By Marc Darrow, MD, JD
Pain near the sacroiliac (SI) joint can be frustrating. A patient may have pain low in the back, across one buttock, or toward the hip and receive an MRI report describing lumbar disc degeneration. Another clinician may call the same symptoms “SI joint dysfunction.” If physical therapy or an injection does not help, what should happen next?
In my practice, the answer begins with a fresh look at the diagnosis. The SI joint connects the lower spine to the pelvis, but several nearby structures can cause pain in the same region. A failed treatment is a reason to reassess; by itself, it does not prove that the original diagnosis was wrong.
Is the SI joint actually causing the pain?
The lumbar discs and nerves, facet joints, hip joint, and tissues surrounding the pelvis can all contribute to pain around the SI joint. Pain location alone cannot reliably distinguish them. An MRI can reveal a disc abnormality or arthritis, but an image finding does not automatically identify the structure responsible for a person’s symptoms.
One older study discussed in the original version of this article found that relatively few patients referred with pain in the SI region had the SI joint identified as their primary pain source after further evaluation. That result is a useful reminder to examine the lumbar spine and hip. It should not be applied as a universal estimate: other studies and clinical guidelines recognize SI joint complex pain as an important cause of chronic low back pain. (1) (2)
How do doctors evaluate suspected SI joint pain?
A useful evaluation combines the patient’s history, a physical examination, and a review of competing explanations. A clinician may perform several provocation tests: specific movements that place stress on the SI region and attempt to reproduce familiar pain. A cluster of positive tests can raise suspicion, but it is not a perfect confirmation. A negative group of tests can be particularly helpful in making SI joint pain less likely. (2)
Imaging helps identify other conditions, including significant hip disease, inflammatory sacroiliitis, or a lumbar problem that may require different care. For ordinary mechanical SI joint complex pain, however, imaging alone is often inconclusive. An image-guided injection of local anesthetic inside the joint can help assess pain arising there. It may not identify pain from ligaments and other tissues outside the joint, and even a positive response must be interpreted alongside the examination. (2) (3)
That distinction matters if you are considering an invasive procedure. The question is more precise than “Do I have SI dysfunction?” It is: “Which structure is most likely producing my pain, and what findings support treating that structure?”
Why might an SI joint injection fail?
A corticosteroid injection can reduce pain for some well-selected patients, generally for a limited period. Its effect varies. Incomplete relief may mean that the injection did not reach the relevant pain source, that pain also arises from the lumbar spine or hip, or that the treatment did not provide lasting benefit despite a reasonable diagnosis. It does not justify saying that steroid injections never work or that every patient who fails one has been misdiagnosed. Current consensus guidelines find evidence of short-term relief in selected patients, while recognizing limits in durability and study quality. (2)
If an injection did not help, I would revisit the pain pattern, examination findings, imaging, and details of the procedure before recommending another injection or surgery. For some patients the next step is a different rehabilitation plan; for others, a more focused diagnostic assessment is appropriate.
What are the nonsurgical treatment options?
Rehabilitation usually starts with a plan tailored to the patient’s movement, strength, and tolerance. This can include progressive exercise, work on hip and trunk strength, and changes to activities that repeatedly provoke pain. A 2025 review of randomized trials reported improvements in pain with exercise and some hands-on physical therapy approaches, although the studies differed and no single program is right for everyone. (4)
Radiofrequency ablation uses heat to interrupt selected pain signals carried by small nerves around the posterior SI joint. A randomized comparative study found better outcomes at three months with cooled radiofrequency ablation than with standard medical management among carefully selected patients who had responded to diagnostic blocks. This is an option to discuss after an appropriate workup, not a substitute for identifying the pain source. A 2026 analysis also favored several radiofrequency approaches over comparators, but rated the overall certainty of its evidence low to very low. (5) (6)
What about regenerative injections?
Platelet-rich plasma (PRP) uses a concentration of platelets prepared from the patient’s own blood. Some small studies suggest PRP or dextrose prolotherapy may help selected people with SI joint complex pain. The 2025 multispecialty guidelines describe the evidence for at least three months of relief as weak. We do not yet have strong evidence that PRP repairs an injured SI ligament, regenerates the joint, or consistently outperforms established care. Research on bone marrow products for this condition is even more limited. These options require a frank discussion of uncertainty, cost, procedural risks, and the proposed injection target. (2) (7)
Do bone marrow cells, cord blood, or Wharton’s jelly treat SI joint pain?
These are distinct products, so I would not group them all under the label “stem cell therapy.” Bone marrow aspirate concentrate (BMAC) is made from a patient’s own marrow and contains a mixture of cells and other components; it is not a purified stem cell injection. A 2025 systematic review considered the small body of research on cell-based SI joint injections, but there is no convincing controlled evidence that BMAC reliably repairs SI joint ligaments or produces durable relief specifically for SI joint pain. (7)
One prospective study of severe lumbar degeneration reported improvement after bone marrow concentrate treatment, but injections were directed at several possible pain sources, including discs, facet joints, nerves, and sometimes the SI joint. Because the treatments were combined and the study was open label, it cannot tell us whether an SI injection itself worked. (8)
Umbilical cord blood and Wharton’s jelly are different again. Cord blood is the blood collected from the cord; Wharton’s jelly is connective tissue within the cord. Laboratory work on cells isolated from Wharton’s jelly is biologically interesting, but it does not demonstrate that an off-the-shelf Wharton’s jelly injection contains living stem cells or treats SI joint pain. (9)
Ligaments help stabilize the pelvis and may be involved in some patients’ pain. That is a reason to consider them during the examination, not proof that every persistent case is a ligament injury or that an injection will rebuild damaged tissue.
When should SI joint fusion be considered?
Fusion permanently limits movement across the SI joint. It may be discussed for persistent, disabling, carefully confirmed SI joint pain after an adequate trial of less invasive care. The diagnosis and expected benefit deserve close scrutiny. One sham-controlled randomized trial could not establish superiority of minimally invasive SI joint fusion over a sham procedure at six months. This finding does not settle every question about every fusion technique or patient group, but it supports a careful discussion of benefits, alternatives, and uncertainty before surgery. (10)
SI joint pain can also appear after lumbar fusion, so new pain near the pelvis following back surgery should be evaluated on its own merits rather than assumed to be a recurrence of disc pain. (3)
Do you have questions about Sacroiliac Joint Dysfunction?
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References
- Study of primary pain generators among patients with suspected sacroiliac joint pain. Clin Spine Surg. 2019. PMID: 30379658.
- McCormick ZL, et al. Consensus practice guidelines on sacroiliac joint complex pain from a multispecialty, international working group. Pain Med. 2025;26:817–917.
- Sayed D, et al. American Society of Pain and Neuroscience best practice guideline for the treatment of sacroiliac disorders. J Pain Res. 2024.
- Jangra P, Kaur J, Malik M, Rani M. A systematic review and meta-analysis of randomized controlled trials on the effect of various therapeutic interventions on sacroiliac joint dysfunction. J Bodyw Mov Ther. 2025;45:627–638.
- Cooled radiofrequency ablation versus standard medical management for chronic sacroiliac joint pain: a multicenter, randomized comparative effectiveness study. Reg Anesth Pain Med. 2024. PMID: 37407279.
- Park JH, et al. Interventional treatments for sacroiliac joint pain: a systematic review and network meta-analysis. Reg Anesth Pain Med. 2026. doi:10.1136/rapm-2026-107633.
- A systematic review of sacroiliac joint injections of platelet-rich plasma and stem cells. 2025. PMID: 40095122.
- Evaluation of the Effectiveness of Autologous Bone Marrow Mesenchymal Stem Cells in the Treatment of Chronic Low Back Pain Due to Severe Lumbar Spinal Degeneration: A 12-Month, Open-Label, Prospective Controlled Trial. Pain Physician. 2022. PMID: 35322978.
- Comparative Characterization of Cells from the Various Compartments of the Human Umbilical Cord Shows that the Wharton’s Jelly Compartment Provides the Best Source of Clinically Utilizable Mesenchymal Stem Cells. 2015. PMID: 26061052.
- The effect of minimally invasive sacroiliac joint fusion compared to sham operation: a double-blind randomized placebo-controlled trial. 2024. PMID: 38328752.