Ch 40 open fractures Flashcards
What percentage of traumatic appendicular fractures in dogs and cats are classified as open?
14% dogs
29% cats
What regions of the body are at the highest risk for development of an open fracture after trauma?
Scapula
Radius and Ulna
Tibia and Fibula
Tarsus - At or distal to the tarsus is at the greatest risk
What is name of the classification scheme used for open fractures?
Define each grade
Gustilo-Anderson Open Fracture Classification Scheme
Type 1: Wound <1cm in size, often formed from in-to-out. Surrounding soft tissue is mildly/moderately contused
Type 2: Wound >1cm in size, without extensive soft tissue damage/flaps/avulsions. Often from out-to-in trauma
Type 3: Extensive soft tissue damage
3(a) - Adequate soft tissue coverage of fractured bone despite extensive laceration of flaps
3(b) - Extensive soft tissue loss, periosteal stripping and bone exposure. Usually associated with massive contamination
3(c) - Arterial injury requiring repair
Tx goals (5)
prompt and aggressive debridement of contaminated material and nonviable tissue
wound irrigation
administration of antimicrobials;
restoration of soft tissue coverage to heal
fracture stability
What percentage chlorhexidine solution can be used on the surrounding skin and in the wound?
lavage with?
4% solution for skin
0.05% solution for in wounds - Provide antibacterial activity without causing tissue reactivity
vs sterile isotonic fluid at a desired pressure of 7 to 8 psi.
The authors of a prospective, randomized, double-blinded study found that only 18% of open fracture infections were caused by organisms cultured at the time of initial presentation.
Numerous studies have demonstrated that the organism cultured initially (i.e., the contaminating organism at the time of presentation) is not the organism that ultimately causes infection
In humans, what time period for administration of ABx has been shown to significantly reduce the risk of infection?
Within 3 hours after injury - Reduces infection rates to 4.7% from 7.4%
What is the recommended ABx treatment for each type of open fracture?
Type 1 and 2 - 1st or 2nd gen cephalosporin
Type 3 - Combo of 1st or 2nd gen cephalosporin and a fluoroquinolone
Continuation of antibiotics, should be guided by results of aerobic and anaerobic C&S.
the decision to continue antibiotic therapy is best based on post–surgical debridement samples.
increase the risk of infection include
failure to administer antibiotics
resistant organisms
delay from injury to initiation of antibiotic therapy,
extensive soft tissue trauma
positive culture obtained following debridement-irrigation.
common bacteria
Ab’s covering Gram-positive and Gram-negative aerobic and anaerobic organisms
Staphylococcus spp., Streptococcus spp.,
Klebsiella spp.,
Pseudomonas spp.,
Clostridium spp.,
Enterobacter spp.
Escherichia col
What are the reported infection rates for each type of open fracture in humans?
Type 1 - 1-2%
Type 2 - 2-10%
Type 3 - 10-50%
What are the reported delayed union and non-union rates for each type of open fracture in humans?
Type 1 - 0-5%
Type 2 - 1-14%
Type 3 - 2-37%
In humans, what aspects of treatment of open fractures resulted in fewer infections?
Treating all with emergent surgical debridement
Administering ABx before surgical stabilisation
Primarily closing type I and II Fx
Delayed closure type III
Using no internal fixation (ie. opting for ESF)
Decreased infection rate to 5% from historical control of 12%
What percentage of open Fx infections are cause by the organism which is cultured on presentation?
18%
Suggests that the majority are nosocominal Ix, highlighly the importance of prompt wound care and coverage
How did antibiotic beads effect the infection rate of open fractures in humans?
Combining ABx beads in surgical site with systemic ABx therapy decreased infection rate from 12% to 3.7%
What is the recommended pressure for wound lavage?
How is this achieved?
7-8psi
Accomplished using a 1L fluid bag with an external pressure sleeve at 300mmHg
What are the benefits of VAC techniques in wound therapy of open fractures?
What pressure is this applied at?
Benefits:
- Decreases interstitial oedema
- Increases tissue blood flow
- Accelerates formation of granulation tissue
- Increases bacterial clearance
- Promotes wound contraction
- Effective method of securing skin
Applied at 125mmHg intermittently or continuously
What option is there if there is not enough soft tissue to cover the fracture as in type IIIb? How has this effected infection rates in humans?
Can use pedicle muscle transfers or microvascular free muscle transfers
Reduced infection rates in humans from 30% to 5%
What is the theoretical risk associated with interlocking nail or IM pin in the treatment of open fractures?
The spread of bacterial to the entire medullary cavity
What are some methods to improve fracture healing?
Bone grafts
Bone graft substitutes
Purified recombinant mitogenic or stimulatory factors
When obtaining autogenous graft material for treatment of open fractures, fresh sterile gloves and instruments should be used during graft harvesting
What are the relative risks of different forms of bone grafts?
Cancellous bone graft can be safely placed in a contaminated wound
Cortical bone graft is at risk of infection and subsequently becoming a sequestrum
fracture tx method
Controversy in the human and veterinary literature.
Open fractures have been successfully repaired with internal fixation methods (bone plates, [plate-rod], cerclage wire, and interlocking nails) and external fixation methods (linear, circular, and hybrid external skeletal fixators).
type I > same method of fixation as would be used for a closed fracture
Type II > can often be treated using the same method as for closed fractures
Extensive soft tissue damage associated with type III open fractures may preclude internal fixation
type III internal fixation
Bone plates have been used to treat type I through III open fractures, with satisfactory final results reported for veterinary patients.
Opponents > question the additional disruption to the soft tissues and blood supply
Implants used to treat open fractures may require removal in the future
surgical concept of no metal in a contaminated fracture has been challenged; studies have demonstrated that metal does not stimulate or promote wound sepsis
benefits of fracture stability override any potential harmful effects of implants
ESF for open #
Advantages:
decreased application time
away from the fracture site
easy access for open wound
minimal disruption of tissues
implant removal that is relatively easily
External skeletal fixation has been documented to pose practical difficulties for reconstruction of large soft tissue defects in human beings.
Complications: pin loosening, pin track drainage, infection, delayed union or nonunion, and fixation failure
complications (5)
Superficial infection
deep-seated infection
delayed union or nonunion
necrosis/breakdown of soft tissue repair techniques,
neurologic damage from the initial injury.
Outcomes and Complications Associated with
Acute Gunshot Fractures in Cats and Dogs
Schrock 2022
97, Study Design Review of cats and dogs with radiographically confirmed
20/37 with follow-up > poor fracture outcome
Extensive soft tissue trauma at the fracture site was associated with an increased likelihood of poor outcome.
poor outcomes:
primary limb amputations
osteomyelitis/surgical site infections,
delayed/non-unions
Single institution retrospective study
evaluating the frequency of implant removal
and associated risk factors following open
fracture fixation in 80 cases (2010–2020)
Brea M. Sandness 2023
retrospective study determines the frequency and risk factors for explantation following use of internal fixation.
open wound management and healing by second intention was elected in eight (10.0%)
Major complications ~30%
minor complications 20%
Explantation in 21%. Out of 72 dogs (18%)
cats (50%).
Only diagnosis of postoperative infection was associated with an increased risk of explantation
> 65% due to infection
> 29.4% due to implant failure
Approximately 1 in 5 fractures stabilised using internal fixation can be anticipated to require explantation, with cats potentially being at a higher risk than dogs
isolated plate fixation in 42
(52.5%) cases. Angle-stable interlocking nails were used
in 19 (23.75%) cases, plate-rod technique in 12 (15.0%)
