Intra-articular fragments in acetabular fracture-dislocation.

Acetabular fractures are often associated with dislocation of the femoral head. When the dislocation is reduced, > or = 1 fragments may remain inside the joint, especially in posterior dislocation. In this kind of dislocation, the fracture of the posterior wall of the acetabulum may be comminuted. The fragments attached to the joint capsule or free may remain between the femoral head and the acetabulum. During reduction, these fragments are dragged inside the joint. The presence of the fragments in the hip joint may prevent complete reduction of the dislocation. Surgery should be performed early to reduce the risk of aseptic necrosis of the femoral head. Sometimes the fragments derive from a fracture of the femoral head without involving the posterior wall. Fragments are difficult to detect by conventional radiography; therefore, computed tomography scans are always indicated in fracture-dislocations pre- and postoperatively to check that all intra-articular fragments have been removed and the fracture has been reduced. We observed 373 cases of acetabular fracture between January 1, 1997 and December 31, 2007. One hundred twenty-seven cases presented a dislocation: 5 anterior, 13 central, and 109 posterior. In 45 cases, after reduction of the dislocation, 2 anterior and 43 posterior intra-articular fragments were observed. Removing a loose body inside the joint is always necessary because movement causes damage of the cartilage and therefore an early arthritis. The strategy to remove and the approach differs according to the kind of dislocation observed.