What is SIJ pain?

What is SIJ pain?

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The past few weeks the Health and Fittness blog has talked a lot about low back pain

But is your back pain actually lower than your back? Does it sit over those bumpy bones at the back of the hip?

This area is known as the sacroiliac joint (SIJ). The SIJ is a stiff fibrous joint that connects the hips to spine. Its main job is to transfer the weight carried by the trunk through to the hips and legs when we stand up, walk and lift.

Pain in this area can effect 15-30% of people with low back pain! SIJ pain can be either mechanical or inflammatory in nature. Being of a mechanical nature simply means that it is pain that has been caused by a physical injury or dysfunction to the joint and surrounding muscles.  In contrast, pain which is inflammatory in nature can indicate underlying inflammatory conditions such as ankylosing spondylitis.

 It is important to identify the difference between these two types of SIJ pain, so you can get the right treatment from the right health practitioner. This could be a physiotherapist, a rhuemotalogist or a combination of the two. Treatment offered by a physiotherapist should include advice on activity modification, appropriate exercises to restore flexibility and control to back movement and manual therapy as required.

So how do you determine what is inflammatory or mechanical SIJ pain?

Mechanical SIJ pain most commonly occurs when the muscles that are attached to this joint, such as the deep buttock muscles and deep abdominal muscles, fail to work effectively. As a result, the body's weight is not transferred properly between the trunk and the legs and it gets “stuck” at the SIJ. If there is increased weight being carried at the SIJ for prolonged periods of time, pain can occur due to increased stress being placed on its ligaments.

Ligaments are strong fibrous bands that are designed to reinforce joints of the body. They are not only found at the SIJ but also at the ankle, elbow and wrist. The posterior sacroiliac, the sacrotuberous and the sacrospinus ligaments are the most commonly injured at the SIJ. They are found at the top and bottom corners of the sacrum and work hard to stop increased bending or gliding of the SIJ.

This process can occur as a result of a sudden increase body mass, poor sitting or standing postures or a fall on to the hip or back.

 Pregnancy can indirectly cause mechanical SIJ pain. This is due to the release of the hormone, relaxin, into the body to make ligaments at the SIJ stretchy and ready for child birth.

Typical mechanical SIJ pain is found on one side of the sacrum only. Most people with this injury, find movement painful. Things like walking, climbing stairs and prolonged activity are common aggravating activities. Resting and sitting on the other hand will relieve most mechanical SIJ issues.

On the flip side, inflammatory SIJ pain behaves differently. Pain can be found at both sides of the SIJ or just one. It usually starts without any significant event or change to lifestyle. Most people with inflammatory pain will have had a long history of low back/ SIJ pain that never seems to completely improve despite lots of treatment from physios, chiros, massage and exercise.

Unlike mechanical pain, inflammatory SIJ pain doesn’t like rest and is worst at night or in the morning after a night’s sleep. Prolonged sitting or standing also tends to aggravate inflammatory SIJ pain. Gentle exercises, such as stretching and walking will improve inflammatory SIJ pain.

The cause of inflammatory SIJ pain is due to sacroillitis. This is an inflammatory process that occurs within the SIJ itself. If left untreated this can cause joint erosion or calcification and in some conditions it may continue upwards to effect the spine. In the case of sacroilltis this can occur with other systemic symptoms such as IBS, uveitis or dactylitis. Conditions that feature inflammatory SIJ pain include Ankylosing Spondylitis, Psoariatic Arthritis and Spondyloarthopathy.  To read more about these conditions, check out our website here.

Does your SIJ pain sound inflammatory or mechanical?

Sometimes it can be hard to tell. Differentiating between the two types is something that the physiotherapy team at BJCHealth are trained to do. If you want some clarification on what is the cause of your SIJ pain and who should treat it, why not book in a back check today.

Book a FREE back check

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