Assessment of the Relationship between the Shape of the Lateral Meniscus and the Risk of Extrusion Based on MRI Examination of the Knee Joint

<div><p>Background</p><p>Meniscus extrusion is a serious and relatively frequent clinical problem. For this reason the role of different risk factors for this pathology is still the subject of debate. The goal of this study was to verify the results of previous theoretical work, based on the mathematical models, regarding a relationship between the cross-section shape of the meniscus and the risk of its extrusion.</p><p>Materials and Methods</p><p>Knee MRI examination was performed in 77 subjects (43 men and 34 women), mean age 34.99 years (range: 18–49 years), complaining of knee pain. Patients with osteoarthritic changes (grade 3 and 4 to Kellgren classification), varus or valgus deformity and past injuries of the knee were excluded from the study. A 3-Tesla MR device was used to study the relationship between the shape of the lateral meniscus (using slope angle, meniscus-cartilage height and meniscus-bone angle) and the risk of extrusion.</p><p>Results</p><p>Analysis revealed that with values of slope angle and meniscus-bone angle increasing by one degree, the risk of meniscus extrusion raises by 1.157 and 1.078 respectively. Also, an increase in meniscus-cartilage height by 1 mm significantly elevates the risk of extrusion. At the same time it was demonstrated that for meniscus-bone angle values over 42 degrees and slope angle over 37 degrees the risk of extrusion increases significantly.</p><p>Conclusions</p><p>This was the first study to demonstrate a tight correlation between slope angle, meniscus-bone angle and meniscus-cartilage height values in the assessment of the risk of lateral meniscus extrusion. Insertion of the above parameters to the radiological assessment of the knee joint allows identification of patients characterized by an elevated risk of development of this pathology.</p></div

Meniscal extrusion is defined as the greatest distance (line No 3) from the most peripheral aspect of the meniscus (line No 2) to the border of the tibial plateau (line No 1).

<p>Meniscal extrusion is defined as the greatest distance (line No 3) from the most peripheral aspect of the meniscus (line No 2) to the border of the tibial plateau (line No 1).</p

Logistic regression results—model 2.

<p>Logistic regression results—model 2.</p

ROC and cut off point for Slope angle.

<p>ROC—receiver operating characteristic.</p

ROC analysis results for MBA and Slope angle.

<p>ROC analysis results for MBA and Slope angle.</p

Test results for difference between the groups NE and E.

<p>Test results for difference between the groups NE and E.</p

Survival Function for Slope angle.

<p>Survival Function for Slope angle.</p

Survival Function for MBA.

<p>MBA—meniscus-bone angle.</p

Assessment of the Relationship between the Shape of the Lateral Meniscus and the Risk of Extrusion Based on MRI Examination of the Knee Joint - Fig 2

<p>A-E. The central slice of a coronal MRI imaging of the knee focused on lateral compartment: A) meniscus-bone angle, B) meniscus-cartilage angle, C) meniscus-cartilage height, D) slope A, E) slope angle.</p