Fig. 3

Medial meniscus displacement during passive motion. A Schematic view of the insertion device and procedure of insertion of the beads into the meniscus. Beads were placed in the insertion needle, and the needle was again placed into a device that secured an insertion depth of 10 mm in the meniscal stroma through the knee joint capsule. Then, three beads of 0.8 mm diameter were inserted under arthroscopic control. B Knee-joint loading apparatus. On the left side, the femur (f), which is rigidly fixated in the semi-lunar device. Different knee-joint flexion angles are realized rotating the semi-lunar device thereby changing the angle of the femur relative to the tibia, as indicated in (a). The axial load (b) is applied to the femur. On the right side, the tibia (t). On this side of the apparatus, freedom of movements are internal and external rotation, varus–valgus rotation, ML translation and AP translation. Internal and external torques (d) were applied through a pair of sheaves (c). C Positioning of the loading apparatus, the Roentgen tubes, and the film cassette. Two separate X-rays were taken with two tubes on the same Roentgen film. Note the reference points on the film cassette and the positioning of the knee joint in the coordinate system: the X-direction represents ML displacements on the tibial plateau and the Z-direction represents the AP displacement on the tibial plateau. From “Displacement of the medial meniscus within the passive motion characteristics of the human knee joint: an RSA study in human cadaver knees.” by Tienen TG et al., 2004, Knee Surg Sports Traumatol Arthrosc. 2005;13(4):287-92 [17]. With permission of Springer