Clinical and Roentgenographic Evaluation of Bipolar Prostheses with Noncemented Anatomic Medullary Locking Femoral Stems

Bipolar hip arthroplasty has enjoyed increasing popularity in recent years. A bipolar prosthesis is believed to offer the advantage over an endoprosthetic replacement of decreasing frictional wear of the acetabulum by allowing motion at both the concave and convex surfaces of the cup. Other theoretical advantages include a possible reduction in stem loosening, a decline in incidence of dislocation. and ease of revision to total hip arthroplasty. While initially used primarily as an alternative to fixed endoprosthetic arthroplasty for femoral neck fractures and avascular necrosis, the role of bipolar hemiarthroplasty has been expanded to include treatment of nonunion of femoral neck fractures, femoral head fractures, degenerative hip arthritis, and revision of failed total hip arthroplasty. These conditions are often also indications for total hip arthroplasty using a fixed acetabular component. There remains much discussion in the literature regarding treatment recommendations for the various hip joint pathologies.