How To Diagnose Lateral Ankle Injuries

Start Page: 65

Continuing Education Course #135 — October 2005

I am pleased to introduce the latest article, “How To Diagnose Lateral Ankle Injuries,” in our CE series. This series, brought to you by the North American Center for Continuing Medical Education (NACCME), consists of regular CE activities that qualify for one continuing education contact hour (.1 CEU). Readers will not be required to pay a processing fee for this course.

Diagnosing a lateral ankle injury can be challenging. The initial presentation may be deceptive and some injuries may require more advanced imaging to confirm an accurate diagnosis. Addressing these and other key points, Remy Ardizzone, DPM, and Ronald L. Valmassy, DPM, provide a comprehensive guide to these common injuries that range from chronic lateral ankle instability to peroneal tendon injuries.

At the end of this article, you’ll find a 10-question exam. Please mark your responses on the enclosed postcard and return it to NACCME. This course will be posted on Podiatry Today’s Web site (www.podiatrytoday.com) roughly one month after the publication date. I hope this CE series contributes to your clinical skills.

Sincerely,

Jeff A. Hall
Executive Editor
Podiatry Today

INSTRUCTIONS: Physicians may receive one continuing education contact hour (.1 CEU) by reading the article on pg. 66 and successfully answering the questions on pg. 74. Use the enclosed card provided to submit your answers or log on to www.podiatrytoday.com and respond via fax to (610) 560-0502.
ACCREDITATION: NACCME is approved by the Council on Podiatric Medical Education as a sponsor of continuing education in podiatric medicine.
DESIGNATION: This activity is approved for 1 continuing education contact hour or .1 CEU.
DISCLOSURE POLICY: All faculty participating in Continuing Education programs sponsored by NACCME are expected to disclose to the audience any real or apparent conflicts of interest related to the content of their presentation.
DISCLOSURE STATEMENTS: Drs. Ardizzone and Valmassy have disclosed that they have no significant financial relationship with any organization that could be perceived as a real or apparent conflict of interest in the context of the subject of their presentation.
GRADING: Answers to the CE exam will be graded by NACCME. Within 60 days, you will be advised that you have passed or failed the exam. A score of 70 percent or above will comprise a passing grade. A certificate will be awarded to participants who successfully complete the exam.
TARGET AUDIENCE: Podiatrists.
RELEASE DATE: October 2005.
EXPIRATION DATE: October 31, 2006.
LEARNING OBJECTIVES: At the conclusion of this activity, participants should be able to:
• differentiate among grade 1, grade 2 and grade 3 injuries to the lateral collateral ligaments;
• discuss common physical examination findings with chronic lateral ankle instability;
• assess findings from talar tilt and anterior drawer tests;
• discuss contributing factors to peroneal tendon injuries; and
• assess the potential benefits of orthotics as an adjunctive treatment for lateral ankle sprains.

Sponsored by the North American Center for Continuing Medical Education.

Here one can see an acute ankle injury. Once one has ruled out a fracture, acute or chronic lateral ankle injuries represent a diagnostic challenge.
This manual talar tilt/inversion stress radiograph shows excessive talar inversion within the ankle mortise. Note the intraarticular loose body in the lateral gutter.
This manual anterior drawer stress radiograph demonstrates incompetence of the anterior talofibular ligament.
Here one can see a peroneal tenogram showing extensive stenosing tenosynovitis and adhesions.
On this T1-weighted MRI image, one can see a partial tear to the anterior talofibular ligament and a shallow fibular groove.
Here is an extensive talar osteochondral defect on a T1-weighted MRI sequence.
Here one can see a compensated rigid forefoot valgus with an inverted calcaneus.
74
Author(s): 
By Remy Ardizzone, DPM, and Ronald L. Valmassy, DPM

   The anterior drawer test consists of manipulating the affected ankle while taking a lateral X-ray view. To perform this test, it is important for the patient to lie partially on the affected side in such a manner as to obtain as true a lateral projection of the ankle as possible. The fibula should be slightly posterior to the line of the X-ray beam, mimicking its anatomic position. Placing the ankle in 10 degrees of plantarflexion improves the sensitivity of the test.14 One should perform an anterior displacement test on the talus by cupping the calcaneus and pulling forward and slightly downward with one hand while stabilizing the tibia with the other hand. There are various methods of measuring this test but typically the test is considered positive when there is a 10 mm excursion of the talus from under the tibia or 3 mm more than the contralateral side.15 Recent studies suggest that measuring the posterior excursion of the tibia from the posterior aspect of the talus may produce more reliable and reproducible measurements.16

   These tests also provide insight into which ligaments may be injured. An anterior drawer test indicates injury to the anterior talofibular ligament but does not necessarily exclude injury to the calcaneofibular ligament. The talar tilt test isolates injury to the calcaneofibular ligament.9

   While magnetic resonance imaging (MRI) may offer valuable information for an elite or professional athlete in the setting of an acute ankle sprain, it has little to offer when it comes to establishing a diagnosis of chronic instability. This requires dynamic testing such as the anterior drawer and talar tilt stress X-rays.17,18

Recognizing Cases Of Functional Instability

   Additionally, a subset of patients may have negative stress exams but still demonstrate frequent minor inversion industries and a sense of instability to the ankle. This condition describes functional instability as opposed to mechanical instability.5,8,19,20 Under these circumstances, the ligaments may only have healed in a somewhat slightly loosened position but the patient has failed to re-establish the proprioceptive connection to the brain.21 Proprioceptive fibers are embedded within the lateral collateral ankle ligaments and sustain injury along with the ligament itself.8,21,22

   One may assess proprioception in these patients by using a modified Rhomberg test. The patient stands on the normal ankle with his or her eyes open and then closed. Repeat this procedure on the symptomatic limb. Alternatively, the patient may rise onto the ball of the affected foot and perform five single leg hops.5-8 One of the key components of physical therapy is to reestablish these proprioceptive connections so the patient senses uneven surfaces and can recruit other muscles to stabilize the ankle and avoid inversion injury.23,24

   Other contributors to functional instability include impaired joint position sense, delayed peroneal muscle reaction time, altered common peroneal nerve function and muscle weakness.5,8

Pearls For Diagnosing Peroneal Tendon Injuries

   Injury to the peroneal tendons can manifest in several ways, including peroneal tendon tears, tenosynovitis and subluxation. During an inversion injury, the peroneus brevis and peroneus longus tendons fire in an attempt to evert the foot forcibly, thereby stabilizing the ankle to prevent it from inverting.25 This can result in a subtle, longitudinal tear to one of the tendons. The peroneus brevis tendon is commonly injured given its close proximity to the posterolateral tip of the fibula.26

image description image description


Post new comment

  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.

More information about formatting options

Image CAPTCHA
Enter the characters shown in the image.