CT appearance of sacroiliac joint trauma in children

Subchondral fractures in association with an intact joint space and narrowing of the joint space have not previously been reported with sacroiliac joint trauma in children. The subchondral fractures are thought to occur through the zones of cartilage proliferation and provisional calcification in the growing cartilage of the opposing sacroiliac joint surfaces and the zone of cambium layer of the periosteum in the areas of ligamental insertion, as these may represent structurally weak areas. This type of injury may explain the good long-term results in children with trauma to this region. Widening of the sacroiliac joint space in association with trauma as suggested on plain radiographs may thus not be as common as was previously thought.