HIGH-PRESSURE PULSATILE LAVAGE OF CONTAMINATED HUMAN TIBIAE - AN IN-VITRO STUDY

Objective: This study was designed to examine the effect of high press ure pulsatile lavage (HPPL) on bone destruction and propagation of bac teria in experimentally contaminated human tibiae. Methods: Using an i n vitro model, nine human tibiae from above-knee amputations were test ed. A mid-diaphyseal tibial shaft fracture was created, and each end o f the fracture was contaminated with bacteria (six tibiae with Staphyl ococcus aureus, three tibiae with Escherichia coli). The proximal end was designated as the control and the distal end was the test site. Th e test site was debrided by HPPL (seventy pounds/square inch, 1,200 mi lliliters/minute, 1,050 cycles/minute) with three liters of normal sal ine, whereas the control site did not receive any form of irrigation. Serial sections at increasing distance from the fracture site were cul tured and the numbers of bacterial colony-forming units (CFUs) were de termined at each level. The degree of macroscopic architectural change in each serial section was graded on an ordinal scale. Results: Analy sis of culture data revealed a reproducible pattern of bacterial propa gation into the intramedullary canal. Peak bacterial seeding occurred at two to three centimeters from the fracture site (p = 0.023, Wilcoxo n signed rank test). The degree of bone destruction varied proportiona lly with the depth into the canal and was found to be predictive of th e extent of bacterial propagation determined by culture data. Conclusi on: 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 clinic al significance.