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

Procedural Blog EXTRA: Reduction of TMJ Dislocation

9fabe73c-e43e-47b4-9027-a14138593117_zpsf54998b4a blog series on emergency medicine procedures

Case:

  • 14 year old female presented with inability to close her mouth after yawning.
  • Exam: uncomfortable with jaw open. Limited ROM of jaw bilaterally. Tenderness at TMJ with mandibular displacement bilaterally.

TMJ Dislocation

  • Mandibular condyle moves anteriorly along the articular eminence and becomes locked in place
  • Spasm of the surrounding muscles lead to trismus
  • Condyle cannot return to its normal position

tmj1

From Roberts and Hedges’ Clinical Procedures in Emergency Medicine

Panorex of patient’s bilateral TMJ dislocation:

tmj2

Facial CT 3-D reconstruction showing bilateral TMJ dislocation: 

tmj3 tmj4

Facial CT showing TMJ dislocation: 

tmj5 tmj6

HUNTING & GATHERING

  • Universal precautions (gloves!)
  • Gauze
  • Tongue blade
  • Suction
  • Forceps

PREP

  • Conscious sedation especially in children
  • Massage the masseter muscles in order to relax and fatigue them, which may facilitate manual reduction
  • Consider local anesthesia
    • TMJ space (see below) OR directly into the lateral pterygoid muscle (not discussed)
    • TMJ local anesthesia:
      • Clean the skin anterior to the ear
      • Insert the needle into the TMJ space at the palpable depression caused by the dislocated condyle
      • Direct the needle anteriorly and superiorly onto the inferior surface of the glenoid fossa
      • Inject ~2 mL of local anesthetic (we used lido 1% with epi)

tmj7REDUCTION TECHNIQUES

Consider trying these methods first:

  • Gag technique: Elicit the gag reflex using a tongue blade or cotton swab. During the reflex, inhibition of the muscles of mouth closure permits the mandible to descend, which may free the condyle in some patients. Have suction handy in case of vomiting.
  • Syringe technique: Place a 5 or 10 mL syringe between the posterior upper and lower molars or gums on one of the affected sides. Have the patient gently bite down on the syringe while rolling it back and forth between the teeth until the dislocation on that side is reduced. The opposite side tends to reduce spontaneously. If this does not occur, place the syringe on the opposite side and try the same technique.
    • Note: this requires a high level of participation of the patient (i.e.: will not work in very young children)

If those fail…

  • “Classic Technique”/Intraoral reduction:

  • Have the patient sitting up, facing you, head against the back of the bed
  • Have your arms at the level of the mandible
  • Grasp the mandible with both hands
  • Rest your thumbs on the inside the mouth on the ridge of the mandible adjacent to the molars
  • Wrap thumbs in gauze (leave a trail of gauze outside of the mouth so that it can be easily removed)
  • Wrap your fingers around the outside of the jaw. You may place the thumbs on the occlusal surfaces of the teeth. If you do, keep your thumbs safe from being bitten by wrapping them in gauze
  • Have an assistant hold the head of the patient still.
  • Apply downward pressure to the mandible to free the condyles from the anterior aspect of the eminence, then guide the mandible posteriorly and superiorly back into the temporal fossae.

troubleshooting

You are still having trouble with the reduction:

  • Rock the mandible back and forth to facilitate muscle fatigue
  • Have the patient open the mouth wider while attempting reduction, which will relax the masseter and temporalis muscles

pearl12

Make a head-and-chin bandage after a successful reduction

  • Wrap gauze around the face so that the patient is unable to open their jaw widely while they are sedated/confused to avoid re-dislocation (see below)

tmj8

Image from :http://collections.infocollections.org/ukedu/en/d/Jh2113e/5.2.html

  • Other techniques: Wrist pivot, extraoral reduction, recumbent approach, posterior approach, and ipsilateral approach, which will not be discussed here.

After Discharge

  • Avoid extreme opening of the jaw for 3 weeks.
  • Support the lower jaw when yawning.
  • Soft diet, warm compress, NSAIDs, muscle relaxants.
  • Referral to ENT and/or oral surgery for possible future surgical fixation.

Thank you to Dr. Amir Yavari, Dr. Leslie Sowikowski, Dr. John Diune and the Samuels Sinclair Dental Center for their teaching and allowing us to use this footage. Thank you Dr. Gregory Lockhart, MD and Dr. Michael Prucha, MD for this interesting case. 

 

Authorship

Faculty Reviewer: Gita Pensa

Resident Reviewer: Jonathan Ameli

Author: Chana Rich  

 

Please offer your own tips on TMJ dislocation reductions in the comments section!

References

Riviello, Ralph. Dislocation of the Mandible, Chapter 63, 1298-1341.e1 In: Roberts J, et al. Roberts & Hedges’ Clinical Procedures in Emergency Medicine. 6th Saunders; 2013.

Reyes Mendez, Donna. Reduction of temporomandibular joint (TMJ) dislocation. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on November 17, 2015.)