High pressure pulsatile lavage irrigation of intraarticular fractures: Effects on fracture healing

Objectives: To evaluate the effects of pulsatile lavage and bulb syringe irrigation on fracture healing in vivo. Design: Randomized prospective trial in an animal model. Setting: Medical school orthopaedic department. Subjects: Thirty New Zealand white rabbits. Intervention: The control group (C) underwent osteotomy of the medial femoral condyle, stabilization, and closure. The bulb syringe and pulsatile lavage groups underwent the same procedure as group C, with the addition of irrigation with one liter of normal saline via a bulb syringe (B) or a pulsatile lavage system (P). Animals were administered two fluorescent bone stains: xylenol orange at the time of operation, and calcein green one week postoperatively. Animals were euthanized two weeks postoperatively and femurs were retrieved for histological analysis. Main Outcome Measures: Union was determined by examination of microradiographs under light microscopy. The viability of bone along the fracture site was determined by evaluation of xylenol orange and calcein green staining under fluorescent microscopy. The density of new bone formed in the osteotomy site was assessed by computerized digitization of standardized regions of the proximal and distal osteotomy. Results: Xylenol orange bands were present a mean of 66 ± 8 percent (mean ± standard error of the mean). 65 ± 6 percent, and 44 ± 5 percent of the distance along the osteotomy in groups C, B, and P. respectively (p < 0.001). Calcein green bands were present throughout the osteotomy site in all specimens. Calcified new bone was present in 62 ± 4 percent, 58 ± 7 percent, and 41 ± 9 percent of the area measured in groups C, B, and P, respectively (p = 0.07). Twenty percent of the osteotomies in groups C and B did not unite, compared with 30 percent in group P (p > 0.5). Conclusions: Pulsatile lavage irrigation of fresh intraarticular fractures in rabbits has a detrimental effect on early new bone formation; this effect, however, is no longer apparent two weeks following irrigation. While this study evaluated the effects of pulsatile lavage irrigation in noncontaminated fractures without extensive soft tissue injury, the detrimental effects observed on early new bone formation may translate to an increased risk of nonunion in the setting of a contaminated open fracture with extensive soft tissue injury. Based on the results of this investigation, the selective use of pulsatile lavage irrigation appears warranted. In the absence of gross wound contamination, irrigation with a bulb syringe appears less likely to impair fracture healing than does pulsatile lavage irrigation. Expansion of the model used in this study to include bacterial contamination and soft tissue crushing may further elucidate the effects of pulsatile lavage irrigation on fracture healing.