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

   Chronic ankle instability has a higher incidence of osteochondral lesions than acute distal fibular fracture.43 The patient may complain of periodic “clicking,” “popping” or “locking” of the ankle. Frequently, these occurrences are random. There may be persistent pain to the anterolateral ankle that often occurs with end-range dorsiflexion, especially with impact activities or walking uphill. Patients often describe the pain as a dull, aching sensation about the ankle joint.3,44

   Chondral and osteochondral lesions typically involve the posterior medial and anterior lateral aspects of the talus.45,46 Posterior medial lesions frequently are less symptomatic and not always associated with trauma. Anterior lateral lesions are associated with trauma in nearly 100 percent of cases.44-47 One should maintain a high index of suspicion in patients who have persistent pain despite normal radiographs or those who fail to improve after traditional treatment following a routine ankle sprain.

   Physical examination may reveal persistent focal swelling to the anterior lateral ankle with pain to palpation of this area, particularly with the ankle in plantarflexion. Crepitus may be present and pain may increase with tibial talar compression. The presence of an intraarticular loose body may precipitate locking. In late stages, the presentation will be consistent with an arthritic joint.

   Although some osteochondral lesions may be visible on plain radiographs, which provide the basis for the Berndt-Hardy classification, a MRI provides more specific evidence of pathology.45 Various sequences highlight different tissues, contrast and spatial resolution. Fat-suppressed proton density-weighted or T2-weighted sequences (STIRs) are often the most sensitive for detecting contusion or trabecular injury to the underlying bone.3 Bone marrow edema adjacent to chondral defect generally indicates that the lesion is active or likely symptomatic. One may use MRI to help assess and track healing of lesions over time.

   Impingement syndromes generally result from hyalinized fibriolysis of the hemarthrosis associated with lateral ankle ligament injury, leading to posttraumatic synovitis within the anterolateral gutter.48,49 This inflamed scar tissue, which may be triangular or meniscoid in shape, impinges on the anterolateral margin of the talar dome, causing pain and decreased range of motion.20,50 Over time, this may cause repetitive abrasion of the chondral surface and erosion of the articular cartilage.

   In impingement syndromes, the clinical examination may reveal chronic edema to the anterolateral ankle in the location of the anterior talofibular ligament. There is pain to palpation in this region or one may only produce pain with provocation such as closed chain dorsiflexion of the ankle. There may be resistance to attempted rotary motion of the ankle as well as decreased ankle joint dorsiflexion compared to the contralateral side.

   Plain X-rays may reveal the presence of an osseus intraarticular loose body. Whether this is present or not, obtaining a MRI will help determine the location of the loose body and can also detect excessive scar tissue or meniscoid bodies that may be limiting joint motion and contributing to persistent painful synovitis.3

Assessing The Potential Impact Of Orthotic Solutions

   Given that a significant percentage of chronic lateral ankle problems is associated with either a flexible or rigid forefoot valgus deformity, functional foot orthoses offer an effective adjunct to the overall management of this condition.

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