Avascular necrosis of the acetabulum

Abstract

Avascular necrosis of the acetabulum is a complication of an acetabular fracture that can be attributable to both the provocative traumatic event and to a surgical exposure that is undertaken as part of an open reduction and internal fixation. In the former instance, devitalized fragments of bone can arise as free or impacted osseous or osteochondral segments. Surgically induced avascularity follows excessive stripping of soft tissue pedicles from bony fragments. The extensile exposures such as the triradiate or extended iliofemoral or the application of two exposures for the inner and outer pelvic walls are particularly likely to culminate in devitalization of bone. Ironically, an associated fracture with notable comminution and displacement that further jeopardizes the osseous blood supply is the one in which an extensile exposure is likely to be used. Avascular necrosis of bone can present clinically as â fulminant postoperative wound infection in which much of the lateral ilium becomes a sequestrum necessitating its removal. Alternatively, when a total hip arthroplasty is performed for post-traumatic arthritis, after the failure of an open reduction, premature loosening and failure of a cementless cup is a frequent manifestation of acetabular avascularity. Occasionally, the, loose cup erodes through the inner pelvic wall to create a formidable reconstructive problem that may necessitate the application of structural or morselized allograft and the use of a protrussio ring. Once the potential for acetabular avascularity is recognized, the principal therapeutic aim is prevention. Currently, the role for extensile exposures is highly limited. Usually a sufficient exposure for most simple and associated injury patterns can be achieved by resort to a Kocher-Langenbeck or ilioinguinal incision. In the presence of a highly comminuted fracture, particularly in an elderly patient, the statistical likelihood for achieving a successful functional outcome with the open reduction needs to be carefully reviewed. If the likelihood for a favorable outcome is a remote possibility, then instead of a complex internal fixation, an acute total hip arthroplasty with limited internal fixation may be preferred.