In individuals with low back pain, sacroiliac joint (SIJ) is the most common pain causing joint (1). SIJ is developed by the junction between iliac bone and sacral bone. Association between two bones, muscles and ligaments provide the stability to the joint. This joint is the largest joint of body with a diameter of 17.5 cm² (2). Low back pain approximately affects 80% of the population. It is extremely common and thus continues to affect millions of people every year. It is a difficult condition to treat effectively and so it causes a huge financial burden on the patients as well as the hospitals. For the accurate diagnosis of low back pain, a good patient history, physical exam and diagnostic imaging are important. Causes of low back pain may range from spinal stenosis, sacroiliac joint pain, facet joint pain, myofascial joint pain etc.(2, 3). One of the most common causes where sacroiliac joint pain is overlooked is in low back pain. It is common to relate neurological signs to protruding disc and it is also common to confuse it with discogenic pain or radicular low back pain.(4)

Sacroiliac joints (SIJs) are responsible for 13% to 42% of low back pains. (3) It is often overlooked because of its complex nature. (5)It is the cause of pain in 10% to 25% of patients with mechanical low back pain with or without leg symptoms according to Thawrani et al. (6) According to Raj MA et al, up to 25% of low back pain can arise from the sacroiliac joint. (7)

In 1905, Goldthwaite described SI joint pain as the mixed source of lumbar pain. This interest in sacroiliac joint as one of the sources of lumbar pain decreased when Mixter and Barr reported that the intervertebral disc could be a leading cause of lumbar pain. (8) Although sacroiliac joint pain is very common and often encountered, physicians have difficulty diagnosing the dysfunction due to less progress in the area of diagnosing, differential diagnosis and the lack of a gold standard test for the dysfunction. The diagnostic criteria was set by Merskey and Bogduk describing the pain originating from SIJ and radiating to hip or the legs, pain in SIJ with provocation tests was also a diagnostic criteria, and pain resolving with blocks or local anesthetic was the last criteria for diagnosis of SIJ pain. (8)

Sacroiliac joint is the joint between the sacrum and ilium bones of pelvis which are connected by strong ligaments. he joints is strong; it transfers the weight from lower limb to spine with irregular elevation and depression that produces interlocking of two bones. It is hypomobile in nature and stabilized European guidelines are published and denied sacroiliac joint dysfunction as a pain experienced between posterior iliac crest and gluteal fold particularly in vicinity of sacroiliac joint. The pain may radiate to posterior thigh. The endurance capacity for standing, walking and sitting is diminished. (9)

The SIJ is the largest axial joint of the body; it is a di-arthrodial joint with unique anatomic and physiologic characteristics. These unique characteristics are often the reason of it going undiagnosed. It connects the spine to the pelvis and thus leads to load transfer between the upper body and the lower limbs. It lies between the ilium bones and the sacrum. Its motion is limited to 2 to 4 mm in each direction. It is a very stable joint due to the tight bands of ligaments and pelvic floor muscles surrounding it as well as its irregular and rough surface. These reasons make it extremely stable. (7, 10) SIJ pain has many causes; traumatic or atraumatic, that range from hypo-mobility, hyper-mobility, capsular tension, ligamentous tension, compression or shear forces etc. Other reasons include pregnancy, repetitive stresses, spine fusion surgery, and high impact activities such as road traffic accidents and something as simple as jogging or soft tissue injury from a fall to the buttocks, or sudden or repeated lifting of heavy weights. Pelvic ring fractures are also a leading cause. (6, 7).

When it comes to sacroiliac joint dysfunction (SIJD), the etiology has not been properly identified yet. Some of the factors supposedly held responsible are trauma, joint laxity, and degenerative joint disease (degenerative changes resulting in SIJ dysfunction are common in aging). Joint laxity is highly observed in females with a raised incidence rate in pregnancy. It was reported by Bernard and Cassidy that 58% of the cases of sacroiliac joint dysfunction are due to minor trauma such as a fall to the buttocks. (11, 12)

In a study conducted by MD Zhixiang et al, it was found that the patients with lumbar disc herniation had worse sacroiliac joint degeneration. In patients who had lumbar disc herniation with more pathological alterations, symptoms etc. had a significantly more amount of SIJ degeneration.(3)

Practitioners diagnose low back pain with the help of a CT scan and it is usually effective but the diagnostic value of CT imaging in SIJD is poor. Thus, practitioners diagnose SIJD using a combination of low back pain with changes such as osteophyte formation, reduced joint space and subchondral sclerosis. These are naturally occurring in the older population and those with a high BMI. (3)This is also difficulty because the pain mimics other causes of low back pain. (13)For an accurate diagnosis. Clinical imaging along with provocation tests are helpful for the accurate diagnosis of sacroiliac joint dysfunction. (6, 14)

The SIJ is part of kinetic chain that connects the spinal column and lower extremities. Depending on clinical setting, it may be a direct or indirect pain generator and should be evaluated frequently in the assessment of back or leg problems. The SIJ is especially perplexing in that it may resemble lumber and hip spine diseases as well as emerge from surgical therapy of spine and hip problems. Yoshihara claimed that, some patients may have worth less lumber fusion due to frequently misdiagnosed sacroiliac syndrome.⁽¹⁵⁾ Joint dislocation after trauma or during pregnancy, arthritis/sacroiliitis, and degenerative changes all can cause symptoms. .According to Ha et al.,⁽¹⁶⁾ 75 percent of patients showed degenerative SIJ abnormalities visible on radiographic imaging after 5 year of lumber posterior fusion.

Many tests exist that check the sacroiliac joint dysfunction but there is no one specific and sensitive test that exists for diagnosis. However, there are certain tests that are still carried out to rule out in differential diagnosis. These tests are the FABER test which stands for (flexion, abduction, and external rotation test) the distraction test, the lateral compression test, sacral thrust test and thigh thrust test. FABER, compression and thigh thrust are found to be more valid for the diagnosis. Furthermore, a positive for 3 or more tests is a definitive diagnosis  (5)

Particularly, manipulation, exercise and kinesio-taping are proven helpful as a treatment. (17)This study aims to find the prevalence of sacroiliac joint pain in patients with lumbar disc herniation. Less literature in the past exists that looks at the prevalence of SIJD in this scenario.