High-pressure pulsatile lavage irrigation of contaminated fractures: effects on fracture healing.

To evaluate the effects of high-pressure pulsatile lavage (HPPL) irrigation on new bone formation and fracture union in a contaminated intraarticular fracture, 45 New Zealand white rabbits were divided into three equal groups. The control group (C) underwent an osteotomy of the medial femoral condyle, contamination with a slurry of clay mixed with Staphylococcus aureus, stabilization and closure. The bulb syringe and pulsatile groups (B and P) underwent an identical procedure, with the addition of irrigation with 11 of saline by bulb syringe or pulsatile lavage system. Two fluorescent bone stains that mark new bone formation were administered subcutaneously: xylenol orange at the time of surgery and calcein green one week postoperatively. Animals were euthanized two weeks postoperatively and femurs were retrieved for histological analysis. Union was determined by examination of microradiographs. The viability of bone along the osteotomy site in the first and second weeks after irrigation was determined by evaluation of the two fluorescent stains. The density of new bone two weeks after irrigation was assessed by digitization of the microradiographs. Nonunion was present in 77%, 53%, and 43% of animals in groups C, B, and P, respectively. There was an increase in the presence of bands of both fluorescent stains along the osteotomy site in the groups B and P compared to group C. There was no statistically significant difference between groups B and P in either fluorescent stain. On digitization of microradiographs, there was more calcified new bone on postoperative day 14 in group P than in either group B or C (p = 0.04). The addition of contamination and foreign material to an intraarticular fracture model results in lower rates of new bone formation and fracture union. Irrigation in this setting is clearly beneficial, whether the irrigant is delivered by bulb irrigation or by HPPL. The results of this study indicate using HPPL in this setting does not cause greater damage than using bulb syringe irrigation.