SLR - March 2019 - Matthew Weber

Preoperative MRI Is Helpful but Not Sufficient to Detect Associated Lesions in Patients with Chronic Ankle Instability

Reference: Staats, K., Sabeti-Ascraf, M., et al. Preoperative MRI is helpful but not sufficient to detect associated lesions in patients with chronic ankle instability. Knee Surg Sports Traumatol Arthrosc. (2018) 26: 2103–2109.

Scientific Literature Review

Reviewed By: Matthew Weber, DPM
Residency Program: Hennepin Healthcare, Minneapolis, MN

Podiatric Relevance: MRI is a commonly used imaging modality to evaluate ankle pathology in cases of chronic ankle instability. While MRI is generally considered to be reliable, lesions may be missed or not always correlate to intraoperative findings. This study explores the reliability of MRI on different ankle pathologies, including osteochondral lesions of the talus.

Methods: MRI images were obtained preoperatively for 30 patients with a mean age of 39.1 ± 15.1 years, with an average symptom duration of 28.4 ± 12.7 months. All patients had histories of chronic ankle sprains, and positive anterior drawer and/or talar tilt tests. These images were evaluated using Outerbridge as well as Berndt and Harty classifications for osteochondral lesions. The MRIs were also evaluated for soft tissue injuries. The images were then compared with arthroscopic intraoperative findings.

Results: Seventy-three injuries/lesions were identified on MRI evaluation. Upon arthroscopy, 72 additional lesions were found. Specifically for cartilage lesions, sensitivity was 91 percent and specificity was 55 percent for the Outerbridge grading scale. For the Berndt and Harty classification system, sensitivity and specificity were 91 percent and 28 percent, respectively.

Conclusion: Chronic ankle instability is associated with a variety of pathology, and MRI is incompletely effective at revealing all of these lesions. While MRI is a valuable tool for evaluation, use of arthroscopy should be considered the definitive modality for assessment of additional pathology.

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