The sacroiliac joint (SIJ) is a large L shaped joint that connects the base of the spine (sacrum) to the pelvis (ilium). The SIJ is surrounded by large ligaments which give the joint a large degree of stability. As a result the SIJ only moves a very small amount and research has confirmed this in standing and lying positions.
Due to the inherent stability of the SIJ, it is able to withstand large compressive loads and hence it is designed for force transfer or load transfer from the legs and pelvis into the spine.
The SIJ can cause pain which commonly occurs directly over the joint or into the buttock. SIJ pain accounts for 15% of chronic non-specific low back pain and is common during or after pregnancy, during sport and it can also occur as a result of a fall onto the buttocks.
Pregnancy related low back and pelvic girdle pain (PLBP) is more prevalent and is reported to occur in 48-71% of pregnant women. Research has shown pelvic floor dysfunction (the muscles that support the perineum) exists in 52% of women with this condition and hence these muscles need to be accurately assessed by a Pelvic Floor Physiotherapist in women with PLBP.
Most SIJ conditions are non-specific, meaning that there is no radiological cause for the presenting pain and hence investigations are often not warranted.
- buttock pain, sharp catching pain directly over the joint
- pain aggravated by walking, standing, rolling in bed, single leg standing
- often relieved with pelvic belt
Other conditions can refer directly to the SIJ and can mimick an SIJ problem such as;
- Lumbar spine dysfunction
- Sacroiliacitis (inflammatory disorder associated with Ankylosing Spondylitis)
- Piriformis syndrome
- Hip joint pathology
As a result, a thorough assessment is required to determine the exact cause of the pain and the underlying contributing factors. The most common cause of SIJ pain is a lack of force closure, meaning the stabilising muscles around the pelvis are not compressing the SIJ properly such as the lower abdominals and gluteals. Conversely, if these stabilising muscles are overactive, SIJ pain can result. As mentioned previously a pelvic floor assessment may be warranted especially if there is associated reports of incontinence or constipation.
Management is focussed around re-training the low abdominals and gluteals with specific stabilisation and strengthening exercises. Taping the SIJ and using pelvic belts can often help to relieve the pain. Manual therapy such as massage and mobilisation of stiff spinal segments can be helpful. Once adequate stability across the SIJ has been achieved further functional strengthening such as squatting, stepping, lunging and lifting can be incorporated into the routine and taken into daily life. Pilates is then a good form of low-impact exercise to further develop functional strengthening and maintenance of gains made.