A 53 year-old woman with no past medical history stepped out of the house to walk her dog when she slipped on the icy front stairs. She noted immediate pain and an obvious deformity of her right ankle, but denied head strike, loss of consciousness, or other symptoms.
On physical exam, the there was appreciable skin tenting over the ankle deformity, as well as a nearby abrasion across her lateral malleolus. She was neurovascularly intact, but the ankle was immediately reduced, due to skin tenting. She thinks she remembered scraping the ankle while on the ground but was not positive about that fact. With the reduction performed, the next step was to determine if the fracture was open or not...
An open fracture occurs when a fracture site communicates with the outside environment. Open fractures have much higher rates of infection, up to 25%, depending on a number of factors. The most important way to reduce infection rate is early administration of antibiotics, so prompt identification of an open fracture is crucial.
Another consideration with open fractures is to remember that compartment syndrome is still possible, despite the soft tissue disruption. One study found that, among patients with open tibial fractures, the rate of compartment syndrome was 9.1%., although tibial fractures tend to develop compartment syndrome more often than other locations, so the rates associated with other sites is likely lower.
Interestingly, the majority of open fractures occur with low energy mechanisms. The most common mechanism is crush injury, followed by ground-level falls and motor vehicle crashes. There is also a bi-modal distribution with most high-energy open fractures occurring in young males and most low-energy injuries occurring in elderly females. Finger phalanges are the most common sites, followed by the tibia and distal radius.
Generally, the worse the open fracture, the higher the rate of infection. Fractures are graded on a number of scales, but the most commonly used is the Gustilo Classification, which correlates with infection rate:
|Fracture type||Definition||Infection rate (%)|
Wound <1 cm; minimal contamination,
|II||Wound >1 cm; moderate soft-tissue
damage, minimal periosteal stripping
|III A||Severe soft-tissue damage and substantial
contamination; coverage adequate
|III B||Severe soft-tissue damage and substantial
contamination; coverage inadequate
|III C||Arterial injury requiring repair||
Other factors that increase the rate of infection include the bacterial contamination, diabetes, age > 80, tobacco use, location of the fracture, malignancy, and immunocompromised state.
Some open fractures are easy to diagnose, but many will be more subtle. For injuries unrelated to the joint, copious irrigation and cleaning of the site, followed by sterile probing is the standard of care.
A potential traumatic arthrotomy, or open joint, has historically been diagnosed with a saline load test (SLT). The amount of fluid necessary to achieve 95% sensitivity varies by joint, but the most common are:
155 mL for knees
55 mL for ankles
40 mL for elbows
7 mL for wrists
Emerging evidence, though, is supporting heavier reliance on advanced imaging to diagnose traumatic arthrotomy. One study found 100% sensitivity and specificity for finding air in potentially open knees using computed tomography, compared to 92% when SLT was performed on this same group of patients. Meta-analyses show that more research is needed into both SLT as well as using CT imaging for the diagnosis of traumatic arthrotomy.
In addition to standard treatment for a fracture (analgesia, immobilization, neurovascular exam etc.), open fractures warrant:
Immediate antibiotics (first generation cephalosporin)
Orthopedic surgery consult
Irrigation and debridement
Antibiotics within 3 hours of injury have been associated with a six-fold decrease in infection, so early administration is critical. For irrigation and debridement, one study recommended very low pressure sterile saline irrigation, as re-operation rates were no higher when comparing the low pressure and high pressure groups.
After reducing the patient’s ankle, the emergency department provider probed the patient’s soft tissue injury but was unable to track to bone. Was this simply an abrasion from the ice? Could it be skin breakdown secondary to the swelling? Was it an injury from a fracture fragment?
The orthopedic surgery team evaluated the patient and were also unsure whether or not the wound communicated with the fracture site. In fact, this is a relatively common situation, as the injury has time to clot, the bones have shifted, and full wound exploration in the emergency department is difficult.
In this case, the injury was treated as an open fracture and the patient was immediately given antibiotics. She was admitted to the hospital to undergo a thorough washout and debridement in the operating room.
Take Away Points
When in doubt, treat a fracture with associated soft tissue injury as open
Use antibiotics as soon as possible
Do not discount the mechanism, as most open fractures occur from low energy injuries
Compartment syndrome is still possible
If you see air in the joint on imaging, it is an open fracture
Faculty Reviewer: Dr. Jeffrey Feden
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