Neutrophils are active in total joint implant loosening

Background Polymorphonuclear neutrophils (PMN) are the first cells to take part in the local foreign body reaction in aseptic loosening of endoprostheses. The aim of this study was to evaluate the systemic host reaction to total joint replacement by measuring the production of nitric oxide by neutrophils before and after total joint replacement.Patients and method Blood samples were collected from 33 patients (27 hips and 6 knees) before surgery, and 2 weeks, 2 months and 2.5–3 years after surgery. The levels of nitric oxide produced by PMN were measured by the method described by Markert et al. (1994).Results Patients reporting pain in the region of the implant 3 years after surgery, and also patients with radiographic signs of loosening, had higher production of NO in the early period and 3 years after the implantation than those with good clinical results.Interpretation We propose that elevated levels of nitric oxide production by PMNs may serve as a marker of total joint prosthesis loosening.