The sacroiliac joint (SIJ) can become dysfunctional through trauma and/ or pregnancy. The mechanism involves direct or repetitive microtrauma to the buttocks/ lower back. Treatment with specialised physiotherapy alleviates the problems in ~ 80% of cases. The remainder may respond to prolotherapy (hypertonic glucose injections into the dorsal intra-osseous ligament (DIOL) after multiple injections. We hypothesised that the response may be more rapid with injection of platelet enriched plasma (PRP) into the DIOL under ultrasound guidance.