Sacroiliitis

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Definition/Description

Sacroiliitis is an inflammation of the sacroiliac joint (SI), usually resulting in pain. The sacroiliac joint (SI) is one of the largest joints in the body and is a common source of the buttock and lower back pain. It connects the bones of the ilium to the sacrum.

Sacroiliitis

• Often it is a diagnosis of exclusion.
• Can be particularly difficult to diagnose because its symptoms are similar to many other common sources of back pain.
• Often is overlooked as a source of back or buttock pain.
• Pain from this condition often is due to chronic degenerative causes yet relatively uncommon.
• Can be secondary to rheumatic, infectious, drug-related, or oncologic sources.

Some specific examples of non-degenerative conditions that can lead to sacroiliitis are ankylosing spondylitis, psoriatic arthropathy, Behcet's disease, hyperparathyroidism, and various pyogenic sources.

Clinically Relevant Anatomy

The sacrum articulates with the ilium, which helps to distribute body weight to the pelvis.

The SI joint capsule is relatively thin and often develops defects that enable fluid, such as joint effusion or pus, to leak out onto the surrounding structures.

The Sacroiliac Joint

• True diarthrodial joint, the articular surfaces are separated by a joint space containing synovial fluid and enveloped by a fibrous capsule.
• Has unique characteristics not typically found in other diarthrodial joints.
• Consists of fibrocartilage in addition to hyaline cartilage and is characterized by discontinuity of the posterior capsule, with ridges and depressions that minimize movement and enhance stability.
• Well provided with nociceptor and proprioceptors. Receives its innervation from the ventral rami of L4 and L5, the superior gluteal nerve, and the dorsal rami of L5, S1 and S2 or that it is almost exclusively derived from the sacral dorsal rami^.

Etiology

Various conditions result in the inflammation of the SI joint, leading to significant pain.

• Osteoarthritis can cause degeneration of the joint resulting in pathologic articulation and motion leading to this condition.
• Spondyloarthropathies can cause significant inflammation of the joint itself eg Ankylosing spondylitis, reactive arthritis, psoriatic arthritis, arthritis of chronic inflammatory bowel disease
• Pregnancy is another cause of the inflammation due to the hormone relaxin leading to the relaxation, stretching, and possible widening of the SI joint(s). The increased weight of pregnancy also causes extra mechanical stress on the joint, leading to further wear and tear.
• Trauma can cause direct or indirect stress and damage to the SI joint.
• Pyogenic sacroiliitis is the most frequently reported cause of acute sacroiliitis.
• Pain can originate from the synovial joint but can also originate from the posterior sacral ligaments

Epidemiology

Reports on the prevalence of sacroiliac pain vary widely.

• Some studies report the prevalence as 10% to 25% of those with lower back pain.
• In those with a confirmed diagnosis, the presentation of pain was ipsilateral buttock (94% cases) and midline lower lumbar area (74%).
• Up to 50% of cases have radiation to the lower extremity: 6% to the upper lumbar area, 4% percent to the groin, and 2% percent to the lower abdomen
• Symmetrical sacroiliitis is found in more than 90% of ankylosing spondylitis and 2/3 in reactive arthritis and psoriatic arthritis.
• It is less severe and more likely to be unilateral and asymmetrical in reactive arthritis, psoriatic arthritis, arthritis of chronic inflammatory bowel disease and undifferentiated spondyloarthropathy. 
• The hospital prevalence of sacroiliac diseases is 0,55%, the female sex predominates( 82,35%) and the mean age of 25,58 years. Gyneco-obstetric events are the predominant risk factors (47,05%). The etiologie found are bacterial arthritis (82,3%) mainly pyogenic (70,58%), osteoarthritis(11,7%) and ankylosing spondylitis (5,9%) .

Characteristics/Clinical Presentation

Sacroiliitis commonly presents as lower back pain.

Patients may report

• Pain in one or both buttocks, hip pain, thigh pain, or even pain more distal.
• Pain is worse after sitting for prolonged periods or with rotational movements.
• Intolerance with lying or sitting and increasing pain while climbing stairs or hills.
• Poor sleep habits and unilateral giving way or buckling.
• Pain with position changes or transitional motions (i.e., sit to stand, supine to sit). 
• Pain (varies widely) and is commonly described as sharp and stabbing but can also be described as dull and achy.

Important to ascertain more than just the timing and descriptions of the pain. Ask about a history of inflammatory disorders.

• Obtain a thorough review of systems to evaluate for systemic symptoms such as fevers, chills, night sweats, and weight loss. These symptoms are indicative of a more serious process indicating likely systemic illness.Patients report low back pain (below L5), pain in the buttocks and/or pelvis and postero-lateral on the thigh, which may extend down to one or both legs.

Differential Diagnosis

The diagnosis of acute sacroiliitis is often challenging because of both the relative rarity of this presentation and diverse character of acute sacroiliac pain, frequently mimicking other, more prevalent disorders.

New-onset intense pain is a major clinical manifestation of acute sacroiliitis, pointing to the diagnosis. The diagnosis of acute sacroiliitis is frequently overlooked at presentation.   

• Ankylosing spondylitis
• Hip tendonitis/fracture
• Piriformis syndrome
• Sacroiliac joint infection
• Trochanteric bursitis

Diagnostic Procedures

Radiographic features

Plain radiograph

Conventional radiography remains the first line of imaging despite its poor sensitivity and specificity in early disease. Specific sacroiliac joint views are helpful in the evaluation and comparing both sides of sacroiliac joints.

Radiograph findings include:

sclerosis of the endplates particularly on the iliac side

irregular joint end plates

widening of joint spaces

CT

CT examinations offer greater sensitivity, accuracy and detailed information compared to plain radiography. However, due to higher radiation exposure, it is not advisable to use CT for diagnosis or follow-up purposes.

Nuclear medicine

Bone scans demonstrate increased radioisotope activity of the joints and helpful in localising the source of the pain. It is also valuable in excluding stress fractures and other bone pathologies.

The diagnosis of sacroiliitis in clinical practice is based mainly on imaging techniques. It can be difficult to diagnose sacroiliitis in the early and acute stages because conventional radiographs may be normal, although other techniques, to be discussed, might detect sacroiliac inflammation. The radiographic images of the sacroiliac joint changes in advanced disease, sclerosis and may cause erosions. However, this might no longer be visible on the radiograph because of ankylosis.

Inflammatory back pain (IBP) can be a result of sacroiliitis. Because IBP is not a highly specific indicator of sacroiliitis, there is a need for valuable imaging techniques.

Techniques currently used to diagnose sacroiliitis:

• Radiography
• Scintigraphy
• Conventional tomography
• Computed tomography
• Magnetic resonance imaging

Scintigraphy lacks specificity. Computed tomography (CT) is a very good method to demonstrate already established bony changes and magnetic resonance imaging (MRI) has the ability to localize edema and differentiate degrees of inflammation. The MRI gives a good visualization of the complex anatomy of the sacroiliac joint. This testing can prove a possible spread to muscles as it occurs in septic sacroiliitis, an important differential diagnosis.

Devauchelle-Pensec et al compared computed tomography scanning and radiographs for the diagnosis of sacroiliitis. The conclusion of this study was that definite sacroiliitis was underestimated by radiography, as compared to CT scanning.

^{Blum et al determined the specificity and sensitivity for the diagnosis of active sacroiliitis, for each imaging method (plain radiography, scintigraphy, and contrast enhanced MRI). They used a reference standard, based on the clinical symptoms of inflammatory low back pain with or without laboratory signs, and clinical and radiographic findings. They performed a follow up during 1.5-2.5 years to confirm diagnosis. According to the results, MRI was most sensitive for the detection and confirmation of active sacroiliitis (95%) and superior to quantitative SI scintigraphy (48%) or conventional radiography (19%). MRI also had a higher specificity (100%) than scintigraphy (97%) or plain radiography (47%) for the assessment of inflammatory signs. There were persistent pathological signal intensities in the subchondral bone area despite clinically successful anti-inflammatory drug therapy, at repeat MRI testing after 2-30 months. It’s also possible to differentiate the diagnosis between infection and spondyloarthritis using the MRI features of bone lesions, soft-tissue lesions and joint space enhancement in unilateral sacroiliitis. Among various findings, periarticular muscle edema was the single most important predictor of infectious sacroiliitis.}

Sacroiliitis of seronegative spondyloarthropathy may sometimes show on pelvis plain films findings indistinguishable from those of osteitis condensans ilii. Computed tomography (CT) can differentiate earlier than plain radiography. There are criteria proposed by the European Spondlylarthropathy Study Group (EESG) that you can use to differentiate the two conditions. There is proof that the criteria are useful. It is right to differentiate clinically between the two diseases.

Outcome Measures

Outcome measures such as the Oswestry Disability Index (ODI) is most effective for persistent, severe disability, while the Roland-Morris is more appropriate for mild to moderate disability. ^{The Short-form McGill Pain Questionnaire (link) and The Assessment of Pain and Occupational Performance may also be appropriate.}

Examination

Some individual pain provocation tests show sufficient inter-rater reliability. The following tests seem to have sufficient diagnostic accuracy:(Patrick-) FABER = Flexion, ABduction, External Rotation test , thigh thrust test*, Gaenslen test, Mennell’s test**, sacral thrust test***, compression test**** and distraction test.   

Combinations of these tests give a better accuracy to differentiate sacroiliitis from low back pain. We can use a combination of 3 tests (ex. Gaenslen, Mennell, and thigh thrust tests) or 5 tests (ex. Gaenslen, Patrick-Faber, Mennell, thigh thrust, and sacral thrust tests), which give favorable results respectively, if 2 or 4 tests are positive. A positive test means it provokes pain.  

A complete physical examination with an excellent accuracy to diagnose sacroiliac joint related pain should involve a cluster of sacroiliac joint tests and a McKenzie evaluation.   MRI and CT are also uses in the early stage to diagnose sacroiliitis.

Thigh thrust test*:
Subject: Supine, contralateral leg extended
Examiner: Stands next to the subject
Technique: The examiner flexes the affected leg (contralateral), approximately hip at 90°, knees remain relaxed and graded force pressure is applied through the long axis of the femur (=posterior shearing stress), one hand underneath the sacrum, the other one around the knee to give pressure

Mennell’s test**:
Subject: Side-lying position, affected side is down, back towards the edge of the table. Affected (table contacting) side hip flexed to the abdomen, knee is flexed
Examiner: Stands behind the patient
Technique: Examiner puts one hand over the ipsilateral gluteal region and iliac crest, other hand grasps the semi flexed ipsilateral knee and lightly forces the leg to extension

Sacral thrust test***:
Subject: Prone, legs relaxed, semi abducted
Examiner: Stands behind the subject, close to the feet at the lower edge of the table
Technique: Puts hands over the sacrum applies anterior pressure to the sacrum

Compression test****:
Subject: Compression Side-lying position, affected side is up, close to the side of the table and back towards the edge of the table. Hips
flexed approximately 45°, knees are flexed approximately 90° degrees
Examiner: Stands behind the subject
Technique: Examiner’s Folded hands over the anterior edge of the iliac crest and applies downward pressure

Distraction test:
The SIJ (Sacroiliac joint) Distraction (Colloquially know as Gapping) test is used to add evidence, positive or negative, to the hypotheses of an SIJ sprain or dysfunction when used in the Laslett SIJ Cluster testing. This test stresses the anterior sacroiliac ligaments  This test has also been described as the Transverse Anterior Stress Test or the Sacroiliac Joint Stress Test.

1. The patient lies supine and the examiner applies a vertically orientated, posteriorly directed force to both the anterior superior ilac spines (ASIS) (Cook and Hegedus 2013, Laslett et al 2008, Laslett et al 2005, Laslett et al 2003). Note: Cook and Hegedus (2013) suggest applying a sustained force for 30 seconds before applying a repeated vigorous force in an attempt to reproduced the patient’s symptoms. However, Laslett (2008) does not suggest any timings or changes in force.
   Because of the lack of standardisation in the technique it is quite feasible different therapists will practise this test different ways, giving rise to variability in response and lowering the inter-tester reliability (Laslett et al 2005, Levin et al 2005). No evidence to suggest either method is preferable (Levin et al 2005), therefore, more evidence needed.
2. The presumed effect is a DISTRACTION of the anterior aspect of the sacroiliac joint. (Laslett et al 2005, Laslett et al 2003)
3. A test is positive if it reproduces the patient's symptoms. This indicates SIJ dysfunction or a sprain of the anterior sacroiliac ligaments (Cook and Hegedus 2013, Cook et al 2007, Laslett 2008, Laslett et al 2005, Laslett et al 2003) However, this test should be used in concordance within a SIJ testing cluster to ensure maximum reliability and validity when confirming hypotheses (Albert et al 2000, Kokmeyer et al 2002, Laslett 2008, Laslett et al 2005,Laslett et al 2003, Ozgocmen et al 2008, Robinson et al 2007). 

The sacroiliac joint can be examined by Special tests.

Medical Management

Reducing inflammation in the SI-joint and increasing the flexibility of the lumbosacral spine and SI areas are the main goals of treatment. NSAIDs (non-steroidal anti-inflammatory drugs) and anti-rheumatic drugs are the primary treatment for spondyloarthropathy. Global pain decreased significantly following treatment with naproxen (NSAID). Sulfasalazine is believed to reduce the erythrocyte sedimentation rate and morning stiffness.  Research revealed that a continuous treatment with NSAID’s reduces radiographic progression in symptomatic patients with AS.  

The patient must be referred to a physiotherapist. Suggest 3 to 4 days bed rest for severe acute cases. For persistent cases (2 to 4 weeks) with severe pain, a sacroiliac joint injection may be recommended to confirm the sacroiliac joint as the source of the pain and to introduce the anti-inflammatory medication directly into the joint. Advise 3 to 4 days of bed rest after the injection. Next it is recommended to continue with the restrictions and begin with flexion strengthening exercises after the pain and inflammation have been controlled. These exercises include side-bends, knee chest pulls and pelvic rocks.

Therapeutic solutions include intra-atricular injections with short-term pain relief and surgical fusion, which appears ineffective. Radiofrequency of the joint capsule or lateral branches has been previously reported with variable successes. The majority of patients with chronic SI joint pain experienced a clinically relevant degree of pain relief and improved function following cooled radiofrequency of sacral lateral branches and dorsal ramus of L5 at 3-4 months follow-up.

If the condition persists (6 to 8 weeks) with no improvement of at least 50 percent, repeat corticosteroid injections. Subsequently begin strengthening exercises including sit-ups and weighted side bends. Start with general conditioning of the back and increase slowly to low-impact walking or swimming. Take up normal activities with proper care of the back.

Physical Therapy Management

Reducing inflammation in the SI-joint and increasing the flexibility of the lumbosacral spine and SI areas are the main goals of treatment. Give advice on proper lifting techniques involving the knees. The patient should also avoid movements such as tilting, twisting and extremes of bending. Maintaining correct posture is necessary, therefore a lumbar support for the office chair and vehicle is advised.

In the early treatment stages heat, cold or alternating cold with heat are effective in reducing pain.  ^{Cryotherapy can be used to control the inflammation and pain. This form of treatment can be applied by ice massage or the application of ice packs. Cryotherapy should be applied for no more than 20 minutes, with at least one hour between applications. Ice massages will usually require a shorter treatment time. Thermotherapy can also be used by applying hot packs for a maximum of 20 minutes. This form of therapy is used to control pain, increase circulation and to increase soft tissue extensibility. With the aim of reducing pain, conventional TENS (Transcutaneous electrical nerve stimulation) can also be applied.}

In the early stage, we can also use a pelvic belt or girdle during exercise and activities of daily living. These SI belts provide compression and reduce SI mobility in hypermobile patients. The belt should be positioned posteriorly across the sacral base and anteriorly below the superior anterior iliac spines. This belt may also be used when this condition becomes chronic (10-12 weeks).

Once the acute symptoms are under control, the patient can start with flexibility exercises and specific stabilizing exercises. To maintain SI and lower back flexibility, stretching exercises are principal. These exercises include side-bends, knee chest pulls, and pelvic-rocks with the aim of stretching the paraspinal muscles, the gluteus muscles and the SI joint. After hyperacute symptoms have resolved these kinds of exercises should be started. Each stretch is performed in sets of 20. These exercises should never surpass the patient’s level of mild discomfort.

Specific pelvic stabilizing exercises, postural education and training muscles of the trunk and lower extremities, can be useful in patients with sacroiliac joint dysfunctions. The transversus abdominis, lumbar multifidi muscles and pelvic floor are the muscles that will need most training. Training of transversus abdominis independently of other abdominal muscles is effective to provide more stabilization of the sacroiliac joints and prevent laxity, which can cause low back pain. Therefore it is necessary to teach the patient how to contract the transversus abdominis and multifidus. During this learning process it is necessary to give the patient feedback. Also the specific co-contraction of the transversus abdominus and the multifidus should be included in the revalidation program. The best position to teach the patient to co-contract these muscles is in four point kneeling. When the patient can properly perform this exercise, it is time to increase the intensity by changing the starting position,…

Other examples of exercises may include: modified sit-ups, weighted side-bends and gentle extension exercises.
Strengthening of the pelvic floor muscles is also important because they oppose lateral movements of the coxal bones, which stabilizes the position of the sacrum. Activation of the transversus abdominis and pelvic floor muscles will reduce the vertical sacroiliac joint shear forces and increase the stability of the sacroiliac joint.
After rehabilitation, low-impact aerobic exercises such as light jogging and water aerobics are designated to prevent recurrence.

If the patient has a leg length discrepancy or an altered gait mechanism, the most reliable treatment would be to correct the underlying defect. Sacroiliitis is also a feature of spondyloarthropathies. In this case, this condition should also be treated.

Presentations

Pelvic Physiotherapy - to Kegel or Not? This presentation was created by Carolyn Vandyken, a physiotherapist who specializes in the treatment of male and female pelvic dysfunction. She also provides education and mentorship to physiotherapists who are similarly interested in treating these dysfunctions. In the presentation, Carolyn reviews pelvic anatomy, the history of Kegel exercises and what the evidence tells us about when Kegels are and aren't appropriate for our patients. View the presentation