Sacroiliac Joint Pain

Patients with sacroiliac joint pain typically complain of deep-seated lower back and buttock symptoms. Patients can sometimes localise their symptoms very specifically, inferior and medial to the PSIS (exact location of the SIJ); when present, this can be helpful diagnostically and is termed the Fortin finger test. Localised pain is not always reliable, however, as referral symptoms from the sacroiliac joint can be extensive.Sources: The Fortin finger test: an indicator of sacroiliac pain – PubMed (opens in a new tab); Diagnosing Sacroiliac Joint Pain – PubMed (opens in a new tab)

There is more commonly an inciting event in patients with sacroiliac joint pain when compared to facet or discogenic causes. Falls, motor vehicle collisions, repetitive stress from sporting activities, especially those requiring excessive rotational movements, and pregnancy are often described.Source: Inciting events initiating injection-proven sacroiliac joint syndrome – PubMed (opens in a new tab)

Diagnosing the sacroiliac joint as a cause of a patient’s lower back pain is often challenging. There are clear similarities in its presentation when compared to more common causes of axial lower back pain, such as discogenic or facet.

As described previously, localised SIJ pain, inferior and medial to the SIJ, is helpful but not diagnostic. Clinically and with plain radiographs, the hip should be cleared as a potential cause of posterior hip/buttock pain. Neurologically, the patient should be intact; if there are any progressive leg symptoms, especially in a dermatomal distribution, an alternative diagnosis should be considered.Source: Diagnosing Sacroiliac Joint Pain – PubMed (opens in a new tab)

There are some clinical tests that have been suggested to stress the SIJ, but their sensitivity and specificity in attributing pain to the sacroiliac joint remain poor. Imaging can often add little to the diagnosis. MRI can be helpful in sacroiliitis that can be clearly seen on STIR sequences and is highly suggestive of spondyloarthropathy. It can also be helpful at excluding other potential diagnoses, including sacral insufficiency fractures/lesions and benign and aggressive bone lesions in the pelvis. X-rays are usually underwhelming and may show some degeneration in the sacroiliac joint, which is a common finding in the asymptomatic population. Although no true ‘gold standard’ diagnostic test exists, an image-guided injection of local anaesthetic +/- steroid into the sacroiliac joint can be helpful in confirming the sacroiliac joint as a cause of pain.Sources: Diagnostic Accuracy of Clusters of Pain Provocation Tests for Detecting Sacroiliac Joint Pain: Systematic Review With Meta-analysis – PubMed (opens in a new tab); Sacroiliac joint pain: a comprehensive review of epidemiology, diagnosis and treatment – PubMed (opens in a new tab); The prevalence of sacroiliac joint degeneration in asymptomatic adults – PubMed (opens in a new tab); Use of Diagnostic Injections to Evaluate Sacroiliac Joint Pain – PMC (opens in a new tab)

For the mainstay of isolated lower back pain, there are no surgical indications (excluding traumatic causes due to spinal instability, malignancies or infectious causes).

• Period of relative rest. For acute episodes of SIJ/buttock pain (without red flag symptoms/non-inflammatory), the vast majority will self-resolve within 12 weeks without any medical input.Source: Sacroiliac Joint Pain – StatPearls – NCBI Bookshelf (opens in a new tab)
• For patients with inflammatory back pain (under the age of 40, worse at rest, better with movement, early morning stiffness lasting longer than 30 minutes, with or without underlying psoriasis or inflammatory bowel disease) with confirmed sacroiliitis on MRI, these patients will be referred to rheumatology for review and treatment.Source: Ankylosing Spondylitis – StatPearls – NCBI Bookshelf (opens in a new tab)
• Physiotherapy and exercise. This can be helpful for both mechanical and inflammatory causes. The best exercises are the ones the patient will be compliant with. Evidence does not support one specific rehab/exercise programme over another.Source: Effectiveness of exercise intervention in relieving symptoms of ankylosing spondylitis: A network meta-analysis – PubMed (opens in a new tab)
• An image-guided injection of local anaesthetic and steroid can be both diagnostic and therapeutic for patients with refractory symptoms that have not improved with initial conservative options.Source: Stratification of Sacroiliac Joint Pain Patients and the Efficacy of Ultrasound-Guided Injection Treatment: A Retrospective Study – PMC (opens in a new tab)

Surgical management

Surgery for sacroiliac joint pain is rarely indicated, but if a patient experiences severe symptoms (that are non-inflammatory in nature) that have failed conservative management but had an initial response to an image-guided sacroiliac joint injection, arthrodesis (fusion) may be considered. Unfortunately, even with fusion, refractory symptoms of varying degree are still common.Sources: Minimally Invasive Posterior SI Joint Fusion with a Novel Cortical Allograft: Real-World, Long-Term, Outcomes from a Large, Multisite US Cohort – PMC (opens in a new tab); Surgical Outcomes of Patients with Sacroiliac Joint Pain: An Analysis of Patients with Poor Results Regarding Activities of Daily Living – PMC (opens in a new tab)