Infection risk analysis of 101 silver-coated endoprostheses

Abstract

Our aim was to analyse the implant survival and infection rates of 101 consecutive silver-coated MUTARS® (= Modular Universal Tumour And Revision System) endoprostheses implanted at an independent orthopaedic tertiary hospital between April 1, 2011 and December 31, 2018 and to compare them with previous outcomes of the MUTARS® developmental hospitals. In addition, we tested the hypothesis that the infection-free survival rates of silver-coated implants depend on the patient's age, gender, pre-operative diagnoses and anatomical localization of the reconstruction. The cohort included 47 sarcoma resections, 29 revision arthroplasties, 20 metastatic resections, 3 benign bone tumours and 2 primary arthroplasties. Endoprosthesis was located in the distal femur (38 patients), proximal femur (29 patients), proximal humerus (12 patients), proximal tibia (10 patients), pelvis (6 patients), total femur (5 patients) and distal humerus (1 patient). The mean age at implantation was 49 (range 11-86) years and the mean follow-up 3.2 (range 0.1-7.7) years. Twenty-four patients required at least one subsequent revision operation and 15 endoprostheses had to be partially/totally removed. Patients' age was an independent risk factor for postoperative infection regardless of other confounding factors (hazard ratio 1.05 for each year; p = 0.02). With the overall postoperative infection rate 12 % (4 % reinfection + 8 % newly acquired) and cumulative partial/total implant removal rate 25 % after 5 years, complications were comparable to the previous series of the MUTARS® developmental hospitals with high variability between preoperative diagnoses and anatomical localizations. Silver-coated implants show a consistent trend of preventing infections in high-risk body regions and enabling more successful treatment should infection occur, but 10-15 years of clinical follow-up is required for further assessment.