Ilya Borukhov

Function of the medial meniscus in force transmission and stability.

We studied the combined role of the medial meniscus in distributing load and providing stability. Ten normal knees were loaded in combinations of compressive and shear loading as the knee was flexed over a full range. A digital camera tracked the motion, from which femoral-tibial contacts were determined by computer modelling. Load transmission was determined from the Tekscan for the anterior horn, central body, posterior horn, and the uncovered cartilage in the centre of the meniscus. For the three types of loading; compression only, compression and anterior shear, compression and posterior shear; between 40% and 80% of the total load was transmitted through the meniscus. The overall average was 58%, the remaining 42% being transmitted through the uncovered cartilage. The anterior horn was loaded only up to 30 degrees flexion, but played a role in controlling anterior femoral displacement. The central body was loaded 10-20% which would provide some restraint to medial femoral subluxation. Overall the posterior horn carried the highest percentage of the shear load, especially after 30 degrees flexion when a posterior shear force was applied, where the meniscus was estimated to carry 50% of the shear force. This study added new insights into meniscal function during weight bearing conditions, particularly its role in early flexion, and in transmitting shear forces.

Tibiofemoral contact mechanics following a horizontal cleavage lesion in the posterior horn of the medial meniscus

The purpose of this study was to determine if a horizontal cleavage lesion (HCL) of the posterior horn of the medial meniscus would result in changes to tibiofemoral contact mechanics, as measured by peak contact pressure and contact area, which can lead to cartilage degeneration. To study this, 10 cadaveric knees were tested in a rig where forces were applied (500 N Compression, 100 N shear, 2.5 Nm Torque) and the knee dynamically flexed from −5° to 135°, as peak contact pressure and contact area were recorded. After testing of the intact knee, a horizontal cleavage lesion was created arthroscopically and testing repeated. The Wilcoxon signed‐rank test was used to determine if there were differences in peak contact pressure and contact area between the intact knee and that with the HCL. A statistically significant increase in peak contact pressure of 13%, on average, and a decrease in contact area of 6%, on average, was noted following the HCL. This suggests that a horizontal cleavage lesion will result in small but statistically significant changes in tibiofemoral contact mechanics which may lead to cartilage degeneration.