Sacroiliac joint degenerative changes are a frequent, yet often overlooked, source of chronic discomfort in the lower back and pelvic region. This condition involves the gradual breakdown of the joint linking the spine to the pelvis, resulting in pain that can significantly impair daily function. The sacroiliac (SI) joint is estimated to be responsible for 15% to 30% of all chronic lower back pain cases. Because its symptoms often overlap with those of other spinal issues, SI joint degeneration is a common cause of misdiagnosis.
Understanding Sacroiliac Joint Degeneration
The sacroiliac joint is a pair of small, sturdy joints connecting the triangular sacrum at the base of the spine to the large ilium bones of the pelvis. Its function is to provide stability and act as a shock absorber, transferring the weight of the upper body to the lower extremities. The joint is reinforced by a complex network of strong ligaments that limit motion, typically allowing only a few degrees of rotation and minimal translation.
Degenerative changes occur when the protective cartilage layer covering the joint surfaces begins to wear away over time, similar to osteoarthritis. As the cartilage erodes, the underlying bone surfaces may rub against each other, causing inflammation and pain. This degeneration can lead to either excessive motion (hypermobility) or stiffness (hypomobility), disrupting the joint’s load-bearing function.
Risk factors often involve biomechanical stress placed on the joint. Age is a factor, as are conditions that alter a person’s walking pattern, such as leg length discrepancies or prior hip and knee issues. Prior lumbar spine surgery, particularly fusion procedures, is a significant cause of increased stress, shifting mechanical forces downward and leading to accelerated degeneration. Trauma, such as a fall or repetitive torsional strain, can also initiate or worsen these changes.
Recognizing the Pain Patterns
Pain originating from sacroiliac joint degeneration typically presents as a deep-seated ache in the lower back and buttock region. Patients often localize the discomfort immediately inferior and medial to the posterior superior iliac spine, an area sometimes identified using the “Fortin finger test.” The pain is frequently one-sided, though it can occur bilaterally, ranging from a dull throb to a sharp, stabbing sensation.
A hallmark of SI joint pain is its referral pattern, which can mimic sciatica by radiating down the back of the thigh and sometimes past the knee. This radiating pain is often described as a deep ache, differentiating it from the burning or tingling sensation typical of nerve root compression from a lumbar disc issue.
Activities that stress the joint and positional changes characteristically influence the pain. Simple daily movements can exacerbate symptoms, such as transitioning from sitting to standing, prolonged standing or sitting, or climbing stairs. Patients may also experience discomfort while sleeping on the affected side or during activities involving asymmetrical weight-bearing, like walking with a wide stride.
Methods of Diagnosis
Accurately diagnosing sacroiliac joint degeneration is challenging because the symptoms closely resemble pain from the lumbar spine and hip. The process begins with a thorough physical examination, where a clinician performs specific provocative maneuvers to intentionally stress the joint.
These provocative tests are performed to reproduce the patient’s pain:
- Thigh Thrust
- Distraction
- Compression
- FABER (Flexion, Abduction, External Rotation) tests
A diagnosis is strongly suggested if three or more of these maneuvers consistently elicit pain directly over the SI joint. While these physical assessments are highly sensitive for identifying SI joint dysfunction, they are not specific enough to confirm the diagnosis alone.
Imaging studies, including X-rays, CT scans, or MRI, are utilized primarily to rule out other conditions like fractures, tumors, or severe lumbar disc pathology. Scans may reveal signs of degeneration, such as joint space narrowing or bone spurs, but the extent of change seen on imaging does not always correlate with the patient’s pain level. The definitive method for confirming the diagnosis remains the fluoroscopically guided diagnostic injection. This procedure involves injecting a local anesthetic directly into the joint under real-time X-ray guidance; if the patient experiences a temporary reduction in pain of 50% or more, the SI joint is confirmed as the primary pain generator.
Conservative and Interventional Management
Initial treatment for sacroiliac joint pain focuses on conservative care. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, are often the first-line medical approach to reduce inflammation and pain. Physical therapy is a major component of conservative treatment, concentrating on stabilization exercises for the core and pelvic girdle musculature.
A physical therapist may utilize manual adjustments to address joint stiffness or bracing with an SI joint belt to provide external support and stability. If conservative strategies fail to provide lasting relief, interventional procedures are considered. These typically include therapeutic intra-articular injections of corticosteroids, which deliver a powerful anti-inflammatory agent directly into the joint space for prolonged pain relief.
For patients experiencing chronic pain that returns after injections, radiofrequency ablation (RFA) may be performed. RFA uses heat generated by radio waves to temporarily interrupt the sensory nerves that transmit pain signals from the SI joint. If all other non-surgical options have been exhausted and pain remains debilitating, minimally invasive sacroiliac joint fusion may be presented as a final option. This surgical procedure stabilizes the joint by fusing the ilium and sacrum together, improving pain and function for appropriately selected patients.