Sacroiliitis
Everything about the causes, symptoms, and the most effective treatments for inflammation of the joint that connects the ilium and the sacrum.
Symptoms and Causes
Sacroiliitis is the inflammation of the sacroiliac joint—that is, the joint where the iliac bones of the pelvis meet the sacrum, which is the lower part of the spine. As a result, it causes pain in the lower back or lumbar region, which can radiate to the buttocks and legs.
Depending on the affected area, it can be classified into three types:
- Right sacroiliitis: affects only the joint on the right side.
- Left sacroiliitis: affects only the joint on the left side.
- Bilateral sacroiliitis: affects both joints.
The difference between sacroiliitis and low back pain (lumbalgia) is that the former affects the joint itself, while the latter affects the muscles or intervertebral discs. In addition, treatment varies in each case. To avoid delays in diagnosis and potential complications, it is advisable to consult a specialist as soon as symptoms appear.
Symptoms
The characteristic symptom of sacroiliitis is pain in the lower back and buttocks that radiates to the front or back of the thigh, sometimes reaching the knee. Symptoms vary depending on the stage of the condition:
- Mild sacroiliitis: lumbar and hip pain, usually intermittent. Inflammation is not visible on imaging tests.
- Moderate sacroiliitis: lower back pain, stiffness, and difficulty walking or standing for prolonged periods. Inflammation becomes visible on imaging.
- Severe sacroiliitis: intense, constant pain that may extend to the pelvis and spine, interfering with daily activities. Inflammation is clearly detectable on diagnostic imaging tests.
In summary, the most common symptoms of sacroiliitis include:
- Lower back pain that may radiate to the buttocks, hips, thighs, or groin area.
- Pain that worsens after long periods of standing, sitting, or climbing stairs.
- Morning stiffness or stiffness after periods of inactivity.
- Limited lumbar movement.
- In chronic cases, palpable inflammation and tenderness in the sacroiliac joint.
Symptoms typically worsen in the following situations:
- While sleeping.
- Sitting for long periods.
- Standing for extended periods.
- Climbing stairs.
- Running.
- Taking long strides.
- Bearing weight on one leg.
- Changing posture.
Causes
The main cause of sacroiliitis is a biomechanical imbalance of the joint, which can occur for various reasons, such as:
- Overweight.
- Inflammatory diseases such as spondyloarthritis or ankylosing spondylitis.
- Poor posture.
- Repetitive microtrauma.
- Frequent heavy lifting.
- Gait abnormalities due to scoliosis, genu valgum (knock knees, where the knees are too close together), genu varum (bowlegs, where the knees are apart and ankles together), or leg length discrepancy, among other conditions.
- Traumatic injuries.
- Weak abdominal or gluteal muscles.
- Shortening of the psoas muscle, which runs from the lumbar vertebrae to the femur.
- Stress.
Risk Factors
The risk of developing sacroiliitis increases in the following cases:
- Pregnancy: hormonal changes make the pelvic joint more flexible to facilitate childbirth, which can lead to instability if the muscles are unable to compensate.
- Arthritis.
- Inflammatory bowel diseases such as ulcerative colitis or Crohn’s disease.
Complications
Sacroiliitis rarely causes complications. However, if the pain becomes chronic, it may restrict certain movements or lead to depression.
Prevention
In most cases, sacroiliitis cannot be prevented. Nevertheless, maintaining a healthy lifestyle helps reduce the risk and minimize symptoms when the condition occurs. Some recommendations include:
- Maintaining a healthy weight.
- Practicing good posture when sitting, standing up, or lifting objects.
- Engaging in moderate physical activity on a regular basis. When done in moderation, walking can be beneficial for improving sacroiliitis symptoms.
- Strengthening abdominal and gluteal muscles.
- Performing stretching exercises.
- Avoiding excessive strain or overexertion.
Which specialist treats sacroiliitis?
Sacroiliitis is diagnosed in the specialties of traumatology and orthopedic surgery and rheumatology. Treatment often involves orthopedic surgery and specialists in physical medicine and rehabilitation.
Diagnosis
Diagnosing sacroiliitis can be challenging, as its symptoms may resemble those of conditions affecting the intervertebral discs or lumbar nerves. Therefore, several tests are often used to confirm its presence.
- Clinical diagnosis: medical history and physical examination are the main diagnostic tools, since imaging tests are not always conclusive.
- Pressure is applied to different points on the hip and buttocks to identify the origin of the pain.
- Gaenslen’s test: with the patient lying on their back and one knee flexed, the leg is pressed toward the chest to determine where pain occurs. The procedure is then repeated with the other leg.
- Anesthetic infiltration: anesthetics are injected directly into the joint to check whether the pain subsides. If it disappears, the diagnosis is confirmed, ruling out vertebral or nerve-related causes.
- Diagnostic imaging tests: MRI, CT scan (computed tomography), or X-ray may be used to assess the condition of the joint, although findings are not always definitive. Imaging can also help determine the degree of involvement:
- Grade 0 sacroiliitis: normal joint.
- Grade 1 sacroiliitis: mild changes such as narrowing of the iliac margin or signs of sclerosis (hardening of the connective tissue protecting joint structures).
- Grade 2 sacroiliitis: signs of sclerosis or localized cartilage erosion.
- Grade 3 sacroiliitis: the disease is clearly visible, with joint space narrowing, subchondral sclerosis, erosions, and partial ankylosis (fusion of bones).
- Grade 4 sacroiliitis: the most severe stage, characterized by residual sclerosis and complete ankylosis of the joint bones.
Treatment
Different approaches can be used to treat sacroiliitis depending on the degree of joint damage and individual patient characteristics. The most common therapies include:
- Conservative treatment: noninvasive approach that usually consists of:
- Lifestyle modifications.
- Temporary rest.
- Use of analgesics.
- Corticosteroid infiltrations every two or three weeks, providing immediate relief.
- Endoscopic treatment: a minimally invasive procedure requiring only two or three small incisions. A high-intensity radiofrequency electrode is used to eliminate lesions and reduce inflammation through heat application. During the same procedure, nerve endings are removed to eliminate pain.
- Surgical treatment: performed only when conservative therapies have failed after at least six months of treatment. The procedure usually involves percutaneous fusion of the joint with titanium implants. Although movement is restricted, symptoms disappear, and patients experience a significant improvement in quality of life.
