M. Glyde, BVSc, MACVSc, MVS, HDipUTL, DECVS
At the end of this session, you will be able to:
- Use the grading system for open fractures to decide treatment options
- Recognise the significance of a full-thickness skin wound over a fracture
- Decide on appropriate antibiotic use for open fractures based on an understanding of the difference between contamination and infection
Open fractures are a common presentation in small animal practice. The longstanding approach to managing open fractures has been open wound management and the use of external skeletal fixators (ESFs). This “traditional” approach has been associated with a relatively high occurrence of non-union resulting in the need for revision surgery and, in some cases, limb amputation. Prolonged open wound management leading to “treatment fatigue” of both owners and veterinary staff, significant ongoing patient morbidity and often the development of multiresistant bacteria are also associated with this older-style approach.
More recently, through a better understanding of managing traumatic wounds and a better understanding of fracture biology, newer approaches to managing open fractures have been developed that limit or avoid many of the negative issues associated with “traditional” treatment of open fractures. These newer approaches concentrate on early primary closure or early delayed primary closure of open wounds through a variety of strategies in combination with fracture stabilisation with bone plates.
This session will focus on the following key points:
- The treatment of an open fracture on initial presentation affects the outcome. Open fractures are contaminated initially rather than being infected. Infection will only develop if wound management is not appropriate. Infection is more likely with prolonged open wound management and in the presence of poor soft tissue blood supply.
- The majority of infections in open fractures are acquired in hospital. The long-term prophylactic use of antibiotics in open fractures is not justified and encourages the establishment of resistant bacteria within your practice.
- Longer courses of antibiotics if infection does develop is justified but should be based on cultures of deep tissue samples from the fracture site.
- Classifying the type of open fracture helps determine both the prognosis and the recommended treatment options.
- Primary or delayed-primary wound closure following appropriate debridement improves blood supply to the healing fracture, reduces morbidity, reduces the likelihood of producing resistant bacteria, saves time and in most cases is ultimately cheaper than ongoing open wound management.
- ESFs in many severe open fractures (type III) will not last the distance until the bone is healed and will fail or need revision before the fracture has healed.
- Bone plates and interlocking nails are not contraindicated in open fractures. Early re-establishment of healthy well-vascularised soft tissue over a healing fracture speeds fracture healing and reduces the occurrence of infection.
- Should implants be removed after fracture healing? Implants placed in open fractures may be contaminated and so there is some degree of risk of future cryptic infection developing. How likely this is to occur in canine and feline open fractures is not clear. Currently owners should be advised that bone plates probably should be removed on completion of fracture healing.
Open Fracture Classification
Identifying the type or severity of open fracture is useful in determining the prognosis and in deciding on the treatment options available in that case.
Open fractures may be divided into three types based on the severity of the injury.
Type I open fractures are low-energy fractures where an open wound typically less than 1 cm is created by the internal force of a bone fragment protruding through the skin. These have a small external skin wound that in many cases is not apparent until the hair is clipped for surgery.
Any full-thickness skin wound near a fracture should be classed as open. Probing the wound to determine whether it connects with the fracture is contraindicated, as this will carry bacteria and debris into the soft tissues and fracture site.
Type II open fractures involve higher energy trauma in which the soft tissue wound is created by a combination of internal and external force. There is more damage to the soft tissues than with a type I. The skin laceration is larger than a type I, but sufficient tissue exists to close the wound without needing to use a skin flap or other advancement technique.
Type III open fractures are the most severe type and result from high-energy external trauma such as gunshot injuries and motor vehicle trauma producing shearing injuries. Extensive skin and soft tissue injuries exist. There is insufficient soft tissue to cover the wound.
Complications including infection are significantly higher in type III fractures reflecting the greater degree of soft tissue compromise. Type III open fractures can be repaired with very good outcomes; however, this requires considerable financial and time commitment on the owner’s part to achieve a good outcome.
Open wound management of type III open fractures is prolonged and expensive and is nearly always complicated by the development of significant infection, including the establishment of multiresistant bacteria.
Early primary closure or delayed primary closure of type III fractures usually “short-circuits” prolonged open wound management, reduces morbidity and the occurrence of infection, speeds fracture healing and is ultimately cheaper and less time-consuming than open wound management.
In most type III open fractures, treatment with an ESF will facilitate open wound management, but the ESF will rarely last long enough without revision for the fracture to heal. In most cases where an ESF is used, revision surgery or replacement with a bone plate is necessary.
It is not contraindicated to use bone plates or interlocking nails in severe open fractures.
Management of Open Fractures
Protect the Wound from Nosocomial Contamination
Open fractures should be covered with a quick sterile dressing to prevent further contamination while patient assessment and stabilisation is underway. In a study of open fractures in people, it was found that 80% of infections were hospital-derived, with only 20% of subsequent infections developing from bacteria present on initial presentation.
It is important when applying temporary support to open fractures at this stage to not reduce protruding bone fragments, as this will further contaminate the soft tissues at the fracture site. Reduction of any protruding bones should not be performed until after debridement.
Administer Intravenous Antibiotics
Early administration of broad-spectrum intravenous antibiotics as soon as possible on presentation has been shown to reduce subsequent infection rates. The degree of soft tissue compromise in type III open fractures means that these are more susceptible to infection than both type I and type II fractures.
The most common bacteria present in open fractures are gram-positive bacteria such as Staphylococcus spp. and Streptococcus spp. and gram-negatives such as E.coli, Pseudomonas, Klebsiella. First- or second-generation cephalosporins or intravenous forms of potentiated amoxicillin/clavulanic acid are appropriate.
Addition of a fluoroquinolone has been shown to be beneficial in reducing infection rates in type III open fractures in humans.
It is important to differentiate both the concepts of prophylactic and therapeutic antibiotic usage and contamination and infection.
Antibiotics should be administered prophylactically for three to five days initially, then subsequent administration either prophylactically or therapeutically based on exit cultures or deep tissue cultures in response to clinical signs of infection if indicated. The long-term usage of antibiotics is only indicated in established osteomyelitis and is not routinely necessary in open fractures.
Type II and type III open fractures should be debrided prior to fracture stabilisation ideally as soon as the animal is physiologically stable for anesthesia for debridement. Type I fractures rarely need debridement preoperatively.
Debridement should be performed in a sterile surgical manner. The wound should be covered in clean single-use K-Y jelly, which is water miscible and protects the wound from the hair and debris of clipping. After clipping, the K-Y jelly is cleaned away as part of the surgical preparation. A full surgical preparation should be performed. Do not use open or multi-use K-Y jelly.
The wound should be explored in a sterile manner. It is important to remember that open fractures are biologically compromised areas and as such are more susceptible to infection than normal sites.
Copious lavage with warm sterile isotonic saline should be undertaken. Use of a sterile giving set, three-way stopcock, 35-ml syringe and 18-gauge needle will facilitate this. Given the large amount of fluid used, the use of waterproof drapes and/or suction is advisable to minimise the risk of nosocomial contamination, as cloth drapes will be rendered non-sterile once wet.
Sharp debridement of necrotic tissue and any particulate matter should be performed. Bone fragments that have soft tissue attachments should be minimally disrupted. Small bone fragments with no soft tissue attachments should be discarded. In severe injuries where there is some doubt over the viability of soft tissue, serial debridement over several days will enable subsequent identification of devitalised tissue.
Controversy exists over the value of entrance or exit cultures. An exit culture at the time of major debridement and, if definitive fracture repair surgery is delayed, then again at the time of fracture repair.
Type I open fractures rarely require any debridement prior to definitive fracture stabilisation; however, the same approach to lavage should be undertaken at the time of fracture repair as with the more severe types.
Definitive Fracture Repair
Rigid stability is essential in the repair of open fractures. For this reason, intramedullary pins, orthopaedic wire and external coaptation are contraindicated in open fractures.
External skeletal fixators (ESFs) have been reported to be the fixation method of choice in types II and III open fractures (provided a sufficiently rigid frame can be placed). This dogmatic advice should be carefully considered, as in many type II and nearly all type III open fractures definitive fracture repair with an ESF is usually not achieved. This is because the poor biology of types II and III open fractures means that healing will be prolonged and, in most cases, the ESF will fail before the fracture has healed.
ESFs have several theoretical benefits in open fractures:
- ESFs provide rigid stability remote from the fracture site. This minimises soft tissue damage and reduces the likelihood of infection localised around the implant.
- ESFs allow easy access for open wound management.
- ESFs are useful in radial and tibial open fractures (which are the most common sites of open fracture).
The reality, however, is that the majority of ESFs placed will fail to a greater or lesser degree prior to completion of fracture healing in more severe open fractures necessitating ESF revision or transfer to some form of internal fixation. In some cases, revision surgery of the ESF with removal of loose pins and replacement with other pins may be effective. In most cases, however, removal of the ESF completely and replacement with a bone plate and bone graft to manage the delayed or non-union that has developed is necessary.
It is advisable to inform owners prior to surgical management of type II and type III fractures with an ESF that initial treatment with an ESF to facilitate open wound management followed by definitive treatment with internal fixation once the open wounds are resolved will be necessary.
Bone plates, interlocking nails or ESFs are suitable for type I open fractures, as they all can provide sufficiently rigid stability. Bone plates are the implant most commonly used in managing type I open fractures.
Bone plates and interlocking nails can be used for types II and III open fractures. In our practice, bone plates are used in preference to ESFs in types II and III fractures provided that the open wound can be closed either primarily or through delayed-primary closure. To achieve this in severe fractures usually requires closure of the wounds with axial pattern flaps or other soft-tissue transfer methods. This has the dual advantage of closing the open wound and replacing traumatised tissue with robust well-vascularised tissue that is much more resistant to soft tissue infection.
The advantage of bone plates and interlocking nails over ESFs is that they have greater longevity, which is often necessary in more severe open fractures.
Owners should be advised prior to surgery that removal of the bone plate after fracture healing is advised to reduce the risk of future cryptic infection that can potentially occur when implants are placed in contaminated sites. ESFs also require subsequent surgery to remove, although removal is relatively simpler than bone plate removal.
Cancellous bone grafting is recommended in open fractures managed with open reduction. Direct placement of a graft is usually possible in types I and II open fractures and in all type III fractures where primary closure or delayed primary closure is performed. Where prolonged open wound management is elected in type III fractures, bone grafting cannot be performed until healthy granulation tissue has covered the fracture site. The graft is usually placed at a second surgery through a separate incision to the open wound through an area of good soft tissue coverage.
Where ever possible, closure of open wounds in type III open fractures using an axial pattern flap or pouching or other methods of closing the wound with well-vascularised robust soft tissue is preferable to ongoing open wound management. This improves outcome, minimises morbidity, minimises treatment time, and is ultimately cheaper than prolonged open wound management.
Dos of Open Fractures
- Do place a quick sterile dressing to cover the open wound while treating the animal for shock. This will reduce the likelihood of the traumatised soft tissue wound picking up a hospital-derived infection.
- Do provide temporary splint support with the initial sterile dressing in fractures that are distal to the elbow or stifle joint. This will greatly reduce the animal’s pain and limit ongoing damage of the soft tissue envelope of the fracture from the fractured bone ends.
- Do give prophylactic intravenous broad-spectrum antibiotics on initial presentation and for the first few days only until the results of the bacterial deep tissue culture obtained at surgery (the “exit” culture) are obtained. If the exit culture at the time of surgery grows bacteria, then this suggests an established or an establishing infection and requires a therapeutic course of antibiotics.
- Do appropriately lavage and debride open wounds associated with fractures to reduce the amount of devitalized tissue and contamination.
- Do use an appropriate method to close an open wound and minimize the need for ongoing open wound management. Closure should be with healthy well-vascularised soft tissue that is not under tension.
Don’ts of Open Fractures
- Do not use long-term antibiotics prophylactically. This will increase the likelihood of developing resistant bacteria. Only use long-term antibiotics therapeutically to treat a confirmed bacterial infection. The choice of antibiotic should be based on culture and sensitivity identification of a deep tissue sample or swab from the fracture site.
- Do not obtain superficial tissue or discharge samples for bacterial culture. They will not represent what, if any, bacteria are present at the fracture site.
- Do not use ESFs for definitive treatment of open fractures unless the fracture will heal relatively quickly before the ESFs begin to fail. Most type III and many type II open fractures will not heal before the ESF fails, necessitating revision surgery. Owners should be advised prior to treatment that a 2-stage surgery with ESF and open wound management followed by further surgery with a bone plate, etc., may be necessary.