Summary: Sacroiliac (SI) joint pain accounts for about 30% of chronic lower back pain cases but is often overlooked. This article explains its causes, symptoms, and the latest regenerative treatment options.
What is the Sacroiliac Joint?
The sacroiliac (SI) joint is an inconspicuous but highly important body structure. Located at the base of the spine, it connects the sacrum (the triangular bone at the back of the pelvis) to the hip bones. Although its range of movement is extremely limited, it acts as a crucial mechanical shock absorber. When we walk or jump, our lower limbs generate powerful impact and twisting forces. The SI joint absorbs these forces and transfers them safely to the upper body, whilst steadily distributing the weight of the upper body down to our legs.
Why Does Sacroiliac Joint Pain Occur?
To support this mechanical function, the joint is surrounded by a tough network of ligaments and connected to powerful muscle groups. These tissues lock the joint in place to provide stability. However, poor posture, long-term wear and tear, hormonal changes during pregnancy, or accidental trauma can easily cause damage to these ligaments and the joint itself, leading to pain. Medical statistics show that up to 30% of pain in patients with chronic lower back pain actually originates from the SI joint and its surrounding ligaments.
What Are the Symptoms of Sacroiliac Joint Pain?
People suffering from SI joint pain usually experience a sharp or dull ache on one side of their lower back, buttocks, or the back of their pelvis. This pain is particularly noticeable when standing on one leg or changing positions, such as standing up from a seated position, turning over in bed, or exercising. Patients often feel stiffness in the painful area when waking up in the morning. Sometimes, this pain radiates down the back of the thigh. Because these symptoms are very similar to sciatica, SI joint pain is frequently misdiagnosed, preventing many patients from receiving the correct treatment early on.
The Challenge of Diagnosis
Diagnosing SI joint pain is not easy. Although it is the source of 30% of structural lower back pain, it is not often accurately diagnosed in practice. General medical imaging, such as X-rays or magnetic resonance imaging (MRI), can help rule out serious issues like fractures or inflammation, but they are rarely helpful for identifying ordinary joint wear and tear. In addition to carefully listening to your medical history, your doctor will perform a series of clinical physical examinations. Sometimes, to confirm the diagnosis, the doctor will need to inject a local anaesthetic into the SI joint under X-ray guidance. If the pain is significantly reduced following this, the source of the pain can be confirmed.
Treatment Options
For mild cases, your doctor will initially try oral medications or arrange for physical therapy and acupuncture. Because the SI joint is a complex mechanical structure, patients greatly benefit from specific muscle training. Exercises targeted at strengthening the gluteal (buttock) and core muscles help to restabilise the pelvis and improve the way weight is distributed across the joint.
If conservative treatments are ineffective, minimally invasive interventional treatments that do not require surgery should be considered. Traditionally, doctors inject steroids directly into the joint space to reduce inflammation and relieve pain. However, recent research indicates that the pain often involves the ligament group surrounding the joint, and repeated steroid injections can weaken these ligaments over time.
In recent years, new medical research supports the use of regenerative therapies such as Platelet-Rich Plasma (PRP). Under X-ray and ultrasound guidance, doctors precisely inject PRP into the problematic joint and surrounding ligaments to regulate inflammation and promote tissue repair and strengthening. In the long run, this controls pain more effectively than steroids. For extremely severe and stubborn pain, doctors may use a procedure called radiofrequency ablation to safely burn or deactivate the sensory nerves responsible for transmitting pain signals from the joint, thereby achieving lasting pain relief.
Other Causes Not to Be Ignored
While SI joint pain is mostly caused by daily wear and tear, it can also be a warning sign for other serious medical conditions, such as autoimmune diseases or fractures. Therefore, patients should seek professional medical assistance to clarify the exact cause and receive the most appropriate treatment.
Information provided by Dr Lee Yuk Ming, Sunny, Specialist in Pain Medicine
