Introduction

The Sacroiliac Joints (SIJ) are auricular-shaped and lie between the sacrum and ilium, constituting the largest axial joint in the pelvis and facilitating the articulation iliac bones to the sacrum ¹,². Their anatomy allows for the exchange of load located in the lumber spine and lower limbs. The SIJ is around 1-2 mm in width, and each joint on either side of the sacrum is bound by a fibrous capsule. The iliac aspect of the sacroiliac joint (SIJ) has cartilage that is thinner than the sacral aspect, thicker cortical bone, and denser cacellous bone. Numerous ligaments and pelvic floor muscles, such as the levator ani and coccygeus muscles, support the SIJ Due to its anatomical and biophysical properties, the SIJ is crucial in preserving the mechanical stability of the human body. The joint's main biomechanical function is to transfer forces from the legs to the body. This function is crucial, especially during bipedal walking ^2,3Numerous ligaments and pelvic floor muscles, such as the levator ani and coccygeus muscles, support the SIJ. These elements aid in the transmission of shear forces by supporting the joint limiting its range of motion, and maintaining its stability of the joint¹. Women have more flexibility in their SIJ ligaments and have a center of gravity that is more forward on the body. In contrast, the male pelvis is wider than the female pelvis, particularly in the distance between the iliac crests ^2,3

The result of this load transmission is significant mechanical stress on the SIJ ². The mechanism of injury SIJ can be addressed as a mixture of axial loading and sudden rotation. Many alterations in the structure of SI joints can create a sensation of pain. These alterations include: small or large fractures, cartilage softening, soft tissue destruction, inflammation, disruption of the capsule or synovium, stress in the capsule and ligaments, restricted or excessive joint mobility, external compression, or shearing forces, and irregular joint function ⁴.

According to estimates, between 70% and 85 % of people in Western societies will suffer from lower back pain at some point in their lives¹. SIJ dysfunction is thought to be the root cause of lower back pain in up to 30 % of cases ³. The epidemiology of SIJ dysfunction is not well-known, but it is known that this pathology is common worldwide and disabling. According to Sembrano and Polly, 65 % of patients with Low Back Pain (LBP) had spine-only pathology, followed by 14.5 % of patients with SIJ dysfunction, 12.5 % with hip pathology, and the remaining 10 % with pain of unknown etiology². SIJ pain is often seen in young people who play sports and receive trauma or injuries. Additionally, elderly people can experience SIJ pain if they have degenerative joint disease, and pregnant women also complain of SIJ discomfort. Since women have heightened SIJ joint flexibility, more stress is placed on their mobility and the load on surrounding tissues, making them more prone to experiencing SIJ dysfunction ⁵.

Causes

SIJ dysfunction typically results from abnormal motion, including hyper or hypomobile Sacroiliac joints and malalignment ^2,6. This condition may develop due to various factors, such as limb length inequality (LLD), high-velocity trauma, previous lumbar fusion surgeries, injuries, degenerative arthritis, moderate impact exercise, overexertion, inflammatory bowel disease, spondyloarthropathies like ankylosing spondylitis, joint infections, abnormal gait patterns, and scoliosis^2,7. Dysfunction can also occur during atypical lifting, forward bending, or assuming a lordotic posture, causing a misalignment of the body's center relative to the acetabular center. Dysfunction is likely to arise if the abdominal muscles cannot adequately support rotation and force transmission ². Despite the underlying cause, the relationship between pain and SIJ dysfunction remains consistent ⁷.

Diagnosis

Specific physical examination tests, including the FABER, compression, distraction, thigh thrust, and Gaenslen tests, are used to diagnose SIJ dysfunction. A diagnosis of SIJ pain is typically made when three out of the five provocative tests return positive results, with at least one of these being the compression or thigh thrust test. However, a recent study, to diagnose SIJD in patients, this study compared motion palpation and pain provocation tests to the gold-standard sacroiliac joint block procedure ⁸.

The FABER test involves positioning the hip and knee, with a positive result indicated by pain on the side of the flexed knee. In the FABER test, also known as Patrick's test, the patient lies supine. One knee is flexed at a 90-degree angle, while the opposite knee is laid flat on the examination table. The examiner presses the contralateral Anterior Superior Iliac Spine (ASIS) against the table, and then pushes the bent knee down towards the table ⁸.

In the Gaenslen test, a posterior force is applied to the caudal knee, while the pelvis is mobilized by a superior or posterior force directed towards the cephalad knee.

In the Thigh Thrust Test, force is directed through the axis of the femur with the cephalad hand, creating a shear force. This is done simultaneously with the sacrum being stabilized against the table with the caudal hand.

Figure 1
Distraction Test

Figure 2
Thigh Thrust Test

Figure 3
Compression Test

Figure 4
FABER Test

Figure 5.1
Gaenslen Test. Lateral View

Figure 5.2
Gaenslen Test. Superior View

In the Distraction test, a posteriorly directed force is applied to the anterior superior iliac spine, distracting the sacroiliac joints.

In the Compression test, similar to the Distraction test, a posteriorly directed force is applied to the iliac crest, compressing the sacroiliac joint ⁹.

If performed correctly, one of the highest sensitivities among the five tests can come from the FABER test ¹⁰.

During the Thigh Thrust Test, compression of the SIJ resulting in pain indicates a successful result. A positive outcome of the Gaenslen test causes pain in the lower back, stressing both SIJ. Compression of the SIJ during the Compression Test, with resulting pain, indicates a successful result. The Distraction Test distinguishes between ASIS and SIJ pain based on a positive outcome.

Based on responses to pain, these tests assist in diagnosis SIJ dysfunction⁸. Diagnostic imaging such as magnetic resonance imaging (MRIS) and X-rays are also employed to achieve accurate diagnoses of SIJ. The diagnostic gold standard has shifted towards using intra-articular SIJ blocks, as there is no conclusive evidence that any specific provocative test or imaging technique definitively indicates SIJ pain. These involve the injection of local anesthetics as a diagnostic tool, sometimes supplemented with steroids¹.

Misdiagnosis

Despite the various methods available for diagnosing SIJ dysfunction, it remains commonly misdiagnosed due to symptom similarities with other conditions such as intervertebral discs and facet joints¹¹. Furthermore, since SIJ pain may coincide with non-neurological symptoms like dyspareunia and bladder dysfunction, it can be mistaken for issues unrelated to its underlying cause and attributed to other areas¹².

In a study by Song et al., a 33-year-old woman initially diagnosed with Ankylosing Spondylitis (AS) experienced chronic buttock pain and sacroiliitis progression, (detected using plain X-ray and an MRI). Treatment with nonsteroidal anti-inflammatory drugs (NSAIDS), for AS proved ineffective. Subsequent pelvic bone computed tomography (CT) revealed an Accessory Sacroiliac Joint (ASIJ) with degenerative alterations, sclerosis, and osteophytes in the right SI joint¹³.

In another study, Prassopoulos et al. utilized CT scans to analyze SIJ anatomical variations, identifying ASIJ as the most prevalent variant at 19 %¹⁴. Despite its prevalence, the clinical significance of ASIJ often overlooked, particularly because most cases are asymptomatic and incidentally diagnosed¹³.

For example, Demir et al., discovered ASIJ to be the most prevalent SIJ variant in their study, with 17.5 % of patients exhibiting it on a CT scan. Notably, many of these patients were asymptomatic for lower back pain¹⁵. Nevertheless, this absence of symptoms does not preclude the possibility of symptomatic presentation. ASIJ frequently manifest as chronic buttock pain and/or lower back pain, particularly among patients with severe arthritis and degenerative alterations.

In a study evaluating lower back pain in individuals under 40 years old using CT scans, ASIJ was identified as a source of pain in 4.5 % of cases. Additionally, 31 % showed abnormal SIJ examinations, 10.2 % were suspected to have sacroiliitis, and 3.3 % had confirmed sacroiliitis among 484 lumbar spine CT analysis ¹⁶.

Clinicians must maintain awareness of symptoms associated with SIJ dysfunction, and its specific variants. This awareness can aid in preventing misdiagnosis and ensuring appropriate treatment ¹⁰.

Treatments

The treatment options for SIJ dysfunction range from conservative management to surgical approaches. Conservative management includes physical therapy, oral painkillers like NSAIDS, medical therapy, and chiropractic care. Patients should receive education on lifestyle modifications and proper weightlifting, and outpatient physical therapy should be pursued after acute management ². If pelvic instability is identified as part of the SIJ pain etiology a sacroiliac belt may be used for a short period as additional support ²,¹⁷.

If conservative measures fail within 6 weeks, further interventions such as injections (intraarticular or periarticular), nerve blocks, and radiofrequency procedures may be considered². A diagosis SIJ joint injections serve both diagnostic and therapeutic purposes. A diagnostic SIJ block may be considered if a patient responds favorably to three or more of these tests, indicating a likelihood of SIJ problems. An anesthetic is injected into the SI joint during diagnostic blocks. Confirmation of SIJ dysfunction occurs if the patient experiences at least a 75 % reduction in pain while performing previously painful movements during the anesthetic ¹⁸.

Initial treatments for pain managing typically involve a combination of methods like pain control and physical therapy. However, there is a growing body of evidence supporting the use of minimally invasive procedures. These procedures can complement conservative approaches or secondary options for patients who do not respond to initial treatments.

In a study, it was found that after 12 months, pain scores improved by 2.7 points in the group using traditional open treatments and by 6.2 points in the group using minimally invasive procedures. For the 2-year assessment (available for 96 patients), there was an improvement of 2 points in the open treatment group and 5.6 points in the minimally invasive treatment group. Therefore, minimally invasive treatment options have also been considered effective in treating SIJ pain ¹⁹. They have also been shown to be more effective than conservative treatment.

Results comparing conservative vs. surgical procedures were examined in a study by Dengler et al. Fifty-one patients received conservative treatment, consisting of six months of physical therapy. Two participants received additional sacroiliac corticosteroid injections, and one received injections along with radiofrequency ablation. Fifty-two patients underwent minimally invasive sacroiliac arthrodesis with triangular titanium implants. When the results were analyzed, there was a significant improvement in lower back pain in the group that received invasive therapy at 6 and 24 months after treatment ²⁰.

Conclusion

SIJ dysfunction is a condition with increasing prevalence, often leading to misdiagnosis despite available diagnostic methods. Raising awareness of SIJ dysfunction among medical professionals and the public is crucial to ensure correct diagnosis and proper treatment. As research continues to elucidate SIJ dysfunction's etiology and methods for preventing misdiagnosis, comprehensive reviews become essential for refining clinical practices and enhancing patient health. By deepening understanding and improving diagnostic reliability and accuracy, efforts focused on SIJ dysfunction pave the way for refined neurological care and treatment effectiveness. Overall, these efforts benefit patients by ensuring that appropriate care is tailored to their specific condition.

References

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