Imaging of the medial collateral ligament of the knee: a systematic review

Abstract

Introduction The primary aim of this investigation was to systematically review relevant literature of various imaging modalities (magnetic resonance imaging (MRI), stress radiography and ultrasonography) in the assessment of patients with a medial collateral ligament (MCL) injury. Materials and methods A systematic literature review of articles indexed in PubMed and Cochrane library was performed. Original research reporting data associated with medial gapping, surgical, and clinical findings associated with MCL injuries were considered for inclusion. The methodological quality of each inclusion was also assessed using a verified tool. Results Twenty-three imaging studies (magnetic resonance imaging (MRI) n = 14; ultrasonography n = 6; radiography n = 3) were ultimately included into the review. A total of 808 injured, and 294 control, knees were assessed. Interobserver reliabilities were reported in radiographic and ultrasonographic investigations with almost perfect agreement. MRI studies demonstrated agreement ranging between substantial to almost perfect. Intraobserver reliability was only reported in radiographic studies pertinent to medial gapping and was found to be almost perfect. Correlation of MRI with clinical findings was moderate to strong (65–92%). Additionally, MRI imaging was more sensitive in the detection of MCL lesions when compared to clinical examination. However, when compared to surgical findings, MRI underestimated the grade of instability in up to 21% of cases. Furthermore, MRI showed relatively inferior performance in the identification of the exact MCL-lesion location when compared to surgical findings. Interestingly, preoperative clinical examination was slightly inferior to stress radiography in the detection of MCL lesions. However, clinical testing under general anaesthesia performed similar to stress radiography. The methodological quality analysis showed a low risk of bias regarding patient selection and index testing in each imaging modality. Conclusion MRI can reliably diagnose an MCL lesion but demonstrates limitations in its ability to predict the specific lesion location or grade of MCL instability. Ultrasonography is a widely available, radiation free modality, but is rarely used in clinical practice for detecting MCL lesions and clinical or surgical correlates are scarce. Stress radiography findings correlate with surgical findings but clinical correlations are missing in the literature. Level of evidence IV.

Comparing the findings of clinical examination versus magnetic resonance imaging for the diagnosis of ligamentous injuries of knee in rural area

“…Study by Meyer et al found that interestingly, preoperative clinical examination was slightly inferior to stress radiography in the detection of MCL lesions. 6 However, clinical testing under general anaesthesia performed similar to stress radiography. The methodological quality analysis showed a low risk of bias regarding patient selection and index testing in each imaging modality.…”

The medial knee gap measured on ultrasound images is wider during a valgus stress test compared to the anterior medial knee rotation test

“…This increased widening of the medial knee joint gap has been found in studies using x-ray and ultrasound imaging techniques. 5,14 The results of the cadaver and finite element studies suggest that injury of the dMCL or POL structures should result in greater widening of the medial joint gap during the ANTMED rotational stress test. 7,[15][16][17] Improved understanding of the clinical tests for the assessment of knee ANTMED rotational stability will lead to earlier recognition of injury to the dMCL and POL and will likely lead to improved outcomes for patients with ANTMED rotational knee instability.…”

Dynamic Ultrasound Can Accurately Quantify Severity of Medial Knee Injury: A Cadaveric Study

“…Moreover, the accuracy of this test in quantifying MCL injuries is highly susceptible to the examiner's subjective interpretation and has proven to be unreliable, especially in an acute setting. 15 Diagnostic confirmation has thus often relied on provocative stress maneuvers under imaging. 15,16 The current gold standard modality for evaluating medial knee injury is magnetic resonance imaging (MRI); however, because medial knee instability is a dynamic process, assessing the appearance of the medial knee ligaments on static MRI can result in high false-negative rates.…”

“…15 Diagnostic confirmation has thus often relied on provocative stress maneuvers under imaging. 15,16 The current gold standard modality for evaluating medial knee injury is magnetic resonance imaging (MRI); however, because medial knee instability is a dynamic process, assessing the appearance of the medial knee ligaments on static MRI can result in high false-negative rates. 8,15 Furthermore, it does not allow for a comparison with the contralateral healthy side.…”

“…15,16 The current gold standard modality for evaluating medial knee injury is magnetic resonance imaging (MRI); however, because medial knee instability is a dynamic process, assessing the appearance of the medial knee ligaments on static MRI can result in high false-negative rates. 8,15 Furthermore, it does not allow for a comparison with the contralateral healthy side. Radiographs preferably with stress maneuvers such as valgus stress test routinely have been used to evaluate the competence of the medial knee ligaments due to their widespread use and ability to provide a contralateral comparison.…”