exercise

The doctor will assess the cause and intensity of a person’s symptoms to determine the best treatment. This may include:

Medication

The doctor can prescribe over-the-counter (OTC) pain relief medications like Tylenol or ibuprofen. They may also prescribe strong painkillers such as corticosteroid injections if a person’s pain is severe.

Other medical therapies may include:

  • muscle relaxers
  • radiofrequency denervation, which uses radiofrequency to destroy pain-causing nerve tissues
  • tumor necrosis factor (TNF) inhibitors to treat SI joint arthritis due to AS

Surgery

The doctor will recommend surgery as a last option when other treatments, such as medications and self-care remedies, are ineffective. It may involve a joint fusion surgery where the doctor fuses two bones with a metal plate.

Other factors may cause SI joint pain, including:

A person should contact a doctor if they are experiencing pain, inflammation, or loss of movement in the hip or lower back region.

Some people with a degenerative form of arthritis may need long-term treatment for their symptoms to improve.

The doctor will recommend the best way to manage their symptoms and relieve any pain related to the condition.

It can be difficult for doctors to diagnose pain caused by SI joint arthritis. This is because doctors can mistake it for other conditions.

To diagnose the condition, a doctor can perform the following:

A person may be unable to prevent SI joint arthritis if a chronic health condition causes it. However, they can reduce their risks of developing the condition by:

  • exercising regularly
  • keeping a moderate body weight
  • using pelvic girdle support belt if pregnant
  • adopting good posture
  • avoiding strenuous exercises

The SI joint connects the hip to the pelvis.

Common symptoms of SI joint arthritis include stiffness, swelling, and pain in the SI joint and surrounding connective tissues.

Types of arthritis that can cause SI joint arthritis, includes OA, RA, SLE, AS, PsA, gout, pseudogout, and reactive arthritis.

Other conditions, such as pregnancy, injury, and poor posture, can also cause pain in the SI joint.

To treat SI joint arthritis, a doctor may recommend medication, physical therapy, or surgery.