What is the recommended treatment for a patient with sacroiliitis (M46.1) who has not responded to conservative treatment, with pain lasting over 1 month and intensity above 4/10?

Treatment Approach for Refractory Sacroiliitis

For a patient with sacroiliitis (M46.1) who has failed conservative treatment with pain lasting over 1 month and intensity above 4/10, initiate TNF inhibitor therapy (etanercept, adalimumab, infliximab, or golimumab) as the next therapeutic step, with fluoroscopy-guided corticosteroid SI joint injections as an adjunctive option for isolated active sacroiliitis. 1, 2

Immediate Next Steps

Biologic Therapy (Primary Recommendation)

• TNF inhibitors are strongly recommended as first-line biologic therapy for active sacroiliitis that persists despite NSAIDs, with no particular TNF inhibitor preferred over another 1, 2
• This recommendation applies after at least a 1-month trial of NSAIDs has failed to control symptoms 2
• TNF inhibitors are preferred over IL-17 inhibitors (secukinumab or ixekizumab), which serve as conditional alternatives for patients with contraindications to TNF inhibitors or after TNF inhibitor failure 1, 2

Local Corticosteroid Injections (Adjunctive Option)

• For isolated active sacroiliitis despite NSAID treatment, fluoroscopy-guided intra-articular corticosteroid injections are conditionally recommended 1, 2
• Injections should ideally be performed with imaging guidance (fluoroscopy, ultrasound, or CT) in experienced centers 2
• Expected outcomes: approximately 54.5% of patients achieve greater than 50% pain reduction, with relief lasting 2-6 months 1
• If initial injection provides ≥50% relief for ≥2 months, repeat therapeutic injections are appropriate 1, 3

Evidence Supporting Corticosteroid Injections

The research evidence demonstrates consistent efficacy:

• 90.9% of patients reported good improvement within one month after fluoroscopy-guided betamethasone injection 4
• Mean VAS scores reduced from 5.85 at baseline to 3.30 at four weeks, 3.30 at eight weeks, and 3.00 at six months with triamcinolone and ropivacaine combination 5
• Significant improvements in Roland-Morris functional questionnaires from baseline (13.56) to six months (8.26) 5
• Fluoroscopy-guided corticosteroid injection produces significant reduction in pain and disability at two and four weeks compared to placebo 6

Treatment Algorithm for Inadequate Response

If TNF Inhibitor Fails

• For primary non-response to first TNF inhibitor: switch to IL-17 inhibitor (secukinumab or ixekizumab) 2
• For secondary non-response to first TNF inhibitor: switch to a different TNF inhibitor 2
• Do not switch to the biosimilar of the first TNF inhibitor if that TNF inhibitor was ineffective 2

If Corticosteroid Injections Provide Inadequate Relief

• Trial prolotherapy with dextrose (64% achieve 50% pain relief at 6 months, superior to corticosteroid injections at 27%) 1, 3
• Continue focused pelvic stabilization physical therapy with supervised exercise 1, 3
• Consider cooled radiofrequency ablation 3

Mandatory Concurrent Therapy

Physical Therapy

• Active physical therapy interventions (supervised exercise) are strongly recommended over passive interventions (massage, ultrasound, heat) 1, 2
• Land-based physical therapy is conditionally recommended over aquatic therapy 1, 2
• Physical therapy should be continued throughout treatment 1

NSAID Management

• Continue on-demand NSAID treatment (conditionally recommended over continuous treatment for stable disease) 2
• For patients at high risk of gastrointestinal adverse events, selective COX-2 inhibitors are recommended when available 2

Critical Treatments to AVOID

• Systemic glucocorticoids are strongly recommended against for ongoing management of axial disease 1, 2
• Short-term oral glucocorticoids (<3 months) may only be conditionally considered as bridging therapy during biologic initiation in cases of high disease activity 2
• Methotrexate monotherapy is strongly recommended against for sacroiliitis 2
• Conventional DMARDs (sulfasalazine, methotrexate, leflunomide) are not recommended for purely axial disease 2

Documentation Requirements Before Injection

If proceeding with SI joint injection, ensure:

• Imaging confirmation of bilateral sacroiliitis (plain radiographs initially, MRI if equivocal showing bone marrow edema or inflammation) 7, 1
• At least 3 positive provocative maneuvers (thigh thrust, Fabers, lateral compression) providing 94% sensitivity and 78% specificity 1, 3
• Exclusion of lumbar spine pathology (disc herniation, stenosis, facet disease) 3
• Pain localized to sacrum/buttock/posterior thigh without radicular symptoms to the foot 3
• At least 6 weeks of failed conservative treatment with NSAIDs and physical therapy 1

Important Caveats

Common pitfall: A single therapeutic corticosteroid injection does not meet diagnostic criteria for surgical fusion consideration—dual diagnostic blocks with >70-80% concordant pain relief are required before any surgical intervention 1, 3

Diagnostic consideration: If there is a significant change in disease course or lack of response to treatment, consider causes other than inflammation such as spinal fracture, which occurs more frequently than expected in axSpA patients and may occur without preceding trauma 7

Biologic therapy monitoring: Evaluate response after at least 12 weeks of TNF inhibitor therapy using ASDAS (Ankylosing Spondylitis Disease Activity Score) or BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) 7