Continuing Education Activity

Sacroiliac joint injury is a common type of low back pain. Differentiating SI joint pain from mechanical low back pain is essential. This activity outlines the evaluation and management of sacroiliac joint injury and highlights the role of the interprofessional team.

Objectives:

• Identify the etiology of sacroiliac joint injury medical conditions and emergencies.
• Review the appropriate evaluation of sacroiliac joint injury.
• Outline the management options available for sacroiliac joint injury.
• Describe the interprofessional team strategies for improving care coordination and communication to advance sacroiliac joint injury and improve outcomes.

Introduction

Sacroiliac (SI) joint injury is a common cause of low back pain. Posterior pelvic joint pain a common name for SI joint dysfunction. The spine and pelvis are connected by the sacroiliac joint. The SI joint lies between the iliac's articular surface and the sacral auricular surface. When an injury occurs to the SI joint, patients often experience significant pain in their low back and buttock region. The SI joint experiences forces of shearing, torsion, rotation, and tension. Ambulation is heavily influenced by the SI joint, as this is the only orthopedic joint connecting our upper body to our lower body. The joint is a relatively stiff synovial joint filled with synovial fluid. The bones of the sacrum and ilium are coated in hyaline cartilage at their articular surfaces with dense fibrous tissue connecting the ilium and the sacrum. SI joints typically only have a few degrees of motion.

Diagnosing sacroiliac (SI) joint pathology can be challenging. One of the difficulties providers can run into in the evaluation of SI joint injury is in distinguishing between lower lumbar pain (lumbago) from SI joint pain. Specialized tests can be instrumental in making this distinction. It is vital to keep SI joint pain as part of the differential diagnosis of low back pain, with up to 30% of low back pain secondary to the SI joint.[1] Pregnant women experience joint laxity due to hormonal changes, and this is when the SI joint is the most vulnerable to injury. Between the ages 40 and 50, the SI joint fuses decreasing the SI joints' laxity. Fusion and or pregnancy may lead to hypermobility or hypomobility, which may exacerbate SI joint pain. Osteoarthritis is a common cause of SI joint pain.[2][3]

However, there are multiple etiologies and a variety of factors that can contribute to SI joint injury.[3] The overlap in symptoms with various causes of low back pain, as well as the numerous origins of SI joint dysfunction, make it not only a tough diagnose to make but also challenging to treat.[2][3] SI joint injury can be acute but becomes chronic after three months of persistent pain. Chronic SI joint pain occurs when the free nerve endings within the SI joint degenerate or become chronically activated. Pain can be constant or intermittent for SI joint injury. Given the prevalence of mechanical back pain, it is essential to rule out or exclude a lumbar origin of suspected SI joint pain before diagnosis. It is often hard to pinpoint in which cases SI joint dysfunction is the primary reason behind a patient's back pain. Some exceptions include trauma and pregnancy.  

Extra joint mobility of the joint can result in pain in SI joint injury. However, hypomobility is a hallmark of ankylosing spondylitis, a common cause of inflammatory sacroiliac injury. SI joint dysfunction often occurs in unison with mechanical back pain. The sacroiliac joint may also be the site of pain referred from the lumbar vertebra rather than the origin of the patient's pain. For example, degenerative disc disease at the L5-S1 vertebrae may become interpreted at the SI joint, but the source is much higher in the lumbar spine. There are multiple patterns of referral of pain for patients with SI joint injury. Including, the posterior thigh, knee, or foot. The most common site of pain referral is the posterior thigh, seen in 50% of patients.[4][5][6] Complicating SI joint injury management further is a lack of clearly defined guidelines in the diagnosis and management of SI joint pain. MRI is the test of choice in the evaluation of SI joint dysfunction. Furthermore, radiographic-guided anesthetic injection provides a reliable way of determining SI joint pain in many cases.

The sacroiliac joint is a commonly targeted area of treatment of chronic low back pain as well.[7][8] Conservative treatment options for SI joint injury often include physical therapy, home exercises, over the counter pain medication such as NSAIDs or acetaminophen. When conservative management fails, corticosteroid injections and radiofrequency ablative therapies are viable treatment options. In severe, refractory cases, surgery can fuse the SI joint. Patient education is essential in SI joint injury, including posture, proper lifting technique, stretching, and regular exercise. Weight loss helps SI joint pain, as well.

Etiology

Injuries to the sacroiliac joint can occur from various etiologies. 88% of cases of SI joint injury are due to either repetitive microtrauma or acute trauma. There is a high prevalence of SI joint injury in athletes. Separately, 20% of cases are pregnancy-related, while 4% are idiopathic.[9] Trauma in the context of pelvic ring injuries is one example of SI joint injury. Pelvic ring traumatic injuries include three main categories, including anteroposterior compression, lateral compression, and vertical shear-type injuries. Furthermore, injuries to the sacroiliac joint include incomplete SI dislocations, complete SI dislocations, and SI fracture-dislocations.

There are also three types of fractures associated with SI joint injury. A type one fracture is a minor fracture of the anterior aspect of the S2 foramen. This fracture creates a large crescent-shaped fragment that is stable. Less than one-third of the SI joint is involved, and the fracture encompasses the least amount of ligament injury of the three types of fractures. Separately, a type two fractures occur between the anterior aspect of the S1 and S2 foramen. The fracture creates a smaller crescent-shaped fragment compared to the type one injury. Type two fractures occur when one-third to two-thirds of the SI joint is involved. Lastly, a type three fracture encompasses the superior and posterior aspects of the SI joint up to the S1 nerve root. Greater than two-thirds of the sacroiliac joint are involved and include a higher degree of ligament disruption. However, the fracture is typically smaller than a type one or type two fracture. A posterior fracture-dislocation of the SI joint involves variable disruption of the SI ligament complex.[10]

The L5 nerve root crosses the sacral ala 2 cm medial to the SI joint. In the case of injury, the nerve root can be involved causing radicular pain. SI joint innervation occurs via the ventral rami of the L4 and L5 vertebra, as well as the dorsal rami of L5-S2, and the superior gluteal nerve. Injury to these nerves can cause neuropathic SI joint pain. Generalized gluteal pain can be secondary to an injury of the SI joint or local nerves surrounding the SI joint, causing radiculopathy. When the S1 nerve root is directly injured during SI joint injury, it can also create radiculopathy.

Separately, during pregnancy, laxity occurs within many of the joints in the pelvis. The hormone relaxin causes joint mobility during pregnancy. As the pelvis widens during pregnancy, the SI joint becomes more mobile. The expecting mother can experience SI joint pain as the hips rotate, putting stress on the SI joint. Pain can be both unilateral or bilateral during pregnancy.[11][12] SI joint pain during pregnancy is a component of pelvic girdle pain. Patients who experience pelvic girdle pain during pregnancy have high rates of disability than patients suffering mechanical back pain.[13] Risk factors for SI joint dysfunction during pregnancy include forceps delivery, intense contractions, fetal macrosomia. Multiparity, precipitous labor, and a rapid second stage of labor also contribute.[14][15][16][9]

Anatomical variations can lead to SI joint injury as well. An increase in lumbar lordosis, as well as an anterior tilt to the pelvis, can lead to SI joint dysfunction.[17] Patients with underdeveloped musculature can develop postural imbalances, such as a short leg.

Osteoarthritis also plays a role in the development of SI joint pain. Typical of all osteoarthritic joints, joint space narrowing, osteophyte formation, and sclerosis of the SI joint can be seen on x-ray.

Furthermore, inflammatory arthritis can cause SI joint injury. Ankylosing spondylitis is the most common type of inflammatory arthritis of the SI joint. Erosion of the joint can occur over time, leading to disabling pain. Subchondral edema is the earliest sign of sacroiliitis on imaging. Ankylosing spondylitis causes bony erosions of the SI joint. As decay occurs, the joint space widens and becomes sclerotic. Over time the joint fuses as erosion occur across the entire joint.[18] The severity of deterioration is from zero to four grade. Zero being normal, and full fusion of the joint.[19] Higher rates of progression of SI joint injury include active inflammation of the SI joint seen with elevated CRP or on MRI, history of smoking, male sex, and HLA-27 positive testing.

Epidemiology

13% of patients with chronic low back pain have SI joint dysfunction.[20] Between 15 and 30% of low back pain can be attributed to SI joint injury.[20][10]

Lateral compression of the SI joint comprises up to 80% of pelvic rim injuries. Crescent fracture-dislocations of SIJ accounts for 12% of pelvis ring injuries.[10] 

The prevalence of abnormal SI joint movement is 20% in college students and between eight to 16% in asymptomatic individuals.[20] 

Over 80% of patients report clinically significant pain improvement following surgical fusion of the SI joint compared to 25% in the nonoperative group. 3% of patients who undergo fusion surgery require surgical revision. Operative therapy typically requires a 75% improvement following an SI joint diagnostic injection before surgery.[21][22]

History and Physical

The history provided for SI joint pain may look very similar to mechanical back pain, with a few exceptions. Pain is usually localized to the buttock region and may occur with the sensations of numbness, tingling, weakness, pelvic pain, leg instability, and groin pain. The patient often points to the area between their gluteal folds and posterior iliac crests.[23] Walking up and down a flight of stairs, sitting cross-legged, or prolonged sitting or standing may exacerbate symptoms. In an acute injury, pain can be stabbing in nature. Patients often complain they cannot sleep on the affected side of SI joint pain. Pain can also be worse with menstruation. 

Radiation is pervasive in SI joint injury seen in up to 50% of cases, the majority into the lower extremity.[24][25] There are multiple patterns of referral of pain for patients with SI joint injury. Including, the posterior thigh, knee, or foot. Pain in the SI joint often refers to the gluteus muscles and can also radiate into the groin, mimicking hip pain. The most common area of referred pain in cases of SI joint injury is the posterior thigh seen in 50% of patients.[26]

The history of SI joint injury may suggest S1 radiculopathy classically seen in sciatica. Symptoms are reproducible in an SI joint neuropathy of the S1 nerve root. In cases of neuropathic pain, the patient may endorse numbness, tingling burning pain of the posterior leg extending below the knee into the plantar aspect of the foot. The patient may support sensation changes or muscle weakness, depending on the nerve root involved.

A physical exam includes a full musculoskeletal and neurologic exam of the lumbar spine, and bilateral lower extremities are a part of the SI joint injury evaluation. A complete neurological and musculoskeletal exam of the lower extremity should be mostly normal, with muscle strength, sensation, and deep tendon reflexes intact. However, Pelvic asymmetry may be appreciated on the exam. The range of motion testing of the lower extremity is a must for the assessment of SI joint dysfunction. A rectal exam may also be indicated in specific cases. On physical exam, there can be tenderness to the pelvic floor muscles.[27] Furthermore, tenderness along the sacral dimple (the long dorsal ligament) may also be tender to palpation in SI joint dysfunction. 

Sacroiliac joint mobility has been studied, along with the symmetry of the pelvis. Both tests are unreliable in the diagnosis of SI joint dysfunction. The compression of the iliac crest on the side of the patient's pain may reproduce symptoms.[28][29][30] If less pain is elicited during pelvic compression, this points away from lumbar pain and is more suggestive of SI joint injury. In the case of SI joint neuropathy, S1 deep tendon reflexes can be lost, there may be diminished sensation along the S1 dermatome, and the patient may even experience weakness in knee extension and flexion in more severe cases.

Special tests are often utilized in cases of suspected SI joint injury. The Gaenslen test is a special test that can be used to isolate the sacroiliac joint. The patient should be placed in the supine position; their hip flexed to their chest. The provider applies a force to the knee of the flexed hip anteriorly on the ipsilateral side of pain. Simultaneously, the contralateral knee is pushed downward; their opposite leg is allowed to fall off the table. Both SI joints are tested simultaneously. Gaenslen is considered a provocative test, reproducing the patient's symptoms.[31] The supine hip posterior thrust test is another test often used in the assessment of SI joint injury, where pressure is applied to the femur. Trendelenburg testing can help determine if gluteus medius weakness is contributing to SI joint pain. Pain over the contralateral sacroiliac joint during the FABER test is a positive finding for SI joint pathology. When there are three or more provocation tests of SI joint pathology that are positive, the tests have 91 and 78%, sensitivity and specificity, respectively, for SI joint injury. Specificity increases to 87% in the patients who deny midline spine pain.[32]

Evaluation

X-ray is often the first test utilized in SI joint injury. Weight-bearing anteroposterior views are usually all that is needed for the initial radiographic assessment of SI joint pain.[33][34] Radiographs, including AP, inlet, and outlet views, can also be obtained. Sacroiliac views at 25 to 30-degrees of rotation when suspicion is high is also an option when there are nondiagnostic initial x-rays. What is an abnormal X-ray of the SI joint? A standard distance between the sacrum and the ilium is 4 to 5 mm. Narrowing of the joint often leads to injury: joint space narrowing or sclerotic erosion of the joint space are often seen on X-ray. Grade one or two SI radiographs for sacroiliitis have high variability. Thus normal X-rays can be interpreted as SI joint dysfunction.[35][36][19] Twenty to 30% of patients with a seronegative spondyloarthropathy have abnormal X-rays.[18][37][38] MRI is critical in the diagnosis of SI joint injury.[39] Although MRI is the best test for the SI joint injury assessment, it does have a significant false-positive rate in healthy patients.[40]. MRI is usually done without contrast [41]. Findings associated with sacroiliitis, such as bone marrow edema, are seen in over 20% of patients with mechanical back pain on MRI.[42][43][44] Similarly, structural changes, such as erosion of the joint, can be due to various pathologies.[45][46] Scintigraphy can also be used when there is a nondiagnostic MRI.

CT is utilized when MRI is contraindicated or unavailable. Separately, CT of the pelvis with contrast evaluates for vascular and urogenital injures. CT is more sensitive than radiograph but inferior to MRI in detecting SI joint injury.[35] CT is not generally recommended to establish the diagnosis of sacroiliitis unless MRI is contraindicated.[47] However, a low radiation CT is adequate when utilized.[35]

Local anesthetic blocks are a more invasive way to test SI joint pathology when the diagnosis is in question. An ultrasound or fluoroscopy-guided diagnostic injection assesses patient pain before the injection and directly following the injection allowing the physician to see if the pain was alleviated momentarily with short-acting anesthetics. A 75% reduction in pain is suggestive of SI joint pain. Patients who could benefit from an ultrasound-guided diagnostic injection include patients experiencing isolated SI joint pain or pain that is reproducible on three provocative tests.[48][49]

Labs are a part of the assessment for possible inflammatory SI joint injury. When sacroiliitis is seen on pelvic x-ray, a CBC, CRP, and ESR are often part of the workup.

Treatment / Management

Treatment can vary significantly between cases. For example, pregnancy-related SI joint pain often resolved in the months following delivery, while traumatic SI joint injury may require prompt surgical repair.

In acute injury ice, non-steroidal anti-inflammatory should be a part of management unless they are otherwise contraindicated. Muscle relaxers can also be used for SI joint injury such as cyclobenzaprine if the suspected injury is secondary to muscle spasm. Inflammatory sacroiliitis can be treated with TNF inhibitors as well, such as infliximab or etanercept. Weak core muscles, such as oblique muscles can contribute to injury as well. Strengthening of the transverses abdominis, as well as the obliques either through a home exercise program or physical therapy, can help improve SI joint pain. Girdles and braces also help support the core in SI joint dysfunction. Braces have been shown to reduce SI joint pain. Separately, belts can limit the motion of the SI joint. However, limited studies support its clinical significance in SI joint injury.[50][51] Home exercise programs are a more effective initial treatment for SI joint injuries compared to SI joint belts. Manipulation is a possible treatment option, but limited studies assess the clinical effectiveness in SI joint injury.[52] Numerous studies have reviewed the effectiveness of exercise, physical therapy, and stretching in SI joint dysfunction. Neuromuscular proprioceptive training and conditioning studies have also been studied. Generally speaking, physical therapy, home exercise programs, and stretching, as well as a dose of patience and time, will resolve most cases of SI joint pain.[53][54][55][56]

The effectiveness of corticosteroid injections into the periarticular surface of the SI joint is controversial at best.[2][3] Periarticular steroid injection of the SI joints can be done with and without ultrasound guidance in the case of SI joint pain unresponsive to conservative management. However, ultrasound-guided SI joint injections have increased efficiency compared to blind injections.[57] Periarticular steroid injection is superior to lidocaine injections.[57] There are limited studies completed on SI joint corticosteroid injections compared to sham injection. Fluoroscopically guided injections of the sacroiliac joint have had mixed results in terms of diagnosis and management as well.[29][58] Corticosteroid injections of the SI joint can be therapeutic in chronic cases of SI joint osteoarthritis. It is not recommended to do more than three corticosteroid injections should in a year. Cooled radiofrequency neurotomy has better pain relief compared to intraarticular SI joint injections.[3] 

 Radiofrequency denervation is a possible treatment option for refractory, chronic SI joint pain. Rhizotomy (radiofrequency denervation) is often complete after failed corticosteroid injections.[32] However, results are mixed on its efficacy. Consensus shows a likely short-term benefit in the reduction of pain with rhizotomy that reduces over time. High-quality randomized trials are limited. The studies that have been done have limited patient size.[59]

Interestingly at both three to six months, follow-up radiofrequency ablation was shown to have a clinically significant reduction in pain and improvement of function in patients with SI joint injury in one study.[60] It is unclear if one ablative technique is superior to another for SI joint nerve ablation. Radiofrequency ablation is effective without first performing a diagnostic block for SI joint injury.[61] In a study of 228 patients unresponsive to conservative management, radiofrequency ablation was an effective treatment modality, with statistically significant improvement of pain compared to placebo at three months follow up. Yet these results were not considered clinically significant.[62] Spinal cord stimulators implanted into the sacrum can also be used to reduce SI joint pain in chronic reoccurring cases. When all else fails, surgical fusion can be done. 80% of patients endorsed clinically significant pain improvement following surgical fusion. Before surgery, it is required to have a significant improvement of pain following a diagnostic injection.[21][22]

Differential Diagnosis

Common causes of SI joint injury include pregnancy, traumas such as hip fractures, hypermobility, hypomobility, leg length discrepancies, obesity, and surgeries such as lumbar fusion. The differential diagnosis of sacroiliac joint injury includes synovitis, capsulitis, and enthesitis, infection, piriformis syndrome. Osteitis condensins ilii, and malignancies such as multiple myeloma are also a part of the differential. Functional causes can occur with scoliosis or short legs. Posterior sacral ligaments tears can cause pain in SI joint injury.[63][64] Degenerative and mechanical changes also cause SI joint pain. As osteoarthritis develops within the SI joint, causing joint space narrowing. Joint space narrow becomes a source of pain in SI joint dysfunction.

Furthermore, hip osteoarthritis should be considered in addition to SI joint osteoarthritis for low back pain and pelvic pain.[65] Inflammatory arthropathies are various and outside the scope of this article. However, they are a part of the differential diagnosis in SI joint injury. Reactive arthritis and psoriatic arthritis are a few other types of inflammatory arthropathies leading to SI joint injury not mentioned previously. Bechet disease, hyperparathyroidism can also lead to sacroiliitis.[66][67][68] Lastly, disc herniation, lumbar spinal stenosis, and mechanical back pain are part of the differential diagnosis for SI joint injury.

Prognosis

Similar to mechanical back pain, the vast majority of cases of SI joint injury improve with conservative management. Over 75% of cases respond to conservative management and physical therapy.[69] Atraumatic causes of SI joint injury tend to complete the resolution of symptoms compared to traumatic occurrences. Sedentary behavior has worse outcomes.[70][71] Physically active patients have an excellent quality of life with SI joint injury.[72] Stabilization training has been shown to cause a 50% reduction in disability, long term for SI joint injury.[73] The mean duration of symptoms in chronic SI joint injury is 43 months.[23] In cases of chronic refractory SI joint pain, 2% of patients require operative fusion. Progression of SI joint deterioration in sacroiliitis is one to 5% per year.[24]

Complications

The recurrence rate of SI joint injury in over 30% of chronic cases.[74][75] Complications often including difficulty with ambulation, chronic pain, disability, reduction of quality of life. As in the case of most musculoskeletal injuries, acute dysfunction should be treated promptly to avoid the development of chronic pain. The complications of chronic pain include significant morbidity and mortality to the patient as well as the development of opioid dependence. A lack of prompt assessment of assessment and workup of sacroiliitis can lead to significant systemic injuries.

Consultations

Physicians who specialize in diagnosing and managing pain through a comprehensive understanding of the body's mechanics and musculoskeletal system are the following: Physical medicine and rehabilitation, sports medicine, pain management, and interventional spine physicians.

Deterrence and Patient Education

Part of the initial workup for acute back pain includes an assessment of the SI joint. SI joint pain is a common type of low back pain, and it is separate from the lumbar spine or paraspinal muscles often associated with low back pain. The spine and pelvis are connected posteriorly by the sacroiliac joint. The SI joint lies between the iliac bone and the sacrum. A common cause of SI joint injury includes trauma. Trauma can be repetitive, causing a series of small injuries that accumulate over time, such as in the case of an athlete, or can be significant trauma such as a pelvic fracture from a motor vehicle accident. Separately, SI joint injury is prevalent in pregnancy.

Furthermore, SI joint pain often occurs due to arthritis. Both degenerative osteoarthritis and inflammatory arthritis can lead to SI joint injury. Inflammatory arthritis of the SI joint is commonly known as sacroiliitis. When inflammatory changes are seen on imaging may be the sign of systemic disease. Imaging for SI joint dysfunction often includes an X-ray or MRI. Most cases of SI joint injury respond to conservative management, including physical therapy. However, some cases can require corticosteroid injections or even surgical repair.

Enhancing Healthcare Team Outcomes

Managing sacroiliac joint injury can be challenging. Low back pain secondary to SI joint dysfunction requires an interprofessional team of healthcare professionals that includes a primary care provider, physical therapist, primary care sports medicine specialist, pain medicine physician, radiologist, orthopedic surgeon, nurse specialist, and in cases of sacroiliitis, a rheumatologist. Without proper management, the morbidity associated with SI joint injury can become a chronic and debilitating injury. There are multiple steps involved in the injury assessment of the sacroiliac joint, the evaluation of the underlying injury, and treatment of sacroiliac injury:

• History and physical should be complete by the primary care provider, including special physical exam tests as well as initial x-ray imaging.
• Imaging to be interpreted by the radiologist. Standard imaging includes a weight-bearing AP view of the SI joint, MRI of the pelvis and sacrum, or CT of the pelvis.
• Initial therapy often provided by the primary care provider or orthopedist includes home exercise programs, over-the-counter pain medications, bracing, belts, manipulative therapy, and physical therapy.
• The physical therapist is crucial in the strengthening of the core muscles as well as the gluteus muscles, which are needed to help support the SI joint.
• Corticosteroid injection or anesthetic injections can be done either via ultrasound or fluoroscopy injections. A primary care sports medicine physician or pain medicine specialist is often utilized for this procedure.
• Refractory treatment such as radiofrequency ablation or rhizotomy can be complete with a pain medicine specialist as well.
• Suspected inflammatory SI Joint injury usually requires further assessment, including labs and management by a rheumatologist.
• Surgery can be necessary in refractory cases. Either an orthopedic surgeon specializing in spinal surgery or a neurosurgeon often performs the procedure. 
• Many cases of SI joint injury occur in athletes. A sports medicine specialist best manages long-term treatment and management of SI joint injuries.

The management of a sacroiliac joint injury can be both acute and chronic. Treatments range from conservative management to surgery. Diagnosis requires a high index of suspension in suspected cases. However, most cases improve conservatively. Many cases require the time and effort of multiple healthcare providers. [Level 5]

Review Questions

• Access free multiple choice questions on this topic.
• Click here for a simplified version.
• Comment on this article.

References

1.

Cohen SP, Chen Y, Neufeld NJ. Sacroiliac joint pain: a comprehensive review of epidemiology, diagnosis and treatment. Expert Rev Neurother. 2013 Jan;13(1):99-116. [PubMed: 23253394]

2.

van der Wurff P, Meyne W, Hagmeijer RH. Clinical tests of the sacroiliac joint. Man Ther. 2000 May;5(2):89-96. [PubMed: 10903584]

3.

Hansen H, Manchikanti L, Simopoulos TT, Christo PJ, Gupta S, Smith HS, Hameed H, Cohen SP. A systematic evaluation of the therapeutic effectiveness of sacroiliac joint interventions. Pain Physician. 2012 May-Jun;15(3):E247-78. [PubMed: 22622913]

4.

Schmidt GL, Bhandutia AK, Altman DT. Management of Sacroiliac Joint Pain. J Am Acad Orthop Surg. 2018 Sep 01;26(17):610-616. [PubMed: 30059395]

5.

Buchanan BK, Varacallo M. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 8, 2023. Sacroiliitis. [PubMed: 28846269]

6.

Bina RW, Hurlbert RJ. Sacroiliac Fusion: Another "Magic Bullet" Destined for Disrepute. Neurosurg Clin N Am. 2017 Jul;28(3):313-320. [PubMed: 28600005]

7.

Weiner DK, Sakamoto S, Perera S, Breuer P. Chronic low back pain in older adults: prevalence, reliability, and validity of physical examination findings. J Am Geriatr Soc. 2006 Jan;54(1):11-20. [PubMed: 16420193]

8.

Polsunas PJ, Sowa G, Fritz JM, Gentili A, Morone NE, Raja SN, Rodriguez E, Schmader K, Scholten JD, Weiner DK. Deconstructing Chronic Low Back Pain in the Older Adult-Step by Step Evidence and Expert-Based Recommendations for Evaluation and Treatment: Part X: Sacroiliac Joint Syndrome. Pain Med. 2016 Sep;17(9):1638-47. [PubMed: 27605679]

9.

Bjelland EK, Stuge B, Vangen S, Stray-Pedersen B, Eberhard-Gran M. Mode of delivery and persistence of pelvic girdle syndrome 6 months postpartum. Am J Obstet Gynecol. 2013 Apr;208(4):298.e1-7. [PubMed: 23220506]

10.

Coccolini F, Stahel PF, Montori G, Biffl W, Horer TM, Catena F, Kluger Y, Moore EE, Peitzman AB, Ivatury R, Coimbra R, Fraga GP, Pereira B, Rizoli S, Kirkpatrick A, Leppaniemi A, Manfredi R, Magnone S, Chiara O, Solaini L, Ceresoli M, Allievi N, Arvieux C, Velmahos G, Balogh Z, Naidoo N, Weber D, Abu-Zidan F, Sartelli M, Ansaloni L. Pelvic trauma: WSES classification and guidelines. World J Emerg Surg. 2017;12:5. [PMC free article: PMC5241998] [PubMed: 28115984]

11.

Albert HB, Godskesen M, Westergaard JG. Incidence of four syndromes of pregnancy-related pelvic joint pain. Spine (Phila Pa 1976). 2002 Dec 15;27(24):2831-4. [PubMed: 12486356]

12.

Smith MW, Marcus PS, Wurtz LD. Orthopedic issues in pregnancy. Obstet Gynecol Surv. 2008 Feb;63(2):103-11. [PubMed: 18199383]

13.

Robinson HS, Mengshoel AM, Bjelland EK, Vøllestad NK. Pelvic girdle pain, clinical tests and disability in late pregnancy. Man Ther. 2010 Jun;15(3):280-5. [PubMed: 20117040]

14.

Snow RE, Neubert AG. Peripartum pubic symphysis separation: a case series and review of the literature. Obstet Gynecol Surv. 1997 Jul;52(7):438-43. [PubMed: 9219278]

15.

Bjelland EK, Eskild A, Johansen R, Eberhard-Gran M. Pelvic girdle pain in pregnancy: the impact of parity. Am J Obstet Gynecol. 2010 Aug;203(2):146.e1-6. [PubMed: 20510180]

16.

Bjelland EK, Eberhard-Gran M, Nielsen CS, Eskild A. Age at menarche and pelvic girdle syndrome in pregnancy: a population study of 74 973 women. BJOG. 2011 Dec;118(13):1646-52. [PubMed: 21895953]

17.

Croisier JL. Factors associated with recurrent hamstring injuries. Sports Med. 2004;34(10):681-95. [PubMed: 15335244]

18.

Omar A, Sari I, Bedaiwi M, Salonen D, Haroon N, Inman RD. Analysis of dedicated sacroiliac views to improve reliability of conventional pelvic radiographs. Rheumatology (Oxford). 2017 Oct 01;56(10):1740-1745. [PubMed: 28957558]

19.

van den Berg R, Lenczner G, Feydy A, van der Heijde D, Reijnierse M, Saraux A, Rahmouni A, Dougados M, Claudepierre P. Agreement between clinical practice and trained central reading in reading of sacroiliac joints on plain pelvic radiographs. Results from the DESIR cohort. Arthritis Rheumatol. 2014 Sep;66(9):2403-11. [PubMed: 24909765]

20.

Dreyfuss P, Dryer S, Griffin J, Hoffman J, Walsh N. Positive sacroiliac screening tests in asymptomatic adults. Spine (Phila Pa 1976). 1994 May 15;19(10):1138-43. [PubMed: 8059269]

21.

Polly DW, Cher DJ, Wine KD, Whang PG, Frank CJ, Harvey CF, Lockstadt H, Glaser JA, Limoni RP, Sembrano JN., INSITE Study Group. Randomized Controlled Trial of Minimally Invasive Sacroiliac Joint Fusion Using Triangular Titanium Implants vs Nonsurgical Management for Sacroiliac Joint Dysfunction: 12-Month Outcomes. Neurosurgery. 2015 Nov;77(5):674-90; discussion 690-1. [PMC free article: PMC4605280] [PubMed: 26291338]

22.

Polly DW, Swofford J, Whang PG, Frank CJ, Glaser JA, Limoni RP, Cher DJ, Wine KD, Sembrano JN., INSITE Study Group. Two-Year Outcomes from a Randomized Controlled Trial of Minimally Invasive Sacroiliac Joint Fusion vs. Non-Surgical Management for Sacroiliac Joint Dysfunction. Int J Spine Surg. 2016;10:28. [PMC free article: PMC5027818] [PubMed: 27652199]

23.

Vleeming A, Albert HB, Ostgaard HC, Sturesson B, Stuge B. European guidelines for the diagnosis and treatment of pelvic girdle pain. Eur Spine J. 2008 Jun;17(6):794-819. [PMC free article: PMC2518998] [PubMed: 18259783]

24.

Protopopov M, Poddubnyy D. Radiographic progression in non-radiographic axial spondyloarthritis. Expert Rev Clin Immunol. 2018 Jun;14(6):525-533. [PubMed: 29774755]

25.

Ziade NR. HLA B27 antigen in Middle Eastern and Arab countries: systematic review of the strength of association with axial spondyloarthritis and methodological gaps. BMC Musculoskelet Disord. 2017 Jun 29;18(1):280. [PMC free article: PMC5492927] [PubMed: 28662723]

26.

Thawrani DP, Agabegi SS, Asghar F. Diagnosing Sacroiliac Joint Pain. J Am Acad Orthop Surg. 2019 Feb 01;27(3):85-93. [PubMed: 30278010]

27.

Fitzgerald CM, Neville CE, Mallinson T, Badillo SA, Hynes CK, Tu FF. Pelvic floor muscle examination in female chronic pelvic pain. J Reprod Med. 2011 Mar-Apr;56(3-4):117-22. [PubMed: 21542528]

28.

Potter NA, Rothstein JM. Intertester reliability for selected clinical tests of the sacroiliac joint. Phys Ther. 1985 Nov;65(11):1671-5. [PubMed: 2932746]

29.

Slipman CW, Sterenfeld EB, Chou LH, Herzog R, Vresilovic E. The predictive value of provocative sacroiliac joint stress maneuvers in the diagnosis of sacroiliac joint syndrome. Arch Phys Med Rehabil. 1998 Mar;79(3):288-92. [PubMed: 9523780]

30.

Levangie PK. Four clinical tests of sacroiliac joint dysfunction: the association of test results with innominate torsion among patients with and without low back pain. Phys Ther. 1999 Nov;79(11):1043-57. [PubMed: 10534797]

31.

Laslett M. Evidence-based diagnosis and treatment of the painful sacroiliac joint. J Man Manip Ther. 2008;16(3):142-52. [PMC free article: PMC2582421] [PubMed: 19119403]

32.

Rashbaum RF, Ohnmeiss DD, Lindley EM, Kitchel SH, Patel VV. Sacroiliac Joint Pain and Its Treatment. Clin Spine Surg. 2016 Mar;29(2):42-8. [PubMed: 26889985]

33.

Miller R, Beck NA, Sampson NR, Zhu X, Flynn JM, Drummond D. Imaging modalities for low back pain in children: a review of spondyloysis and undiagnosed mechanical back pain. J Pediatr Orthop. 2013 Apr-May;33(3):282-8. [PubMed: 23482264]

34.

Rodriguez DP, Poussaint TY. Imaging of back pain in children. AJNR Am J Neuroradiol. 2010 May;31(5):787-802. [PMC free article: PMC7964168] [PubMed: 19926701]

35.

Diekhoff T, Hermann KG, Greese J, Schwenke C, Poddubnyy D, Hamm B, Sieper J. Comparison of MRI with radiography for detecting structural lesions of the sacroiliac joint using CT as standard of reference: results from the SIMACT study. Ann Rheum Dis. 2017 Sep;76(9):1502-1508. [PubMed: 28283515]

36.

van Tubergen A, Heuft-Dorenbosch L, Schulpen G, Landewé R, Wijers R, van der Heijde D, van Engelshoven J, van der Linden S. Radiographic assessment of sacroiliitis by radiologists and rheumatologists: does training improve quality? Ann Rheum Dis. 2003 Jun;62(6):519-25. [PMC free article: PMC1754576] [PubMed: 12759287]

37.

Jang JH, Ward MM, Rucker AN, Reveille JD, Davis JC, Weisman MH, Learch TJ. Ankylosing spondylitis: patterns of radiographic involvement--a re-examination of accepted principles in a cohort of 769 patients. Radiology. 2011 Jan;258(1):192-8. [PMC free article: PMC3009382] [PubMed: 20971774]

38.

Poddubnyy D, Brandt H, Vahldiek J, Spiller I, Song IH, Rudwaleit M, Sieper J. The frequency of non-radiographic axial spondyloarthritis in relation to symptom duration in patients referred because of chronic back pain: results from the Berlin early spondyloarthritis clinic. Ann Rheum Dis. 2012 Dec;71(12):1998-2001. [PubMed: 22915622]

39.

Khmelinskii N, Regel A, Baraliakos X. The Role of Imaging in Diagnosing Axial Spondyloarthritis. Front Med (Lausanne). 2018;5:106. [PMC free article: PMC5913283] [PubMed: 29719835]

40.

Weber U, Jurik AG, Lambert RG, Maksymowych WP. Imaging in Spondyloarthritis: Controversies in Recognition of Early Disease. Curr Rheumatol Rep. 2016 Sep;18(9):58. [PubMed: 27435070]

41.

Lambert RG, Bakker PA, van der Heijde D, Weber U, Rudwaleit M, Hermann KG, Sieper J, Baraliakos X, Bennett A, Braun J, Burgos-Vargas R, Dougados M, Pedersen SJ, Jurik AG, Maksymowych WP, Marzo-Ortega H, Østergaard M, Poddubnyy D, Reijnierse M, van den Bosch F, van der Horst-Bruinsma I, Landewé R. Defining active sacroiliitis on MRI for classification of axial spondyloarthritis: update by the ASAS MRI working group. Ann Rheum Dis. 2016 Nov;75(11):1958-1963. [PubMed: 26768408]

42.

Marzo-Ortega H, McGonagle D, O'Connor P, Hensor EM, Bennett AN, Green MJ, Emery P. Baseline and 1-year magnetic resonance imaging of the sacroiliac joint and lumbar spine in very early inflammatory back pain. Relationship between symptoms, HLA-B27 and disease extent and persistence. Ann Rheum Dis. 2009 Nov;68(11):1721-7. [PubMed: 19019894]

43.

Weber U, Lambert RG, Østergaard M, Hodler J, Pedersen SJ, Maksymowych WP. The diagnostic utility of magnetic resonance imaging in spondylarthritis: an international multicenter evaluation of one hundred eighty-seven subjects. Arthritis Rheum. 2010 Oct;62(10):3048-58. [PubMed: 20496416]

44.

Arnbak B, Grethe Jurik A, Hørslev-Petersen K, Hendricks O, Hermansen LT, Loft AG, Østergaard M, Pedersen SJ, Zejden A, Egund N, Holst R, Manniche C, Jensen TS. Associations Between Spondyloarthritis Features and Magnetic Resonance Imaging Findings: A Cross-Sectional Analysis of 1,020 Patients With Persistent Low Back Pain. Arthritis Rheumatol. 2016 Apr;68(4):892-900. [PubMed: 26681230]

45.

de Hooge M, van den Berg R, Navarro-Compán V, Reijnierse M, van Gaalen F, Fagerli K, Landewé R, van Oosterhout M, Ramonda R, Huizinga T, van der Heijde D. Patients with chronic back pain of short duration from the SPACE cohort: which MRI structural lesions in the sacroiliac joints and inflammatory and structural lesions in the spine are most specific for axial spondyloarthritis? Ann Rheum Dis. 2016 Jul;75(7):1308-14. [PubMed: 26286018]

46.

Weber U, Pedersen SJ, Østergaard M, Rufibach K, Lambert RG, Maksymowych WP. Can erosions on MRI of the sacroiliac joints be reliably detected in patients with ankylosing spondylitis? - A cross-sectional study. Arthritis Res Ther. 2012 May 24;14(3):R124. [PMC free article: PMC3446505] [PubMed: 22626458]

47.

Mandl P, Navarro-Compán V, Terslev L, Aegerter P, van der Heijde D, D'Agostino MA, Baraliakos X, Pedersen SJ, Jurik AG, Naredo E, Schueller-Weidekamm C, Weber U, Wick MC, Bakker PA, Filippucci E, Conaghan PG, Rudwaleit M, Schett G, Sieper J, Tarp S, Marzo-Ortega H, Østergaard M., European League Against Rheumatism (EULAR). EULAR recommendations for the use of imaging in the diagnosis and management of spondyloarthritis in clinical practice. Ann Rheum Dis. 2015 Jul;74(7):1327-39. [PubMed: 25837448]

48.

Young S, Aprill C, Laslett M. Correlation of clinical examination characteristics with three sources of chronic low back pain. Spine J. 2003 Nov-Dec;3(6):460-5. [PubMed: 14609690]

49.

Rupert MP, Lee M, Manchikanti L, Datta S, Cohen SP. Evaluation of sacroiliac joint interventions: a systematic appraisal of the literature. Pain Physician. 2009 Mar-Apr;12(2):399-418. [PubMed: 19305487]

50.

Mens JM, Damen L, Snijders CJ, Stam HJ. The mechanical effect of a pelvic belt in patients with pregnancy-related pelvic pain. Clin Biomech (Bristol, Avon). 2006 Feb;21(2):122-7. [PubMed: 16214275]

51.

Ostgaard HC, Zetherström G, Roos-Hansson E, Svanberg B. Reduction of back and posterior pelvic pain in pregnancy. Spine (Phila Pa 1976). 1994 Apr 15;19(8):894-900. [PubMed: 8009346]

52.

Cibulka MT, Rose SJ, Delitto A, Sinacore DR. Hamstring muscle strain treated by mobilizing the sacroiliac joint. Phys Ther. 1986 Aug;66(8):1220-3. [PubMed: 3737692]

53.

Askling C, Karlsson J, Thorstensson A. Hamstring injury occurrence in elite soccer players after preseason strength training with eccentric overload. Scand J Med Sci Sports. 2003 Aug;13(4):244-50. [PubMed: 12859607]

54.

Engebretsen AH, Myklebust G, Holme I, Engebretsen L, Bahr R. Prevention of injuries among male soccer players: a prospective, randomized intervention study targeting players with previous injuries or reduced function. Am J Sports Med. 2008 Jun;36(6):1052-60. [PubMed: 18390492]

55.

van Mechelen W, Hlobil H, Kemper HC, Voorn WJ, de Jongh HR. Prevention of running injuries by warm-up, cool-down, and stretching exercises. Am J Sports Med. 1993 Sep-Oct;21(5):711-9. [PubMed: 8238713]

56.

Emery CA, Rose MS, McAllister JR, Meeuwisse WH. A prevention strategy to reduce the incidence of injury in high school basketball: a cluster randomized controlled trial. Clin J Sport Med. 2007 Jan;17(1):17-24. [PubMed: 17304001]

57.

Luukkainen RK, Wennerstrand PV, Kautiainen HH, Sanila MT, Asikainen EL. Efficacy of periarticular corticosteroid treatment of the sacroiliac joint in non-spondylarthropathic patients with chronic low back pain in the region of the sacroiliac joint. Clin Exp Rheumatol. 2002 Jan-Feb;20(1):52-4. [PubMed: 11892709]

58.

Irwin RW, Watson T, Minick RP, Ambrosius WT. Age, body mass index, and gender differences in sacroiliac joint pathology. Am J Phys Med Rehabil. 2007 Jan;86(1):37-44. [PubMed: 17304687]

59.

Maas ET, Ostelo RW, Niemisto L, Jousimaa J, Hurri H, Malmivaara A, van Tulder MW. Radiofrequency denervation for chronic low back pain. Cochrane Database Syst Rev. 2015 Oct 23;2015(10):CD008572. [PMC free article: PMC8782593] [PubMed: 26495910]

60.

Cohen SP, Hurley RW, Buckenmaier CC, Kurihara C, Morlando B, Dragovich A. Randomized placebo-controlled study evaluating lateral branch radiofrequency denervation for sacroiliac joint pain. Anesthesiology. 2008 Aug;109(2):279-88. [PMC free article: PMC2666931] [PubMed: 18648237]

61.

Cohen SP, Williams KA, Kurihara C, Nguyen C, Shields C, Kim P, Griffith SR, Larkin TM, Crooks M, Williams N, Morlando B, Strassels SA. Multicenter, randomized, comparative cost-effectiveness study comparing 0, 1, and 2 diagnostic medial branch (facet joint nerve) block treatment paradigms before lumbar facet radiofrequency denervation. Anesthesiology. 2010 Aug;113(2):395-405. [PubMed: 20613471]

62.

Juch JNS, Maas ET, Ostelo RWJG, Groeneweg JG, Kallewaard JW, Koes BW, Verhagen AP, van Dongen JM, Huygen FJPM, van Tulder MW. Effect of Radiofrequency Denervation on Pain Intensity Among Patients With Chronic Low Back Pain: The Mint Randomized Clinical Trials. JAMA. 2017 Jul 04;318(1):68-81. [PMC free article: PMC5541325] [PubMed: 28672319]

63.

Kocak O, Kocak AY, Sanal B, Kulan G. Bilateral Sacroiliitis Confirmed with Magnetic Resonance Imaging during Isotretinoin Treatment: Assessment of 11 Patients and a Review of the Literature. Acta Dermatovenerol Croat. 2017 Oct;25(3):228-233. [PubMed: 29252176]

64.

Pandita A, Madhuripan N, Hurtado RM, Dhamoon A. Back pain and oedematous Schmorl node: a diagnostic dilemma. BMJ Case Rep. 2017 May 22;2017 [PMC free article: PMC5753748] [PubMed: 28536227]

65.

Poddubnyy D, Listing J, Haibel H, Knüppel S, Rudwaleit M, Sieper J. Functional relevance of radiographic spinal progression in axial spondyloarthritis: results from the GErman SPondyloarthritis Inception Cohort. Rheumatology (Oxford). 2018 Apr 01;57(4):703-711. [PubMed: 29373733]

66.

Slobodin G, Hussein H, Rosner I, Eshed I. Sacroiliitis - early diagnosis is key. J Inflamm Res. 2018;11:339-344. [PMC free article: PMC6136407] [PubMed: 30237730]

67.

Chahal BS, Kwan ALC, Dhillon SS, Olubaniyi BO, Jhiangri GS, Neilson MM, Lambert RGW. Radiation Exposure to the Sacroiliac Joint From Low-Dose CT Compared With Radiography. AJR Am J Roentgenol. 2018 Nov;211(5):1058-1062. [PubMed: 30207791]

68.

Gutierrez M, Rodriguez S, Soto-Fajardo C, Santos-Moreno P, Sandoval H, Bertolazzi C, Pineda C. Ultrasound of sacroiliac joints in spondyloarthritis: a systematic review. Rheumatol Int. 2018 Oct;38(10):1791-1805. [PubMed: 30099591]

69.

Cusi M, Saunders J, Hungerford B, Wisbey-Roth T, Lucas P, Wilson S. The use of prolotherapy in the sacroiliac joint. Br J Sports Med. 2010 Feb;44(2):100-4. [PubMed: 18400878]

70.

Added MAN, de Freitas DG, Kasawara KT, Martin RL, Fukuda TY. STRENGTHENING THE GLUTEUS MAXIMUS IN SUBJECTS WITH SACROILIAC DYSFUNCTION. Int J Sports Phys Ther. 2018 Feb;13(1):114-120. [PMC free article: PMC5808006] [PubMed: 29484248]

71.

Miles D, Bishop M. Use of Manual Therapy for Posterior Pelvic Girdle Pain. PM R. 2019 Aug;11 Suppl 1:S93-S97. [PubMed: 31020812]

72.

Nelson AM, Nagpal G. Interventional Approaches to Low Back Pain. Clin Spine Surg. 2018 Jun;31(5):188-196. [PubMed: 28486278]

73.

Stuge B, Laerum E, Kirkesola G, Vøllestad N. The efficacy of a treatment program focusing on specific stabilizing exercises for pelvic girdle pain after pregnancy: a randomized controlled trial. Spine (Phila Pa 1976). 2004 Feb 15;29(4):351-9. [PubMed: 15094530]

74.

Whang PG, Darr E, Meyer SC, Kovalsky D, Frank C, Lockstadt H, Limoni R, Redmond AJ, Ploska P, Oh M, Chowdhary A, Cher D, Hillen T. Long-Term Prospective Clinical And Radiographic Outcomes After Minimally Invasive Lateral Transiliac Sacroiliac Joint Fusion Using Triangular Titanium Implants. Med Devices (Auckl). 2019;12:411-422. [PMC free article: PMC6769032] [PubMed: 31576181]

75.

van Lunteren M, Ez-Zaitouni Z, de Koning A, Dagfinrud H, Ramonda R, Jacobsson L, Landewé R, van der Heijde D, van Gaalen FA. In Early Axial Spondyloarthritis, Increasing Disease Activity Is Associated with Worsening of Health-related Quality of Life over Time. J Rheumatol. 2018 Jun;45(6):779-784. [PubMed: 29545448]

Disclosure: Alexander Dydyk declares no relevant financial relationships with ineligible companies.

Disclosure: Stephen Forro declares no relevant financial relationships with ineligible companies.

Disclosure: Andrew Hanna declares no relevant financial relationships with ineligible companies.