Sources checked October 18, 2026. This page describes anatomy, evaluation and selected original studies. It does not diagnose pain or recommend a treatment. The source-check date is not a medical-review date.
Where are the SI joints?
There are two sacroiliac joints, one on each side of the sacrum at the base of the spine. Ligaments connect the bones. Mayo Clinic describes pain commonly felt in the lower back or buttock, sometimes extending into the thigh or leg.[4]
This page concerns the sacroiliac region, not every cause of back pain. A treatment name and a pain location are different pieces of information. Keep the clinician's proposed diagnosis separate from the procedure being discussed.
How do clinicians investigate SI joint pain?
Mayo Clinic describes a history and physical examination, with imaging sometimes used to investigate the source. When the diagnosis remains unclear, an anesthetic injection can provide additional diagnostic information.[4]
Ask what each finding supports and what it leaves uncertain. A useful appointment question is: "What else could explain this pain location?" This is a discussion prompt, not a self-diagnosis checklist.
The research populations below were selected differently. Chen's trial required more than 80% pain relief after a diagnostic block; Peckham's trial required at least 50%. Those are study-entry rules, not a universal diagnostic threshold or a protocol for readers.[1][5]
What have SI joint injection studies measured?
The following are selected original comparisons, not a pooled estimate or a complete systematic review. Each summary keeps the intervention, comparison, follow-up and measured result together. Full-text and abstract-only access are labeled so that missing methods stay visible.
What did the 2026 CT-guided PRP trial report?
Peckham and colleagues enrolled 44 adults in a single-blind randomized comparison of CT-guided platelet-rich plasma (PRP) and steroid/anesthetic injections. At three months, 40 participants remained in the analysis, 20 per group. Mean numeric pain-score changes were -3.0 with PRP and -1.8 with steroid/anesthetic; the between-group comparison had P=0.24. The corresponding proportions with at least 50% pain-score reduction were 60% and 35%, P=0.11.[5]
Both comparisons were statistically nonsignificant. That is not evidence that the treatments are equivalent. This summary uses the original author abstract; three-month follow-up does not establish longer-term outcomes.[5]
What did Chen's double-blind trial measure?
Chen and colleagues randomized 26 adults to PRP or corticosteroid injections and followed pain ratings and Oswestry Disability Index scores for six months. At one month, Table 1 records at least 50% pain reduction in 3 of 14 PRP participants and 8 of 10 steroid participants, P=0.011. The six-month responder comparison was not statistically significant, P=0.141.[1]
The full text, published online in 2021 and in a 2022 issue, was read through an archived publisher copy. Missing six-month data excluded that visit from the repeated-measures analysis. Scale wording and one six-month denominator are inconsistent within the paper; no corrected values are invented here. Neither arm was a placebo group.[1]
What did Singla's ultrasound-guided study measure?
Singla and colleagues randomized 40 people with chronic low-back pain attributed to SI-joint pathology in an open trial with blinded endpoint assessment. At three months, median visual-analog pain scores were 1 with PRP and 5 with steroid, P=0.0002. Disability and health-survey scores were also recorded.[6]
These are endpoint scores, not mean individual improvements. This summary uses the original author abstract, indexed with a December 2016 publication date. The open design, short follow-up and different preparation and guidance methods matter when comparing it with the other trials; the results are not interchangeable.[6]
What did the prolotherapy trial measure?
Kim and colleagues recruited 23 participants to dextrose prolotherapy and 25 to steroid injection in a randomized Korean hospital trial published in 2010. Pain and disability were measured at baseline, two weeks and monthly afterward. The two-week between-group comparison was not significant. At 15 months, Kaplan-Meier estimates for at least 50% pain relief were 58.7% and 10.2%, respectively, with log-rank P<0.005.[2]
Those are time-to-event estimates, not simple proportions of everyone recruited. Only the original author abstract was accessible. It does not name the scoring instruments, and full-text attrition and blinding details remain unverified. This small active-comparator trial was not a placebo comparison.[2]
Why does the comparison group matter?
A separate 2024 trial by Randers and colleagues randomized 63 participants to SI-joint fusion or sham surgery. All supplied the six-month primary pain outcome. Mean reductions were 2.6 and 1.7 points on a 0-to-10 scale; the reported between-group difference was -1.0 points, with a 95% confidence interval of -2.2 to 0.3 and P=0.13.[3]
This was a superiority trial, not an equivalence trial. Its selected population and six-month blinded comparison limit its scope. A surgical comparison cannot establish the result of an injection treatment; it illustrates why the actual control group belongs beside a study's numbers.[3]
What should I ask a clinic about its evidence?
Ask the clinic to name the exact procedure, the proposed diagnosis and the study it is relying on. Then ask whether that study used the same preparation, anatomical target and comparison. Request the paper rather than a success-rate graphic.
Ask how pain and daily function would be recorded, which follow-up dates are included, and who evaluates a change in symptoms. For a written quote, ask what is included in the consultation, imaging, procedure and follow-up, without assuming that one advertised fee covers them all.
For terminology, see the PRP treatment guide and prolotherapy treatment guide. These are background links, not a treatment recommendation.
How can I compare PRP clinic listings?
Regenerated.com's September 2026 export contains 2,082 clinics listing PRP among 9,042 clinic records, across 48 states plus Washington, DC. Source: Regenerated.com clinic export, collected September 2026. This is directory coverage, not a US market-size estimate or a count of clinics confirmed to treat SI joint pain.
Use the PRP clinic directory to compare recorded locations and listing details. State pages include PRP clinics in California and PRP clinics in Texas. Confirm the clinician, exact service and location with the provider. A listing is not an endorsement.