How To Diagnose Lateral Ankle Injuries

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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

   Without physical therapy, the ligaments will heal in a “stretched out” or loosened position that contributes to instability. Employing U-shaped padding about the lateral malleolus in combination with compression promptly after the injury can minimize the swelling. It is the persistent swelling about the ligaments that helps maintain the stretched out position. Using an ankle stabilizer brace will help support the ligaments while allowing normal ankle function and alignment. Physical therapy not only helps patients regain full strength but also facilitates proprioception, which is essential in preventing instability.

   While the ankle sprain is a common injury, chronic lateral ankle instability typically requires a history of recurrent inversion sprains. Patients will often complain that the affected ankle feels “unstable” or “gives out” frequently. They typically feel unsteady when walking on uneven ground or sloped surfaces. Repeat inversion injuries will occur with the slightest provocation. Not uncommonly, these patients report twisting or spraining their ankles every few months with varying levels of severity.7,12 Bracing or taping may not provide adequate stability.

   Clinically, physical examination findings commonly reveal persistent swelling to the anterolateral aspect of the ankle, even if there has been no recent re-injury. There may or may not be tenderness to palpation of the anterior talofibular ligament or calcaneofibular ligament. Typically, one will see a positive anterior drawer sign or anterior displacement of the talus from the tibia, similar to what clinicians would see with an acute ankle injury. There is also increased inversion of the talus in the ankle mortise, particularly when one compares this to the contralateral ankle. When there is attempted rotary motion of the ankle within the mortise, the talus will often translocate laterally.

How To Perform And Assess Talar Tilt And Anterior Drawer Tests

   Specific diagnostic tests are required to definitely diagnose instability. Most practitioners perform manual stress X-rays of the ankle. Like most manual tests, accuracy and reproducibility depend on the skill of the practitioner. One can reduce this variability by using a stress device machine, which exerts a constant pressure of 15 kPa in an attempt to displace the talus within the ankle mortise. However, access to such equipment is limited. In either case, the specific diagnostic tests consist of talar inversion stress (talar tilt) and anterior displacement stress (anterior drawer). In most cases, one should apply both tests to the symptomatic as well as the asymptomatic ankle.

   Originally described by Farber in 1932, the talar tilt test refers to the angle formed during forceful inversion of the hindfoot between the talar dome and tibial plafond. One may perform this test by cupping the patient’s calcaneus in one’s hand, keeping the thumb clear of the ankle joint, and stabilizing the tibia with the other hand. Then the clinician would invert the calcaneus and talus as far as possible given the patient’s tolerance. The practitioner holds this position while an AP X-ray is taken. If the patient resists movement in any way, then it may be necessary to administer a local anesthetic block to the ankle. Typically, this is not necessary with manual exams but is often required when using a stress device machine. Exact measurements vary but generally the test is considered positive when the angle of talar tilt measures greater than 18 degrees or differs from the contralateral side by more than 5 degrees.7,13

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