EFFICACY OF WASHING TECHNIQUES FOR MORSELLISED ALLOGRAFT IN IMPACTION GRAFTING.

Abstract

Introduction: Revision arthroplasty using the impaction grafting technique is an increasingly popular technique. The lost bone stock is replaced rather than substituted with ever increasing amounts of metal. There have been many advances in the understanding of this technique in recent years. It has recently been shown that washing of the graft improves the biomechanical strength, bony ingrowth and biocompatibility of morsellised allograft bone. The aim of this study was to identify the most efficacious method of washing morsellised allograft in the operating room.

Methods: Fresh frozen femoral heads identified for research purposes were randomly divided into four groups. Group A was washed using a serial dilution technique at 37°C, group B serial dilution at 60 °C, group C pulsed lavage wash at 37°C and group D pulsed lavage wash at 60 °C. Three-gram samples of each femoral head were taken prior to washing. The heads were then washed according to the grouping. The unwashed and washed morsellised bone was then assessed for the presence of protein, haemoglobin, DNA and lipid using spectrophotometric analysis techniques. The removal of these marrow components from the femoral heads in each group was assessed as a proportion of the original content.

Results: All washing techniques removed a large proportion of the marrow load of the femoral heads. The most efficacious technique was washing by serial dilution (removal rate 67.5–87.4%). Washing by pulsed lavage removed less marrow (28.4–80.9%). Protein showed the highest removal rate (80.9–86.4%) and haemoglobin the lowest (28.4–67.5%). Removal of lipid was most affected by temperature with a larger proportion removed at 60°C as compared to 37°C.

Conclusion: We conclude that the most efficient method of washing morsellised allograft bone for impaction grafting is by serial dilution with fluid at 60°C. This information should improve the results of impaction grafting, as it is known that cleaner bone results in improved biomechanical stability, enhanced biological compatibility and accelerated bony ingrowth.