The use of megaprosthesis in the treatment of periprosthetic knee fractures

Purpose The optimum treatment for periprosthetic fractures in the region of the distal femur is undefined. Although internal fixation for prostheses which are stable is commonly utilised, this can lead to very prolonged morbidity and failure of the fracture to unite. Where the prosthesis is either loose or infected, revision surgery is required and a 'tumour type' prosthesis can be successfully utilised. Methods The outcome of 27 patients treated by an endoprosthetic replacement for periprosthetic fracture of the distal femur between 1988 and 2013 are reported. Two cases were treated by two-stage revision due to persistent infection. Clinical outcomes were assessed by Knee Society score and Knee Society pain scores. Results All 27 patients mobilised rapidly in the post-operative period and infection where present was eradicated by the technique. There have been no cases of further revision in the patients where clinical follow-up is available. Knee Society scores following treatment averaged 88 and pain scores 43 at six months post-operatively. Eight patients have died during the long study period reflecting the age of the study population. Conclusions The use of a tumour-type endoprosthesis in situations of comminuted periprosthetic fractures associated with a loose prosthesis shows favourable results with low complication rates and rapid mobilisation.