The Sacro-iliac joint (SIJ) is a diarthrodial joint located at the transition between the spine and lower limbs which is subjected to major shear forces. SIJ mobility is minimal but escalated during pregnancy and the post-partum period. It is important to be aware of the anatomy and physiology of the SIJ.

The SIJ connects two variably undulating cartilage surfaces, contains synovial fluid. It is enclosed within a capsule strengthened by several ligaments. A recently published literature review published in 'Orthopaedics & Traumatology: Surgery & Research' focused on the micro-traumatic lesions associated with SIJ.

A micro-trauma induces chronic SIJ pain, which needs to be differentiated from hip pain and spinal pain. The diagnosis is based on the particular clinical provocation tests combined with a local injection of an anaesthetic. The findings were normal for magnetic resonance imaging and radiographs.

The non-operative treatment using the exercise therapy and stretching is intended primarily to strengthen the latissimus dorsi, hamstring muscles and gluteus to increase the SIJ coaptation. Other physical therapies have not been proved useful. The radiofrequency denervation of the dorsal sensory rami was somewhat useful, but the effects tend to subside over time. Minimally invasive SIJ fusion by trans-articular implantation of screws or plugs has provided success rates and may be advantageous for patients with refractory pain.

According to Jean CharlesLe Huec et al. (review authors), "Well-designed RCTs are required to validate the different recommended techniques, some of which seem devoid of a biomechanical rationale."