SI Joint Dysfunction: The Often-Missed Cause of Back Pain

Reviewed by the Physiotherapy Team at Waterloo Sports Medicine Centre 

Experiencing low back pain that doesn't seem to improve? The source of your pain may not be your spine at all. In some cases, pain originates from the sacroiliac (SI) joint, a commonly overlooked cause of lower back and pelvic pain. 

What Is SI Joint Dysfunction? 

The sacroiliac joints are two joints located where the sacrum (the triangular bone at the bottom of the spine) meets the pelvis. These joints help transfer forces between the upper body and legs and provide stability during activities such as walking, running, and lifting.

SI joint dysfunction occurs when one or both SI joints become irritated, inflamed, or move abnormally, leading to pain and reduced function. 

What Does SI Joint Pain Feel Like? 

Symptoms can vary from person to person but often include: 

• Pain on one side of the lower back or buttock 

• Pain that may radiate into the hip, groin, or upper thigh 

• Pain when standing from a sitting position 

• Discomfort with prolonged sitting, standing, or walking 

• Pain when climbing stairs, rolling in bed, or getting out of a car 

• A feeling of instability or the pelvis being "out of place"

Unlike sciatica, SI joint dysfunction typically does not cause numbness, tingling, or pain that travels below the knee. 

What Causes SI Joint Dysfunction? 

Several factors can contribute to irritation of the SI joint, including: 

• Repetitive bending, twisting, or lifting 

• Pregnancy and postpartum changes 

• Falls or traumatic injuries 

• Leg length differences 

• Muscle weakness or poor movement patterns 

• Arthritis or age-related changes 

• Previous lumbar fusion surgery  

In many cases, SI joint pain develops gradually over time due to repeated stress on the joint. 

Who Is at Risk? 

You may have a higher risk of developing SI joint dysfunction if you: 

• Are pregnant or recently gave birth 

• Participate in sports that involve running or twisting movements 

• Have a history of low back injuries 

• Spend prolonged periods sitting 

• Have reduced core or hip strength 

• Have arthritis affecting the pelvis or spine. 

  
  

How Can Physiotherapy Help? 

Physiotherapy is one of the primary treatments for SI joint dysfunction and focuses on addressing the underlying factors contributing to pain. 

Your physiotherapist may recommend: 

Education and Activity Modification 

Learning how certain movements and positions affect your symptoms and making modifications to reduce stress on the SI joint. 

Manual Therapy 

Hands-on treatment techniques may help improve joint mobility, reduce pain, and restore normal movement patterns.

Exercise Therapy 

Specific exercises can improve the strength and control of the muscles that support the pelvis and lower back, including the: 

• Gluteal muscles 

• Deep abdominal muscles 

• Hip muscles 

• Core stabilizers 

  
  

Mobility and Stretching Exercises 

Improving flexibility in surrounding muscles, such as the hip flexors, hamstrings, and piriformis, can reduce strain on the SI joint. 

Pelvic Stabilization Training 

Exercises that improve coordination and stability of the pelvis can help decrease symptoms and prevent recurrence.

When Should You See a Physiotherapist? 

Consider booking an assessment if you have: 

• Persistent pain in the lower back, buttock, or pelvis 

• Pain when transitioning from sitting to standing 

• Symptoms that worsen with walking, running, or prolonged sitting 

• Recurring episodes of low back pain that have not improved with rest 

• Pain that is affecting work, exercise, or daily activities 

Most people improve significantly with conservative treatment and do not require injections or surgery. 

At Waterloo Sports Medicine Centre, our physiotherapists can assess whether your symptoms may be coming from the SI joint and create an individualized treatment plan to help reduce pain, improve function, and get you back to the activities you enjoy!