ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

Fig. 3: Pressure distribution in the medial and lateral tibial plateau articular cartilage
obtained from (a) in vitro cadaver experiment and (b) finite element study
Table 2: Forces and peak pressures obtained from in vitro and finite element studies for
the medial and lateral compartments of the tibio femoral joint. * Percentage
difference in ratio of medial to lateral force between in vitro experiment and
Peak lateral
pressure
(MPa)
FE model.
Peak medial
pressure
(MPa)
Total lateral
force (N, % of
total force)
Total medial
force (N, %of
total force)
In Vitro 0.09 2.33 6.04, 2 308, 98
FE Model 0.59 2.44 9.9, 3.5 267, 96.5
% Difference 496 4.7 1.5* 1.5*
3.3.5 Modelling of Meniscectomy
For both the simulated intact and meniscectomised knees, the proximal ends of the tibia
and fibula were mechanically grounded. An axial compressive load of 800 N was
applied at the distal end of the femur with the knee flexed at 20 degrees simulating the
weight acceptance portion of the stance phase of gait.
4. RESULTS
Figure 4 illustrates the stress distribution in the medial and lateral tibial cartilage and
meniscus when an axial load of 800 N was applied to the simulated intact and
meniscectomised knees. The meniscus of the simulated intact knee transmitted 70% of
the total axial load. The peak pressure value in the tibial cartilage was higher in the
medial compartment for the intact knee, as shown in Table 3. Following simulated
meniscectomy, peak pressures in the medial and lateral tibial cartilage increased by 39%
and 105%, respectively.
a b
Fig. 4: Stress distribution for (a) an intact and (b) meniscectomised knee