Correlation between magnetic resonance imaging and surgical exploration of the anterolateral structures of the acutely anterior cruciate ligament injured knee

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Monaco, E., Partezani Helito, C., Redler, A., De Carli, A., Argento, G., Partezani Helito, P.V., Saithna, A. ORCID: 0000-0002-2408-5307 and Ferretti, A., 2019. Correlation between magnetic resonance imaging and surgical exploration of the anterolateral structures of the acutely anterior cruciate ligament injured knee. The American Journal of Sports Medicine, 47 (5), pp. 1186-1193. ISSN 0363-5465

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Official URL: https://doi.org/10.1177/0363546519831686

Abstract

Background: Combined Anterior Cruciate Ligament (ACL) and Anterolateral ligament (ALL) reconstruction is associated with improved clinical outcomes compared to isolated intra-articular reconstruction but the indications are not precisely defined. It may be the case that patients with proven anterolateral injury on pre-operative imaging are most likely to benefit but the accuracy of MRI is not known.

Hypothesis/Purpose: To evaluate the correlation between MRI findings and intra-operative anterolateral compartment exploration in acute ACL injured knees. The study hypothesis was that a positive correlation would be identified between imaging and surgical findings for injuries to the ALL/capsule and the iliotibial band and that pre-operative MRI would be associated with high sensitivity, specificity and accuracy for these parameters.

Study Design: Case Series.

Methods: Between January 2016 to May 2016 patients presenting with an acute ACL injury were considered for study eligibility. A sample size calculation determined the numbers enrolled. Included patients underwent 1.5T MRI and this was evaluated by three investigators who attributed a Ferretti grade of injury to the anterolateral structures. At the time of ACL reconstruction, a lateral exploration was undertaken and macroscopic injuries were identified, classified and repaired. An evaluation of correlation between MRI and surgical exploration findings was performed.

Results: 26 patients participated in the study. 96% had an ALL/capsule injury. The sensitivity, specificity and accuracy of MRI in the evaluation of ALL/capsule injury, when using surgical exploration as a gold standard were 88%, 100% and 88.5% respectively. For evaluation of iliotibial band injury these values were 62.5%, 40% and 50%. The percentage agreement between MRI and surgical findings for ALL/capsule injury was 88% but only 65% for the ITB. The sensitivity and specificity of MRI for complete or partial tear of ALL and capsule were 78.6 and 41.7 respectively. The k test for correlation between surgical and MRI findigs was 0.27 for ITB abnormalities, 0.47 for ALL/capsule abnormalities, 0.23 for ALL/capsule determination of partial or complete tear and 0.49 for ALL/capsule determination of anterior or posterior tear. The overall percentage agreement between MRI and the classification based on surgical findings was only 53% and the Altman classification of kappa was fair. This suggests that whilst the classification is useful for description of surgical findings the grade cannot be reliably established from MRI, at least with the parameters used in the current study.
Conclusion: Surgical exploration demonstrates that injuries occur to the anterolateral structures in almost all acute ACL injured knees. Pre-operative MRI is highly sensitive, specific and accurate, for detection of abnormalities of the ALL/capsule and shows a high percentage of agreement with surgical findings. In contrast MRI has low sensitivity, specificity, and accuracy for the diagnosis of ITB injury. The agreement between MRI and surgical exploration with respect to ITB abnormality and determination of whether ALL/capsular tears were partial or complete was only fair.

Item Type:

Journal article

Publication Title:

The American Journal of Sports Medicine

Creators:

Monaco, E., Partezani Helito, C., Redler, A., De Carli, A., Argento, G., Partezani Helito, P.V., Saithna, A. and Ferretti, A.

Publisher:

SAGE in association with the American Orthopaedic Society for Sports Medicine

Date:

2019

Volume:

Number: