Ottawa Ankle Rules

This is part of a recurring series examining landmark articles in Emergency Medicine, in the style of ALiEM’s 52 Articles.

Discussing:  Stiell IG, et al. Decision Rules for the Use of Radiography in Acute Ankle Injuries. JAMA 1993; 269 (9): 1127 – 1132.

 X-Rays for ankle fractures? Is trouble a foot?

With a such a refined Canadian tool you can’t act like a fool.

 The Rules:

Ottawa Ankle

Main Points:

  1. The Ottawa ankle rule is an excellent screening tool for patients with ankle and foot injuries. In this study, it was found to have a sensitivity of 100 percent and is therefore unlikely to miss clinically significant ankle and midfoot injuries.
  2. These simple rules allowed physicians to safely reduce the number of radiographs ordered in patients with ankle and foot injuries by nearly a third.
  3. Based on the combined 1485 patients seen in the two stages the negative likelihood ratio for a fracture is estimated to be 0 for both the ankle and foot series rules!

Background:

Acute ankle injuries are one of the most common presenting complaints seen in the Emergency Department. Ankle radiographs are typically the second most commonly performed musculoskeletal examination, after the cervical spine. It was estimated that more than 5 million ankle radiographs are ordered annually in Canada and the USA with a cost of $500 creating a massive burden on the healthcare systems. Out of all of these images, treatable fractures are present in less than 15 percent of cases.

In 1992, Ian Stiell and his colleagues derived a clinical decision tool for the use of radiography in acute ankle and foot injuries. In the original study, thirty-two clinical variables were assessed for association with fractures seen on x-ray. Using these results, a set of rules were derived to determine if imaging was necessary for patients with ankle and foot injuries who met certain criteria. The goal of the study being reviewed here was to prospectively validate and potentially refine the decision rules to have the highest sensitivity possible, 100 percent, for identifying malleoli and midfoot fractures.

Methods:

The study was set up as a convenience survey and was prospectively administered in two stages: validation and refinement of the original rules, followed by validation of the refined rules in a new group of patients. For the study, injuries were subdivided into malleolar and midfoot zones. Patients who presented to the emergency department with pain or tenderness secondary to blunt ankle trauma due to any mechanism of injury were included. Patients were excluded if they were less than 18 years old, pregnant, has isolated skin injuries, were referred from outside facility with X-rays already completed, if injuries occurred more than 10 days ago, or if the patient had returned for reassessment of the injury.

Participants were evaluated by emergency medicine physicians who recorded their findings and interpretation of the decision rules on a standardized data collection sheet. All patients were then referred for radiography. Images were interpreted by radiologists who were blinded to the findings of the physician in the ED. Clinically significant fractures were defined as bone fragments greater than 3 mm in breadth, as avulsion fractures of 3 mm or less are not treated with plaster immobilization in the institutions involved in the study.

Data collected from the first stage was analyzed in order to refine the decision rules towards the objective of a sensitivity of 1.0. Each of the clinical variables were assessed for association with significant fractures in the ankle and foot radiographs. In the second stage, the sensitivity and specificity of the refined decision rules (see image above) was calculated and the accuracy and reliability of the physicians’ interpretation of the rules was determined. Continue reading

A True Orthopedic and Vascular Emergency

Case: A 76-year-old male presents after falling down a long flight of stairs. On exam the patient has multiple obvious external injuries, including a grossly deformed right shoulder with a large overlying hematoma. His chest x-ray and shoulder x-ray demonstrate a superiorly and laterally displaced right scapula, as well as a comminuted right scapular fracture and clavicle fracture. On further CT imaging, the patient has subtle widening of the scapulothoracic articulation.

OneQuestion: What potentially devastating injury should be considered in this patient?

Continue reading

CITW: Case 2

Two cases this week! Thank you to Dr. David Kaplan for submitting the first case, while the second case was one seen by myself and Dr. Paul Cheung.

Case 1:

58 y/o male sustained blunt force trauma to the lateral aspect of his right knee. On exam, there is a mild right knee effusion, but no obvious deformities. Pain with ROM. Neurovascularly intact. No ligamentous laxity appreciated. X-rays of the right knee are obtained:

Kap Knee

Case 2:

22 y/o male sustained a gunshot wound to the right knee. On exam, there is an entrance wound on the posterior-lateral aspect of the knee, but no exit wound. There is pain with ROM of the knee and a mild effusion is appreciated. No obvious deformities. Neurovasculary intact. No ligamentous laxity appreciated. Initial plain films demonstrate the bullet lodged in the mid-thigh. Physical exam findings and x-rays of the right knee:

Knee

TR Knee

Given concern for an open joint, an aspiration is performed prior to irrigation, and the following aspirate is obtained:

LHA1

What’s the diagnosis?

Continue reading

Canadian Cervical Spine Rules: Moving North a Better Option, Eh?

Main Points:

Screen Shot 2015-08-12 at 2.28.35 PM

                                                                      

1. The final Canadian C-spine Rule comprises three questions:

A.) Is there a high-risk factor that mandates radiography such as: age≥65, dangerous mechanism, or paresthesias in extremities?

B.) Is there any low-risk factor that allows safe assessment of range of motion such as: simple rear end MVC, sitting position in ED, ambulatory at any time since injury, delayed onset of neck pain, or absence of midline C-spine tenderness?

C.) Is the patient able to actively rotate neck 45° to the left and right?

 

  1. The Canadian C-Spine Rule was tested on a convenience sample of 8,924 alert and stable trauma patients in 10 Canadian emergency departments with 151 cases of clinically significant C-spine injury and proved to have a sensitivity of 100% (95% CI: 98-100%) and a specificity of 42.5% (95% CI: 40-44%).

 

Background:

Less than three percent of trauma series yield a positive result.

According to the data compiled by the researchers in the Canadian CT Head and C-Spine Study the use of C-spine radiography is quite variable among emergency physician providers based on local culture and the overall cost of C-spine radiography is in the multi-millions. Their research demonstrated that less than three percent of trauma series yield a positive result. Continue reading

NEXUS Review: Clear That Collar Doc!

Screen Shot 2015-08-02 at 11.56.31 AM

This is the first in a blog series that will explore landmark articles in Emergency Medicine. 

Main Points:

  1. Patients meeting the following five simple clinical criteria are safe to clear without cervical spine imaging following blunt trauma:
    • No focal neurologic deficit
    • Normal alertness
    • No intoxication
    • No midline posterior bony cervical spine tenderness, and
    • No painful distracting injury
  1. The sensitivity and specificity of the NEXUS criteria for detecting low probability injury and avoiding unnecessary imaging was 99 and 12.9 percent respectively, with a negative predictive value of 99.8 percent for the detection of clinically significant injuries.

Level of evidence: 1 (Prospective cohort trial)

Based on the ACEP grading scheme for diagnostic questions the NEXUS trial receives a class of evidence rating of 1.

Background:

Blunt trauma is a frequent cause of emergency department visits. However, the overall prevalence of cervical spine injury is generally only between 2-4% (2.4% in the NEXUS cohort). The goal of the NEXUS group was to create a simple clinical tool with which to risk stratify patients following blunt trauma, thereby reducing unnecessary cervical spine imaging and subsequently improving patient care through cost-reduction and a decrement in the downstream oncogenic risk secondary to radiation exposure. Continue reading