High and low pressure pulsatile lavage of contaminated tibial fractures: An in vitro study of bacterial adherence and bone damage

Objective: This study was designed to examine the effect of pulsatile irrig ation on microscopic bone architecture and its time-dependent efficacy in r emoving adherent slime-producing bacteria from cortical bone. Design: Using an in vitro model, ten-millimeter transverse cut sections fro m five human tibiae were contaminated with Staphylococcus aureus and subjec ted to either high pressure pulsatile lavage (HPPL; seventy pounds per squa re inch, normal saline) or low pressure pulsatile lavage (LPPL; fourteen po unds per square inch, normal saline) or served as controls. Alteration of b ony architecture was quantified by using a previously described ordinal sca le and histomorphometric analysis of each transverse cut section of tibia. To assess the time-dependent effectiveness of pulsatile lavage in removing adherent bacteria from bone, ten-millimeter transverse cut sections from te n canine tibiae were contaminated with S. aureus and subjected to high or l ow pressure pulsatile lavage immediately or after one, three, or six hours. Scanning electron microscopy and bacterial cultures were used to assess th e removal of adherent bacteria. Results: HPPL resulted in significantly greater macroscopic damage than was seen with LPPL or in controls (ANOVA, p < 0.001). Histomorphometry reveale d that HPPL was associated with significantly larger and more numerous fiss ures or defects in the cortical bone when compared with low pressure irriga tion (p < 0.001). However, high and low pressure lavage were associated wit h similar degrees of periosteal separation from the cortical bone surface ( p = 0.87). Both high and low pressure lavage were effective in removing adh erent bacteria from bone at three hours irrigation delay, but only high pre ssure lavage removed adherent bacteria from bone at six hours delay. Conclusion: In this in vitro study, compared with HPPL, LPPL led to less st ructural damage and was equally effective in removing bacteria within three hours debridement delay; however, the efficacy of LPPL at six hours debrid ement delay is questionable. This finding may have clinical significance in the development of infection following open tibial fractures.