M Bhandari1, A Adili, R J Lachowski. 1. Department of Orthopaedic Surgery, McMaster University, Hamilton, Ontario, Canada.
Abstract
OBJECTIVE: This study was designed to examine the effect of high pressure pulsatile lavage (HPPL) on bone destruction and propagation of bacteria in experimentally contaminated human tibiae. METHODS: Using an in vitro model, nine human tibiae from above-knee amputations were tested. A mid-diaphyseal tibial shaft fracture was created, and each end of the fracture was contaminated with bacteria (six tibiae with Staphylococcus aureus, three tibiae with Escherichia coli). The proximal end was designated as the control and the distal end was the test site. The test site was debrided by HPPL (seventy pounds/square inch, 1,200 milliliters/minute, 1,050 cycles/minute) with three liters of normal saline, whereas the control site did not receive any form of irrigation. Serial sections at increasing distance from the fracture site were cultured and the numbers of bacterial colony-forming units (CFUs) were determined at each level. The degree of macroscopic architectural change in each serial section was graded on an ordinal scale. RESULTS: Analysis of culture data revealed a reproducible pattern of bacterial propagation into the intramedullary canal. Peak bacterial seeding occurred at two to three centimeters from the fracture site (p = 0.023, Wilcoxon signed rank test). The degree of bone destruction varied proportionally with the depth into the canal and was found to be predictive of the extent of bacterial propagation determined by culture data. CONCLUSION: In an in vitro model of a contaminated fracture, HPPL resulted in bacterial seeding into the intramedullary canal and significant damage to the architecture of the bone. These observations might have clinical significance.
OBJECTIVE: This study was designed to examine the effect of high pressure pulsatile lavage (HPPL) on bone destruction and propagation of bacteria in experimentally contaminated human tibiae. METHODS: Using an in vitro model, nine human tibiae from above-knee amputations were tested. A mid-diaphyseal tibial shaft fracture was created, and each end of the fracture was contaminated with bacteria (six tibiae with Staphylococcus aureus, three tibiae with Escherichia coli). The proximal end was designated as the control and the distal end was the test site. The test site was debrided by HPPL (seventy pounds/square inch, 1,200 milliliters/minute, 1,050 cycles/minute) with three liters of normal saline, whereas the control site did not receive any form of irrigation. Serial sections at increasing distance from the fracture site were cultured and the numbers of bacterial colony-forming units (CFUs) were determined at each level. The degree of macroscopic architectural change in each serial section was graded on an ordinal scale. RESULTS: Analysis of culture data revealed a reproducible pattern of bacterial propagation into the intramedullary canal. Peak bacterial seeding occurred at two to three centimeters from the fracture site (p = 0.023, Wilcoxon signed rank test). The degree of bone destruction varied proportionally with the depth into the canal and was found to be predictive of the extent of bacterial propagation determined by culture data. CONCLUSION: In an in vitro model of a contaminated fracture, HPPL resulted in bacterial seeding into the intramedullary canal and significant damage to the architecture of the bone. These observations might have clinical significance.