A simple hip dislocation refers to dislocation without a fracture. Complex fracture-dislocations involve popping the round head of the femur (thigh bone) out of the acetabulum (socket) with a fracture of the acetabulum at the same time. Acetabular fractures affect the joint surface where the head of the femur moves against the joint surface to provide joint motion.
If you can look at it this way, a simple dislocation has some long-term benefits, too. Only one out of every four patients with a simple dislocation results in hip arthritis later. It’s the dislocations accompanied by an acetabular fracture that present later with problems including arthritis. About 88 per cent of those complex fracture-dislocations damage the joint resulting in death of the bone (osteonecrosis) and osteoarthritis.
Simple dislocations are often easier to reduce (set back in place) without major surgery. The patient is still sedated to achieve deep relaxation of the surrounding muscles. But with a few quick and easy techniques, closed reduction is possible.
The more complex dislocations with fractures or other injuries often require arthroscopic or even open-incision surgery. There is a greater risk of complications with loss of blood flow, osteonecrosis (death of bone), infection, and poor outcomes with complex dislocations.