History
The key element in the diagnosis of sacroiliac dysfunction is pain. Many authors have attempted to define a typical pain pattern associated with the SIJ. Several of these reports describe patients reporting pain in one or both buttocks at or near the posterior superior iliac spine (PSIS). However, pain radiating to the hip, posterior thigh, or even calf has been described. [10]
Patients often relate that pain especially worsens when they have been sitting for long periods or when they perform twisting or rotary motions.
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Pain quality: The pain is described as a dull ache or sharp, stabbing, or knifelike.
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Pain distribution: Reported distributions are the buttocks, back of the thigh, and upper back; it can be unilateral or bilateral.
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History: Importantly, exclude a history of inflammatory disorders (eg, inflammatory bowel disease, Reiter syndrome).
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Fevers, weight loss, and pain in the night with night sweats: These are potential red flags for a systemic illness.
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Pain that is worse in the morning (morning stiffness) and resolves with exercise: This pattern is consistent with an inflammatory disease.
Physical
The reliability of the physical examination findings to diagnose SIJ dysfunction has been addressed in several articles. The usual pattern of examination is discussed, as follows:
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Inspection often reveals a pelvis with asymmetric height. This finding can be an indication of unilateral restriction in motion of one or both SIJs. Standing flexion testing involves the comparison of the symmetry of motion between the PSIS on the tested side and the S2 spinous process (Gillet test). However, Freburger and Riddle questioned the reliability of examinations between testers. [11]
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Of paramount importance is to measure the limb lengths to look for inequality, inspect the lumbar spine to look for scoliosis, and rotate the hips to look for motion restriction.
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Palpation may be the most reliable indication of SIJ pain. The patient usually places a thumb directly onto one particular spot in the dimple of the PSIS (sacral sulcus). The patient can usually precisely reproduce the pain over that one spot (Fortin finger sign). [9] More diffuse back or buttock and leg pain should prompt the clinician to question the diagnosis of SIJ dysfunction (see Differentials and Other Problems to Be Considered).
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Upon neurologic examination, motor strength, sensory examination, and reflexes in the lower extremities should all prove normal. However, sometimes, strength examination proves challenging, and the patient may exhibit weaknesses because of pain inhibition or frank muscle imbalance that developed during episodes of pain and relative inactivity. True neurogenic weakness, numbness, or loss of reflex should alert the clinician to consider nerve root injury or pathology other than a mechanical dysfunction.
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Perform pain provocation tests. [9, 12, 13, 14, 15] Distraction can be performed to the anterior sacroiliac ligaments by applying pressure to the anterior superior iliac spine (iliac gapping test). Apply compression to the joint with the patient lying on his or her side. Pressure is applied downward to the uppermost iliac crest (iliac compression test).
The goal of the Gaenslen test is to apply torsion to the joint. With one hip flexed onto the abdomen, the other leg is allowed to dangle off the edge of the table. Pressure should then be directed downward on the leg in order to achieve hip extension and stress the SIJ.
For the flexion, abduction, and external rotation (FABER or Patrick) test, the examiner externally rotates the hip while the patient lies supine. Then, downward pressure is applied to the knee.
In all tests, pain in the typical area raises suspicion for an SIJ lesion.
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Unfortunately, although systematic, these tests have not proven reliable in controlled studies. Dreyfuss and colleagues studied 12 SIJ tests in relation to fluoroscopically guided SIJ injection. [16] They were unable to find even one of these tests to be highly sensitive or specific for diagnosing SIJ pain. Hancock et al also published a review on physical examination testing reliability to diagnose SIH syndrome. [13]
Stuber conducted a systematic review of the literature to determine the specificity, sensitivity, and predictive values of such clinical tests of the sacroiliac joint. [12] According to the author, "the search was conducted using several online databases: Medline, Embase, Cinahl, AMED, and the Index to Chiropractic Literature. Reference and journal searching and contact with several experts in the area was also employed."
Stuber concluded that the distraction test, compression test, thigh thrust/posterior shear, sacral thrust, and resisted hip abduction were the only tests to have specificity and sensitivity greater than 60% in at least one study, and that further investigation is warranted to determine which tests or combinations of these tests are the best for diagnosing SIJ dysfunction.
Causes
Many patients state that their pain began spontaneously, whereas others can cite a specific inciting event. Bernard and Kirkaldy-Willis reported that 58% of patients diagnosed with SIJ pain based on clinical examination findings had some inciting traumatic injury. [3]
Many risk factors are associated with lower back pain, and many are directly associated with lumbar disk injury. These include, but are not limited to, smoking, poor physical condition, positive family history, and occupational lifting.
Factors that specifically increase the likelihood of mechanical injury to the SIJ have not been identified. Pregnancy is one particular condition attributed to SIJ dysfunction.
In the authors’ experience, certain biomechanical or muscle length imbalances may ultimately predispose a person to sacroiliac dysfunction and pain. Likely, this is a result of altered gait patterns and repetitive stress to the SIJ and related structures. These conditions exist in persons with leg-length inequality, scoliosis, a history of polio, poor-quality footwear, and hip osteoarthritis.
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Flouroscopically guided sacroiliac joint injection. Contrast seen throughout the joint.
