A Unique "Reverse" Crescent Fragment in an Anterior-Posterior Compression Fracture: A Case Report

We describe a patient with an anterior-posterior compression type pelvic fracture sustained after a motorcycle crash, with pubic symphysis disruption and a "reverse" crescent fragment. The injury force ruptured the anterior sacroiliac ligaments and travelled posterior medially, creating a complete Denis zone 2 sacral fracture, rather than rupturing the posterior sacroiliac ligaments as would be expected. The patient underwent open reduction and internal fixation of the pubic symphysis and closed reduction and percutaneous pinning of the right sacroiliac joint.

This case presents a unique "reverse" crescent fragment not previously described in the literature as an anterior-posterior compression type III variant.