Abstract
INTRODUCTION
The number of patients undergoing total hip replacement surgery is rising and thus the number of periprosthetic fractures is set to increase. The risk factors for periprosthetic fractures include osteolysis, rheumatoid arthritis, osteoporosis and use of certain types of implants. Evidence from literature suggests that the mortality rate within one year is similar to that following treatment for hip fractures thus as surgeons it is important for us to understand the various management strategies of these fractures.
MANAGEMENT
Acetabular periprosthetic fractures are uncommon and classified into Type I, in which the acetabular component is radiographically stable and Type II, in which the acetabular component is unstable. It is better to prevent than to treat these fractures.
Femoral periprosthetic fractures have several classifications the most commonly used is the Vancouver classification (fig 1).
Type-A fractures are proximal and can involve the greater or lesser trochanter. These are often related to osteolytic wear debris and therefore revision of the bearing surface with bone grafting is recommended. AG involves the greater trochanter and AL involves the lesser, and these can usually be stabilised by cerclage wires supplemented by screws or plates if required (fig 2).
Management of type B fractures is more controversial and will be discussed in depth with reference to all recent papers at the meeting and data from the Swedish Joint Registry. In summary the management is shown in fig 3.
In type-C fractures, one should ensure the fixation device bypasses the femoral stem by at least 2 diaphyseal diameters. Management is as shown in fig 4.
DISCUSSION
The incidence of periprosthetic fractures is rising and effective management involves a multi-disciplinary approach, and begins with taking a careful history to identify co-morbidities, pre-fracture mobility, and pre-fracture symptoms of loosening or acetabular erosion. Use of NSAIDs and smoking status should be noted. Examination findings should focus on mental status, any signs of infection, neurovascular status and the integrity of the soft tissue envelope. Clear radiographs are required to effectively comment on bone quality and the identification of any pathological lesions. White cell count, CRP and ESR should help confirm the absence of infection and if any doubt exists, a pre-operative aspiration should be considered. Ideally surgery should be performed within 2 days of fracture by a revision arthroplasty surgeon, followed by monitoring on a high dependency unit.
With regard to the formulation of an operative strategy, certainly there is no substitute for careful assessment of remaining bone stock, diameter of the canal, fracture configuration and patient-related factors. There is a paucity of data in the current literature relating to the management of acetabular fractures. Displaced femoral fractures are managed with cerclage fixation along with bone grafting of any osteolytic lesions and revision of the bearing surfaces.
Regarding femoral periprosthetic fractures it would appear that one should err on the side of long stem revision arthroplasty +/− impaction allografting should any doubt exist around loosening of the implant since this reduces the one-year mortality rate and the risk of failure.
