The incidence of periprosthetic fractures is rising significantly as more replacement arthroplasties are performed. They are a potentially devastating complication associated with high morbidity and mortality. Their management is a sub-specialty in itself. This article outlines the principles of the management of periprosthetic fractures of the lower limb.Introduction
An aging population with higher standards of living has led to a steady increase in replacement arthroplasties in developed countries as recorded by the Scandinavian, Australian, UK and Mayo Clinic Registers. The positive outcome of an otherwise successful procedure can be compromised by a periprosthetic fracture (PPF). It is a major problem, associated with high rates of morbidity and mortality.1,2 The prevalence is difficult to ascertain but the consensus is that they are increasing both numerically and in complexity. In 2006 Lindahl et al. reported the cumulative incidence of periprosthetic hip fractures as 0.4%.3 According to the Swedish Hip Registry, PPF is the third commonest reason for revision arthroplasty, after aseptic loosening and dislocation.4 Periprosthetic fractures around a total knee arthroplasty are less common but equally important. They are more common in the distal femur (0.3e2.5%) compared with the proximal tibia (0.39% to 0.5%).
Periprosthetic fractures can be divided into those occurring intra-operatively and post-operatively. Intra-operative fractures are usually caused by the insertion of the stem in the femur or the tibia. The incidence varies with different fixation methods. In the femur, uncemented stems carry a higher risk; Berry et al. report a rate of 0.3% in cemented and 5.4% in uncemented. The rates are significantly higher in revision surgery.
The post-operative incidence of periprosthetic fractures in primary total hip arthroplasties (THA) has been reported by the Mayo clinic registry as 1.1% of total hip replacements done between 1969 and 1999).