Saline load test

An Open-and-Shut Case? Diagnosis and Management of Open Fractures in the Emergency Department

Case

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...


Background

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.[1]

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%.[2], 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.[3] 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.[4] Fractures are graded on a number of scales, but the most commonly used is the Gustilo Classification, which correlates with infection rate:

Gustilo Classification

Fracture type Definition Infection rate (%)
I

Wound <1 cm; minimal contamination,
comminution and soft-tissue damage

0-2

II Wound >1 cm; moderate soft-tissue
damage, minimal periosteal stripping

2-5

III A Severe soft-tissue damage and substantial
contamination; coverage adequate

5-10

III B Severe soft-tissue damage and substantial
contamination; coverage inadequate

10-50

III C Arterial injury requiring repair

25-50

Other factors that increase the rate of infection include the bacterial contamination[5], diabetes[6], age > 80, tobacco use, location of the fracture, malignancy, and immunocompromised state[7].

 

Diagnosis

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[8]

  • 55 mL for ankles[9]

  • 40 mL for elbows[10]

  • 7 mL for wrists[11]

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[12], 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[13].

Treatment

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

  • Tetanus prophylaxis

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.[1]

Case Conclusion

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


References

  1. FLOW Investigators. A trial of wound irrigation in the initial Management of Open Fracture Wounds. N Engl J Med. 2015;373:2629–41.

  2. Blick SS, Brumback RJ, Poka A, Burgess AR, Ebraheim NA: Compartment syndrome in open tibial fractures. J Bone Joint Surg Am 1986;68: 1348-1353.

  3. Court-Brown CM, Bugler KE, Clement ND, Duckworth AD, McQueen MM. The epidemiology of open fractures in adults. A 15-year review. Injury. 2012; 43(6):891–7. https://doi.org/10.1016/j.injury.2011.12.007.

  4. Okike K, Bhattacharyya T. Trends in the management of open fractures. A critical analysis. J Bone Joint Surg Am. 2006;88:2739–48.

  5. Merritt K. Factors increasing the risk of infection in patients with open fractures. J Trauma 1988; 28: 823–7. doi: http://dx.doi.org/10.1097/00005373-198806000-00018

  6. Lavery LA, Walker SC, Harkless LB, et al. Infected puncture wounds in diabetic and nondiabetic adults. Diabetes Care 1995;18(12):1588–91.

  7. Bowen TR, Widmaier JC: Host classification predicts infection after open fracture. Clin Orthop Relat Res 2005;433:205-211.

  8. Nord R.M., Quach T., Walsh M., Pereira D., Tejwani N.C. Detection of traumatic arthrotomy of the knee using the saline solution load test. J Bone Jt Surg Am Vol. 2009;91(1):66–70.

  9. Bohl DA, Frank RA, Lee SI, Hamid KA, Holmes GE, Lin JO. Sensitivity of the Saline Load Test for Traumatic Arthrotomy of the Ankle With Ankle Arthroscopy Simulation. Foot & Ankle International Vol. 39; 39(6):736-740.

  10. Feathers T., Stinner D., Kirk K. Effectiveness of the saline load test in diagnosis of traumatic elbow arthrotomies. J Trauma. 2011;71(5):E110–E113.

  11. Gittings DJ, Fryhofer GW, Hast MW, Steinberg DR, Levin LS, Gray BL. The Saline Load Test is Effective at Diagnosing Traumatic Arthrotomies of the Wrist. Tech Hand Up Extrem Surg. doi: 10.1097/BTH.0000000000000233.

  12. Konda S.R., Davidovitch R.I., Egol K.A. Computed tomography scan to detect traumatic arthrotomies and identify periarticular wounds not requiring surgical intervention: an improvement over the saline load test. J Orthop Trauma. 2013;27(9):498–504.

  13. Browning BB, Ventimiglia AV, Dixit A, et al. Does the saline load test still have a role in the orthopaedic world? A systematic review of the literature. Acta Orthop Traumatol Turc 2016;50:597–600.doi:10.1016/j.aott.2016.01.004.