Sacroiliac joint (SIJ) dysfunction is often associated with pregnancy or post partum mums, but can also be related to overuse injuries (repeated bending activities) or sporting incidents. The SIJ does not have a very large range of movement, but is an integral central component of the skeleton in full weight bearing (walking and running), and it is therefore essential that biomechanically the joint is moving in a coordinated fashion bilaterally.
The SIJ is part synovial and part fibrous, and gains stability from both force closure (muscle actions around the pelvis) and form closure (the shape of the joint itself, including the irregular shape of the joint surfaces).
Pain is often local to the SIJ but may refer into the buttock and even down the posterior thigh. Groin pain is possible particularly if there is a pubic symphysis problem.
Pain is often aggravated by standing, walking and running, although this is not always the case. A common complaint is pain when rolling over in bed.
Lying supine with the knees bent can take pressure off the joint. If there is frank instability, such as in the later stages of pregnancy, a SIJ compression belt can offer a lot of relief. SIJ compression belts can also relieve pain during functional activities in patients who are being treated for SIJ dysfunction for a variety of other causes, and is often considered by the physiotherapist.