The histology of “reactive lines” in well-fixed components

The histologic findings from 2 total knee arthroplasties (TKAs) in 1 patient who died 5 years after surgery are reported. Cement was placed under the tibial and femoral metal backs but not around the stems. All components were securely fixed. “Reactive lines,” present around the tips of the stems on radiography, were seen to contain thin, soft connective tissue without debris or macrophages. The histologic features of a reactive line are described. Copyright 2003, Elsevier Science (USA). All rights reserved.