Session III - Clinically Relevant Research

High Pressure Pulsatile Lavage Irrigation of Fresh Fractures: Effects on Fracture Healing

Douglas R. Dirschl, MD, Gregory P. Duff, MD, Theodore Miclau, MD, Laurence E. Dahners, MD, Matthew Edin, BA

University of North Carolina, School of Medicine, Chapel Hill, North Carolina, USA

Hypothesis: High pressure pulsatile lavage irrigation of fresh intraarticular fractures devitalizes bone and leads to lower rates of new bone formation in the fracture site than does bulb syringe irrigation.

Conclusion: In this study, pulsatile lavage irrigation devitalized more bone, led to less new bone formation at the fracture site, and produced a lower rate of fracture union than did bulb syringe irrigation, which was equal to controls.

Material and Methods: Thirty adult New Zealand white rabbits were divided into 3 groups. The control group (C) underwent arthrotomy of the knee, osteotomy of the medial femoral condyle, stabilization with a lag screw, and closure of the wound. The bulb syringe and pulsatile lavage groups (B and P) underwent the same procedure, with the addition of irrigation with 1 liter of normal saline, delivered from a standardized distance with either a bulb syringe or a commercially available pulsatile lavage system, prior to fracture stabilization. Each rabbit was administered two fluorescent bone stains: xylenol orange at the time of operation, and calcein green 7 days following operation. The rabbits were euthanized 14 days after operation and the operated femurs retrieved for histological analysis of the fracture site and articular cartilage. Fracture union was determined by analysis of microradiographs, and the density of new bone formed at the fracture line was determined by computerized digitization of standardized areas of the fracture site. The presence and location of fluorescent bands in relation to the fracture line were determined by fluorescent microscopy.

Results: Twenty percent of fractures in groups C and B and 33% of fractures in group P had not united. Digitization of microradiographs at the proximal (cortical) extent of the fracture line revealed 70 ± 4% (mean ± SEM) of the area to be filled with new bone in group C, 62 ± 7% in group B, and 48 ± 11% in group P. Similar measurements at the distal (articular) extent of the fracture line revealed 62 ± 7% new bone in group C, 58 ± 9% in group B, and 41 ± 9% in group P (p = 0.07). This shows a trend, especially at the distal fracture line, towards less bone formation in group P, although statistical significance at the 95% confidence limit was not reached. All specimens had fluorescent bands of calcein green (administered at day 7) the entire extent of the fracture line and bands of xylenol orange (administered at day 0) at the proximal end of the fracture line. Xylenol orange staining extended a mean of 66 ± 8% and 65 ± 6% of the distance from the proximal to distal ends of the fracture line in groups C and B, respectively. In group P, however, the mean extent of orange staining was only 44 ± 5% of the fracture line (p<0.05).

Discussion: Based on the results of this study, high pressure pulsatile lavage irrigation appears to decrease the formation of new bone in the fracture site, an effect most pronounced at the end of the fracture line nearest the irrigation source. Since the pulsatile lavage group showed significantly less viable bone adjacent to the fracture site immediately after irrigation than did the other groups, it appears that pulsatile lavage irrigation devitalizes more bone in the portion of the fracture nearest the irrigation source. High pressure pulsatile lavage irrigation has been shown to be very effective for the removal of particulate matter from soft tissues, but the results of this study indicate that it may have a deleterious effect on fracture healing. We recommend, therefore, that high pressure pulsatile lavage irrigation not be used routinely, but only for fractures requiring mechanical debridement of particulate matter.