Both sacroiliitis and arthritis end with the suffix “itis,” which means inflammation. Sacroiliitis affects the sacroiliac (SI) joint, and while it’s not a type of arthritis, it is linked to inflammatory arthritis of the spine. ¹ Baronio M, Sadia H, Paolacci S, et al. Etiopathogenesis of sacroiliitis: implication for assessment and management. Korean J Pain. 2022;33(4):294-304. http://doi.org/10.3344/kjp.2020.33.4.294

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What is the difference between sacroiliitis and arthritis?

Illustration representing pain pattern of SI joint pain in the lower back and thigh on the right side.

Sacroiliitis pain can present in the lower back, buttocks, and legs.

Sacroiliitis refers to the inflammation of the SI joint, which is located on each side of the sacrum (lower spine) and connects the base of the spine to the hip bone. ¹ Baronio M, Sadia H, Paolacci S, et al. Etiopathogenesis of sacroiliitis: implication for assessment and management. Korean J Pain. 2022;33(4):294-304. http://doi.org/10.3344/kjp.2020.33.4.294

This condition causes the SI joint to become inflamed due to trauma, infection, pregnancy, and arthritis. ¹ Baronio M, Sadia H, Paolacci S, et al. Etiopathogenesis of sacroiliitis: implication for assessment and management. Korean J Pain. 2022;33(4):294-304. http://doi.org/10.3344/kjp.2020.33.4.294
Sacroiliitis typically causes a dull, aching pain that presents acutely and often has a sudden onset in the lower back, buttocks, and legs that increases when sitting for long periods and/or during activities that involve bending or twisting at the hip. ¹ Baronio M, Sadia H, Paolacci S, et al. Etiopathogenesis of sacroiliitis: implication for assessment and management. Korean J Pain. 2022;33(4):294-304. http://doi.org/10.3344/kjp.2020.33.4.294

Does sacroiliitis lead to arthritis?

illustration of SI joint arthritis on the left side of the pelvis.

Sacroiliitis can present as a symptom of underlying arthritis.

Sacroiliitis is often associated with certain types of inflammatory arthritis that affect the spine, including ankylosing spondylitis, ⁴ Wenker KJ, Quint JM. Ankylosing Spondylitis. [Updated 2022 Apr 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470173/ psoriatic arthritis, and rheumatoid arthritis. ⁵ Buchanan BK, Varacallo M. Sacroiliitis. [Updated 2022 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448141/ In these cases, sacroiliitis is considered a symptom of underlying arthritis. ⁵ Buchanan BK, Varacallo M. Sacroiliitis. [Updated 2022 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448141/

However, sacroiliitis can also occur independently without being linked to another form of arthritis. ⁶ O’Shea FD, Boyle E, Salonen DC et al. Inflammatory and degenerative sacroiliac joint disease in a primary back pain cohort. Back Pain. 2010;62(4):447-454. https://doi.org/10.1002/acr.20168

Common non-arthritic causes of sacroiliitis include ¹ Baronio M, Sadia H, Paolacci S, et al. Etiopathogenesis of sacroiliitis: implication for assessment and management. Korean J Pain. 2022;33(4):294-304. http://doi.org/10.3344/kjp.2020.33.4.294 :

Macro trauma. A fall or accident that results in trauma to the pelvis or lower back can cause sacroiliitis.
Micro trauma. Variations in how an individual bends and mechanically navigates their environment can lead to micro-injuries within the sacroiliac ligaments.
Overuse. Repetitive activities involving the lower back and pelvis, such as long-distance running or cycling, and manual labor involving repetitive twisting can increase pressure on the SI joints.
Pregnancy. The sacroiliac joint can become strained or inflamed during pregnancy due to increased weight and pressure on the pelvis, causing pain.

Pregnancy is a common cause of SI joint pain flare-ups.

Gait abnormalities. Abnormalities in how a person walks or stands can place extra stress on the SI joint(s) and cause inflammation. Long strides in a gait cycle can irritate the sacroiliac joints. The most common cause of gait abnormalities is leg length discrepancy.
Infection. In rare cases, a bacterial or viral infection can cause sacroiliitis.

Prolonged inflammation of the SI joint can cause damage to the joint over time, which can increase the risk of developing arthritis.

It’s important to note that not all cases of sacroiliitis lead to arthritis, and the development of arthritis can vary from person to person. ⁶ O’Shea FD, Boyle E, Salonen DC et al. Inflammatory and degenerative sacroiliac joint disease in a primary back pain cohort. Back Pain. 2010;62(4):447-454. https://doi.org/10.1002/acr.20168 Early diagnosis and treatment of sacroiliitis can help prevent or slow down the development of arthritis.

If you experience symptoms of sacroiliitis or arthritis, it is important to speak with a physician trained in diagnosing and treating musculoskeletal pain, who can help determine the underlying cause of your symptoms and develop a treatment plan that is right for you.

View this Osteoarthritis Infographic in our Infographic Center.

What is osteoarthritis?

Osteoarthritis occurs when the cartilage tissue protecting the end of a bone breaks down. Any joint can develop osteoarthritis, which is most common in the hands, knees, and hips. Joint pain from osteoarthritis may be mild and annoying, or severe and debilitating.

What signs are associated with osteoarthritis?

While the underlying causes of osteoarthritis are still being investigated, the signs of osteoarthritis are fairly well recognized.

Damaged, thinned, or missing cartilage
Bone spurs, bone cysts, bone marrow lesions, or hardened bone tissue
Inflammation of the synovial membrane

What are common symptoms of osteoarthritis?

Referred pain. While pain is usually felt in the affected joint, it is possible for the pain to be referred to other areas of the body.
Joint stiffness. Stiffness may be most noticeable first thing in the morning or after a prolonged period of inactivity.
Loss of range of motion. The range of motion may be limited or lost because of bone spurs or other tissue changes.
Swelling. The joint may swell due to buildup of excess fluid. If the swelling is moderate to severe, the joint may feel warm.
Crepitus. Any grinding, grating, creaking, cracking, crunching, or popping that occurs when moving a joint is called crepitus.
Bone spurs. Friction and pressure between a joint’s bones can lead to bone degeneration and the growth of bone spurs.
Loss of function. The joint may occasionally lock up or be unable to handle stress or strain.
Joint deformity. Bone spurs or other changes in the joint may lead to a noticeable physical deformity.

What are the common ways to treat osteoarthritis?

Nonsurgical Treatments

A doctor may recommend one or a combination of the following nonsurgical or self-care options:

Physical Therapy
Cold or Warm Compress
Steroid Injections
Medication
Periodic Rest

Surgical Treatment

When joint damage causes moderate to severe pain and restricts mobility, surgery may be recommended.
Joint Replacement (Arthroplasty)

This information is not intended or implied as a substitute for medical advice, diagnosis or treatment. All content, including text, graphics, images or other information provided is intended for general information purposes only. Always consult with your physician for diagnosis or treatment.

Learn more:

Sacroiliitis Treatment

Osteoarthritis of the Spine

Dr. Lisa Covey is a chiropractor and the director of FitWell Chiropractic Sports Medicine in San Francisco, California. She specializes in all types of soft tissue and repetitive strain injuries of the spine and the extremities. She incorporates both Active Release Techniques (ART) and Graston therapeutic techniques.