CURRENT TREATMENT OF PERIPROSTHETIC FRACTURES

Abstract

Periprosthetic fractures are becoming an increasing problem because of the number of total joint replacements that are performed yearly as well as the increase in longevity of the patients that receive total joint replacement. the risk factors for intraoperative fracture are rheumatoid arthritis, cementless arthroplasty, metabolic bone disease, Paget’s Disease, complex deformities, and revisions. The risk factors for post-operative fracture are weakened bone secondary to stress risers, screw holes, cortical perforations and stem tip protrusion, loose implants, and osteolysis. As a general rule the surgeon should make sure that all stress risers such as cortical windows and holes in the diaphysis should be bypassed at least two times the shaft diameter with a longer stem which restores the strength of the shaft to approximately 80%. Areas of transition between stem tips and plates or stem tips and stem tips should be avoided. Cortical strut grafts over holes, windows, and in areas of transition are of value. Johannsen’s Classification with a Type I fracture being proxmial to the tip of the stem, Type II fracture being around the tip of the stem, and Type III fracture distal to the tip of the stem is of value. In a cementless implant the majority of fractures are type I with the minority being Type II and Type III. In periprosthetic fractures with a well fixed prosthesis, the surgeon should maintain the components, restore alignment, and restore function. In periprosthetic fractures with a loose prosthesis, the surgeon should revise the components,restore alignment,and restore function. Treatment options for an intact prosthesis include cerclage wiring in high fractures and the use of plating and allograft struts in lower fractures. With loose implants, treatment options include removal of the implant while maintaining as much bone stock as possible. A loose implant must then be replaced and longer stems and cortical strut grafts are options in the reconstruction. Weight bearing is delayed to allow fracture healing. With this knowledge in hand, the orthopaedic surgeon can anticipate problems and reconstruct bony lesions causing periprosthetic fracture with some confidence in his mechanical constructs.