Processing of whole femoral head allografts : validation methodology for the reliable removal of nucleated cells, lipid and soluble proteins using a multi-step washing procedure

Abstract

Following the major outbreak of BSE in the United Kingdom in the mid 1980's and the first reported cases of the human disease equivalent, vCJD, in 1996 a number of measures were taken to reduce the risk of secondary transmission of vCJD by blood or surgical instruments. Two cases of probable transmission of vCJD by blood components have now been reported. The Department of Health has recently undertaken a vCJD risk analysis for bone. Although significant uncertainties still exist in the assumptions on which the assessment is based, a few important recommendations were made. These include a recommendation that bone should be processed to remove blood and marrow and that pooling of donations is never advantageous. This study aimed to establish a method of processing whole femoral heads using disposable equipment, with the purpose of removing as much of the marrow components as possible. We are able to remove 98.2% (range 94.5--99.9%) of the nucleated cells and 98.7% (range 97.8-99.4%) of the soluble protein content from within an intact femoral head. This work confirms that the majority of blood and marrow components can be removed without the need for morselising the bone prior to washing.