Concepts in wound irrigation of open fractures: ‘Where we came from, and where are we now?

Abstract

Wound irrigation is described as the flow of a solution through an exposed fracture surface to reduce the microbial colonization, to remove apparent foreign particles and wound exudates. . While recent literature and various in-vitro and in-vivo trials have cleared some clouds of doubt from the mind, it still remains a topic of debate. Normal saline remains the standard irrigation solution as it is non tissue toxic and has the same tonicity as body fluids. The quantity and duration of washing though is not standardized and is the surgeon's choice. This adds to the dilemma in the minds of the surgeon, with the timing of the debridement and the duration of wound irrigation depending on the surgeon's discretion. Future studies should aim to regulate the duration of the wound irrigation besides guiding about the ideal fluid volume to be used for the irrigation. Further, secondary end-points like the duration of hospital stay, rate of infections and use of hospital resources, should be computed to know about the adequacy of the wound debridement and irrigation. Antimicrobial solutions can kill microorganisms in the wound but are toxic to the host tissues as well, which limits their use. In addition, pulsatile (high pressure) lavage has not been seen to increase overall effectiveness. Recent research trials have found cumulative use of innovative solutions like phenols and EDTA along with enzymes to be encouraging though large randomized controlled trials are lacking.

1. Introduction

Open fractures have always posed a challenge in orthopedics and their management protocols have changed over the past few decades.¹ Colossal steps have been taken since the time of Franco-Prussian war and American Civil War, where the open fractures were dealt with emergency amputation to shrink the risk of ongoing infection leading to sepsis and death.¹ An estimate of 6 million fractures occur in the United States per year,^2,3 out of which only 3% are open fractures, while, in India more than 4.5 million open fractures are reported every year.^4,5 The gold standard in the treatment of open fractures is an early intervention with copious irrigation and meticulous debridement of the wound having equal importance as the stabilization and fixation of the fracture decreasing the morbidity and mortality of these injuries.⁶ Over the past century, there has been extensive research on the same and debates rage over an ideal irrigant, the necessary quantity of irrigant, the pressure of the lavage and the timing of debridement for the management of wounds in various trauma scenarios, as they may improve the outcomes.^6,7 The quantity and the time for which bacteria are present in a wound is associated with the danger of infections, accentuating the importance of wound irrigation.⁷ (see Table 1)

Table 1.

Studies depicting the role of irrigation pressures and various irrigating agents in open fractures and wounds.

Authors	Models	Treatment groups and Irrigants	Inferences
In-vitro studies
Bhandari et al.28 (1998)	Cut section of tibiae injected with Staphylococcus aureus and Escherichia coli with normal saline	No irrigation vs HPPL at 70 psi	Macroscopic destruction of the bony architect
Bhandari et al.23 (1999)	Humans and animals tibiae inoculated with S.aureus and treated with LPPL or HPPL,NS after 0,3, and 6-hr delays	No irrigation vs LPPL at 14 psi and HPPL at 70 psi	Macroscopic and microscopic bone destruction with HPPL with decrease bacterial adherence at 6- hours
Bhandari and Schemitsch28 (2002)	Bone marrow cultures	Low-pressure BSL, high-pressure lavage at 8 psi	High-pressure lavage resulted in an increase adipocytes and decreased osteoblasts
Anglen et al.34 (1994)	Sheep's gluteal muscle	No irrigation, LPL, HPPL	HPPL showed higher bacterial counts at deeper depths than LPL and control
Bhandari et al.8 (2001)	Stainless steel cortical bone screw inoculated with Staphylococcus epidermidis	No irrigation, NS, BAC, CS, NEO, P-NEO	CS with power irrigation showed the lowest number of bacterial load while bulb syringe with antibiotics showed elevated level of bacteria similar to no irrigation
Animal studies
Dirschl et al.24 (1998)	Skull cells and canine tibiae (T) inoculated with staph. aureus	NS, 1% and 10% EtOH, 1% and 10% PI 1% and 4% CHG, 1% and 10% Soap, 1% and 10% BAC	NS and soap were least toxic to cells, while PI, CHG, EtOH, and BAC were most toxic and 1%PI and1%CHG were effective in reducing bacterial load in tibiae. However, soap with LPL showed no bacterial load.
Rosenstein et al.37 (1989)	Intra-articular distal femoral Osteotomy of a rabbit irrigated with NS	No irrigation, BSL, HPPL at 70 Psi	Lesser new bone formation at the end of 1week and more at 2 nd week, using HPPL
Conroy et al.33(1999)	Dogs fractured shaft femur inoculated with S.aureus	No irrigation, NS, BAC	Decreased rate of cultures with lesser systemic and local complications were seen in BAC group at 1st and 4th week
Adili et al.16 (2002)	Rats contaminated spinous process, inoculated with Pseudomonas aeruginosa and S. aureus and irrigated after 15 min	NS, BzC, CS, BAC	CS showed decreased rate of P.aeruginosa compared with NS; BzC showed increased rate of P.aeruginosa; BzC decreased S. aureus compared with NS; CS did not decrease S. aureus; BzC was associated with wound complications.
Owens et al.28 (2009)	Open mid-shaft femoral fracture Complex wound model: in a Goat	No irrigation, BSL, HPPL at 70 Psi	In biomechanical testing at 3 weeks, HPPL group had a lower peak bending force and decreased stiffness compared with BSL and control groups; no differences observed at 6 weeks
Human Studies
Longmire et al.52 (1987)	Traumatic wounds <24hrs	BSL, HPPL, NS, HPPL, BzC, CS	Bacterial count after immediate and 48hrs of irrigation showed that at 48hrs the HPPL group showed higher levels of bacteria than the BSL group also NS group at 48hrs had the lowest number of bacteria while the CS group had the highest.
Anglen19 (2005)	Open fractures of lower extremity	NS irrigation with BSL at 0.05 psi, needle syringe lavage at 13 psi	Needle syringe irrigation resulted in decreased infection rate from 6.9% to 1.3%
Bhandari et al. and FLOW Investigators20 (2015)	Open fractures of lower extremity	BAC,CS	Wounds washed with BAC had higher chances of poor healing (9.5%) as compared with CS group (4%); no differences in infection and bone-healing rates were seen.
	Open fracture requiring fixation	Gravity irrigation at 1–2 psi, LPL at 5–10 psi, HPPL at 20 psi, With irrigating agents NS, CS	There was no significant difference in the rate of reoperation amongst 3 pressure groups. While NS group had a lower reoperation rate (11.6%) compared with the CS group (14.8%)

Pulsatile lavage has been found to be effective in decreasing quantity of microorganisms from the wound initially but have led to increased soft tissue damage, profound increase in microorganisms count after 72 h and increase rate of wound infections.^8,9 Contrary to this, low pressure irrigation aid in adequate healing process, but may not be able to remove the foreign particles and the bacteria.^8,9 Petrisor et al. in their survey; FLOW (Fluid lavage in patients with open fracture wounds) reported that around the globe there exists a dilemma amongst surgeons as to what is the best irrigant solution, the ideal volume of irrigant and the optimum pressure to be used.¹⁰ The present overview aims to find an effective and simple irrigation method and agent and management protocols for satisfactory wound irrigation, when presented with an open fracture in the acute setting.

2. Quantity of fluid

Previous literature recommends “liberal,” “ample,” or “sufficient” amounts of irrigation, with no specific guidelines on actual amount of volume to be used. Amount ranging from 3 to 15 L in an open fracture wound is recommended at times with no literature supporting the data, while others have described these figures as capricious.¹¹ Many institutes still prefer the simple protocol of Gustilo-Anderson classification which refers to a simple algorithm of using volume of irrigant to the grade of open fracture, which is 3 L normal saline for grade 1 fractures, 6 L normal saline for grade 2 fractures, and 9 L normal saline for grade 3 fractures.¹² However, there is no outcome data to support these recommendations.^13,14 Though some animal studies have been performed analyzing an optimal quantity of irrigant solution ranging from 100 to 400 ml and reported decrease in amount of microorganisms with increase in volumes, there is lack of clinical trials on humans, which leads to dilemma for operating surgeons as to what should be the minimum irrigant solution volume for satisfactory wound irrigation.15, 16, 17 Further, analyzing the previous literature, the ideal volume of the irrigant should be based upon the gross contaminants present in the wound, adequacy of the debridement, size of the wound, surrounding soft tissue trauma and energy of the trauma (fracture configuration).

3. Delivery pressure, pulsatile lavage

Conventionally, irrigation of the wound was done either with a bulb syringe irrigation set bag or an intravenous set.¹⁸ With the advent of high pressure devices like pulse lavage, their use has gained momentum. Whereas the previous studies favored the use of high pressure compared to low pressure lavage and reported good results in animal models and human studies, the recent studies including the FLOW trial reports use of low pressure lavage for optimal management of the wounds.^13,19, 20, 21

Brett et al. in their study highlighted the great discrepancy in the interpretation of the pressure grades between different surgeons.²² Further, different irrigation devices impart different range of pressure specifications, which can be detrimental.²² Where recent literature quotes pressures between 10 and 20 psi as low and between 35 and 70 psi as high, many studies in past reporting good outcomes with high pressures, have used pressures between 1 and 10 psi as low and pressures between 11 and 20 psi as high, adding to the controversy, as whether they were limited by the wrong classifications of pressure.^8,22, 23, 24, 25 In light of the evidence in the literature, pressures between 1 and 10 psi can be labeled as low, 11 to 19 psi as intermediate and ≥20 psi as high.²⁴

Several previous studies on wound irrigation, reported that high pressures lead to greater incidence of infection, greater amount of bacterial colonization after 72 h, decreased rates of fracture union, reduction in the overall strength of the bone with changes in the trabecular network of the bone, affecting the ability of the stem cells to convert to bone forming cells, and risk of incorporation of the microorganisms in the medullary canal.^9,22,23,26, 27, 28 Contrary to this, Lee and Carprise reported that high pressures are capable of removing more particulate and dirt matter from the wounds.^26,29 Further, Bhandhari et al. reported that wound irrigation is time dependent and that wounds which are more than 6 h old, need high pressure pulsatile lavage to decrease the quantity of particulate matter and microorganisms adhered to the bone and soft tissues.³⁰ The current recommendations from the FLOW trial suggest that non-pulsatile flow irrigation is the ideal form of irrigation method in most of the cases and that high-pressure pulse lavage should be used at the prudence of a surgeon, by assessing the wound, the surgical delay and the contamination present.³⁰

4. Type of irrigating solution

There had always been a lack of clear consensus when it comes to the use of various irrigating agents, so it poses a challenge for orthopedic surgeons to cautiously weigh the theoretical advantages and disadvantages of the irrigant used. These agents may act as a double edged sword for the wounds pulling out the debris on one hand while damaging an already friable zone of injury by their chemical reaction causing tissue necrosis and impairing wound healing. Some literature supported the use of physiologic saline as the first choice, followed by povidone-iodine, hydrogen peroxide, chlorhexidine, and antibiotic solution in descending order of their use as other mediums, with an aim to prevent infection.³¹ Broadly there are four categories of irrigating agents that have been used in the treatment of open fractures: antiseptics, surfactants, antibiotics, and normal saline solution.

Normal Saline Solution: Due to the less cytotoxicity, non hemolytic nature, isotonic nature and cost effectiveness of normal saline, it remains the standard for wound irrigation as compared to other antibiotic and antiseptic irrigant solutions.32, 33, 34, 35 While previous experimental studies showed greater effectiveness of surfactants^34,35 and antiseptics⁸ in removing bacteria, recent studies on experimental models suggest the use of normal saline solution, reporting it's superiority to antibiotic, surfactant and antiseptic solutions after open fracture^24.In the FLOW trial, patients in which wound irrigation was performed with sterile isolated normal saline, were observed to have lower rates of infection postoperatively compared to patients who received wound irrigation with normal saline incorporated with castile soap^14. While findings are not always consistent^34,35 current evidence based literature suggests use of normal saline due to its greater efficacy in removing the contaminants and less rates of re-infections compared to other irrigant solutions.

Antiseptics: In previous literature, many experimental studies on animals and humans have been done to see effect of antiseptics. Though antiseptics have been found to have a broad spectrum activity, with bactericidal, virucidal and fungicidal properties which helps in reducing the pathogen load from the wound, there exists damaging effects on the bone and soft tissues and delayed wound healing. Povidine iodine, benzalkonium, chlorhexidine gluconate and hydrogen peroxide are some of the antiseptics using which various animal and human studies have been carried out. Bhandari et al. in their experimental animal study on mice calvarial cells reported no additional effects of antiseptics over normal saline and found cytotoxic effects on bone forming cells.⁸ Kaysinger and Lineaweaver in their respective experimental studies noted that even at high dilutions, antiseptics additives including povidine iodine, sodium hypochlorite and hydrogen peroxide killed the fibroblasts.^29,36 Penn-Barwell and Platt observed that chlorhexidine gluconate was not superior to normal saline at removing bacteria from the wound.^37,38 Though various invitro studies with different additives have been carried out on human cells, only povidine iodine has been used for invivo studies in humans.³⁹ While Sanderson et al. found significant reduction in microbial count from wound with povidine iodine; Rogers et al. did not found any statistically significant decrease in microbial count with povidine iodine in the wound relative to the normal sterile.^40,41 Further, Vilijanto et al. noted that povidine iodine effected the wound healing and thus should be avoided⁷⁷. These clinical studies point towards the use of normal saline over various antiseptic additives and that these antiseptives have a negative influence on the wound healing affecting the microvascular blood flow and endothelial lining structure.⁴²

Antibiotics: Antibiotics prevent and treat bacterial infections through bactericidal and bacteriostatic mechanisms.⁷ Due to different pharmacokinetic properties and their efficacy, not all the antibiotics can be instilled while irrigating the wounds.⁷ The most widely used antibiotics are neomycin, bacitracin and polymyxin with varying mechanisms of action.^7,34 While mechanism of action of neomycin remains to be controversial, bacitracin and polymixin acts by inhibiting the cell membrane synthesis and cell permeability respectively.³⁹

Some experimental studies on animal studies have reported that antibiotics decrease the quantity of the microorganisms from the wound surface when compared to other irrigants.^7,34,43 Contrary to this, several studies have reported additives including antibiotics to have negative influence on the wound healing and increase reinfection rates when compared with surfactants like castile soap and sterile normal saline.^7,8,24,34 In a RCT by Stevenson for management of open distal phalanx fractures, use of flucloxacillin was found to be no additional effect when compared to normal saline.⁴⁴ In another RCT by Anglen et al., castile soap was found to be equivalent to antibiotic (bacitracin) in reducing the quantity of bacteria from wound surface without affecting the union rates.¹³ Administration of antibiotics promotes antibiotic resistance and is also costly as compared to saline.^8,24,34 Further, allergic reactions with antibiotic solutions have been observed which further preclude its use.^45,46 In order to target the bacteria specifically they need to be cultured first and then targeted but it takes time which may lead to further contamination.⁴⁷ It is recommended to irrigate the wound as early as possible, as antibiotics and irrigation are less effective once bacterial biofilms are formed.⁴⁸ Sparse evidence in literature related to the same and less number of large clinically controlled trials like randomized controlled trials (RCT) add to the dilemma. Currently available data in the literature negates use of irrigant like antibiotics for wound irrigation.

Surfactants: Soaps are the commonly used surfactants which act as emulsifiers to reduce the bacterial quantity from the wound surface.³⁴ Soaps forms micelles incorporated with bacteria, which gets washed away from the wound surface.³⁴ Studies have found that castile soap wash is superior to alternative additives including antiseptics and antibiotics.^7,8,13,34 Bhandhari et al. in his animal experimental study reported soaps to be effective in reducing the microbial count from the wound surface without affecting the rate of wound healing and fracture union rates.⁸ They further added that there was minimal reduction in the overall cell density when compared with other irrigant additives.⁸ In addition, they compared the irrigant pressures with soaps and reported that soaps led to maximum removal of the microorganisms from the wound when irrigation was done with low pulsatile lavage compared to the normal saline.⁸ Contrary to this an experimental study by Owens et al. reported a regrowth of bacteria at 48 h post wound irrigation with castile soap compared to the normal saline.²⁴ This controversy was addressed by the FLOW trial, which stated that castile soap has no additional benefit compared to the normal saline and thus low evidence for surfactants was reported.¹⁹

5. When to irrigate

Wound irrigation after open fractures has always been considered to be an urgent procedure. A 6-h rule since 19th Century, found that early irrigation reduced the risk of infection despite the absence of much evidence.⁴⁹ Gustilo-Anderson open fractures classification signifies the augmented rates of infection with increased grades, even though no correlation has been found with the timing of the surgical intervention.^50,51 Timely irrigation may remove bacteria sooner, curbing their multiplication at the wound site thus mitigating the chances of infection as found in some studies.^52,53 In an experimental animal study, high pressure lavage was found to be beneficial in cases where operative intervention was delayed by more than 6 h.²² Comprehending this, Owens et al. reported that bacteria adhesion post 3 h of injury prevented their removal due to stronger bonds with the bone and soft tissues and thus advocated earlier wound irrigation.⁵⁴ However, many studies showed no association of an increased rate of infections to the delay in surgical intervention^55–58. Schenker et al. in their systematic review reported no increased rates of infection when surgical intervention was done within 6 h or after 6 h.⁵⁵

Analyzing the current available literature, adequacy of the debridement, early administration of the antibiotic and the continuous irrigation rather than pulsatile high pressure irrigation seems to be an ideal choice for the wound irrigation.

6. Future trends

The surgical knife and isotonic saline remain the standard of care which all other forms of tools for debridement revolve around and have to be compared to. In addition to optimizing volume, and mode of delivery, future development of irrigants that can directly target the bacteria and the biofilm could become the cornerstone of the treatment of open fractures. One hypothesis stated that ethylenediaminetetraacetic acid (EDTA) and phenol remove adherent bacterial infection more effectively than saline solution, with the role of calcium chelators present in EDTA disrupting the outer membrane of bacterial cell wall with its divalent cations such as Mg2+⁵⁹. It also removes lipopolysaccharide from the cell wall, exposing phospholipids, making anti-microbial agents more effective even at lower concentrations, while phenol acting as a demulcent helps in removing the adherent protein without damaging the host tissues.^60,61Various other alternatives in form of enzymes and laser have been designed and studied with little evidence, having benefits of hemostasis and depth of surgical excision.^62,63

7. Overview

• •Irrigation and debridement remain to be the gold standards for proper wound care.
• •Early administration of intravenous antimicrobials is of utmost importance in decreasing the rates of infections and enhancing functional outcomes.
• •Evidence based medicine suggests use of sterile normal saline over other irrigants for optimal results after wound irrigation.
• •Optimal amount of volume and temperature required depend largely on the discretion of the surgeon assessing the current condition of the wound.
• •A surgeon should err on the side of caution and use larger amount of irrigation than using a minimal amount.
• •Low pressure irrigation remains to be the ideal method for wound irrigation.

Funding

There is no funding source.

CRediT authorship contribution statement

Ravi Gupta: Conceptualization. Atul Rai Sharma: Writing – original draft. Akash Singhal: Writing – original draft. Sumukh Shail: Writing – review & editing. Gladson David Masih: Writing – review & editing.

Declaration of competing interest

The authors had no conflict of interest related to research and authorship is granted to only those individual who have contributed considerably to the manuscript.