SLR - August 2017 - Stephanie P. Means
Reference: Jae Ho Cho, Doo Hyung Lee, Hyung Keun Song, Joon Young Bang, Kyung Tai Lee, Young Uk Park. Value of Stress Ultrasound for the Diagnosis of Chronic Ankle Instability Compared to Manual Anterior Drawer Test, Stress Radiography, Magnetic Resonance Imaging and Arthroscopy. Knee Surg Sports Traumatol Arthrosc (2016) 24:1022–1028.Scientific Literature Review
Reviewed By: Stephanie P. Means, DPM
Residency: Hennepin County Medical Center, Minneapolis, MN
Podiatric Relevance: As foot and ankle surgeons, we often encounter and treat patients with chronic lateral ankle instability. This article looks at the value of stress ultrasound, an easy in-office exam, as a method for determining extent of damage to the anterior talofibular ligament (ATFL), as well as comparing reliability to manual testing, stress radiography and MRI. Should this be proven to be an effective method for lateral ankle instability evaluation, it would provide foot and ankle surgeons with an additional in-office exam for evaluation of and treatment guidance for ATFL damage.
Methods: The authors of this study retrospectively reviewed 28 patients with a mean age of 32.4 who underwent ankle arthroscopy and subsequent modified Broström repair for chronic ankle instability between 2013 and 2014. All procedures were performed by one qualified surgeon, and all patients underwent manual anterior drawer testing, stress radiography, magnetic resonance imaging and stress ultrasound to evaluate ATFL prior to procedure. Arthroscopy was performed to confirm the diagnosis and to serve as the reference standard for evaluation of the above examinations. The ATFL length was measured during ultrasound examination with both stress applied to the lateral ankle as well as at rest. These measurements were used to determine presence as well as severity of ATFL damage. The results of this exam were then directly compared to the MRI, manual anterior drawer, stress radiographs and arthroscopic findings.
Results: All 28 patients had confirmed Grade 3 lateral instability arthroscopically. Of these, 78.6 percent had a positive anterior drawer test, 97 percent displayed either anterior translation greater than 5 mm on stress radiography or a talar tilt angle greater than 15 degrees (indicative of injury to ATFL), 100 percent displayed a change in thickness or signal intensity of ATFL on MRI and 100 percent displayed a lax and wavy ATFL on stress ultrasound. On average, there was a difference of 0.7 cm in length of ATFL when resting versus stressed.
Conclusions: Stress ultrasound is a valuable adjunctive in-office, noninvasive exam to consider for diagnosis of ATLF injury. A change in measured length greater than 20 percent between resting and stressed images may serve as a cutoff for diagnosis.