Dynamic contact mechanics on the tibial plateau of the human knee during activities of daily living

Abstract

Despite significant advances in scaffold design, manufacture, and development, it remains unclear what forces these scaffolds must withstand when implanted into the heavily loaded environment of the knee joint. The objective of this study was to fully quantify the dynamic contact mechanics across the tibial plateau of the human knee joint during gait and stair climbing. Our model consisted of a modified Stanmore knee simulator (to apply multi-directional dynamic forces), a two-camera motion capture system (to record joint kinematics), an electronic sensor (to record contact stresses on the tibial plateau), and a suite of post-processing algorithms. During gait, peak contact stresses on the medial plateau occurred in areas of cartilage-cartilage contact; while during stair climb, peak contact stresses were located in the posterior aspect of the plateau, under the meniscus. On the lateral plateau, during gait and in early stair-climb, peak contact stresses occurred under the meniscus, while in late stair-climb, peak contact stresses were experienced in the zone of cartilage-cartilage contact. At 45% of the gait cycle, and 20% and 48% of the stair-climb cycle, peak stresses were simultaneously experienced on both the medial and lateral compartment, suggesting that these phases of loading warrant particular consideration in any simulation intended to evaluate scaffold performance. Our study suggests that in order to design a scaffold capable of restoring ‘normal’ contact mechanics to the injured knees, the mechanics of the intended site of implantation should be taken into account in any pre-clinical testing regime.

Altered regional loading patterns on articular cartilage following meniscectomy are not fully restored by autograft meniscal transplantation

“…This disrupted loading could endanger the cartilage in the adjacent regions where again, the cartilage is thinner 30, 31 and considered not to be conditioned to withstand such high loads. 17 In addition to the changes in the affected medial compartment, we also found accompanying changes in the lateral compartment, where pattern-2 shifted anterior-laterally. This may be due to the increased joint rotational laxity associated with meniscal deficiency.…”

“…1B). 15–17 Contact stresses normal to the tibial plateau surface were recorded in real-time (100 Hz) using a thin electronic sensor (model: 4010N, Tekscan Inc., MA), Fig. 1C, which was inserted under both menisci of the medial and lateral plateau.…”

Development of a Cartilage Shear-Damage Model to Investigate the Impact of Surface Injury on Chondrocytes and Extracellular Matrix Wear

“…The loading pressure is akin to contact forces seen in vivo during walking. [25][26][27] The creation of a migrating contact point in the model further allows for improved lubrication 28 and for greater cell viability. 29 For tribological testing, strips and balls were mounted onto the joint motion simulator with their corresponding discs.…”

Establishing a live cartilage-on-cartilage interface for tribological testing

“…Further, the applied load of 45N results in a contact stress in excess of 2 MPa to the cartilage discs, in rage with in vivo findings[40]. Physiological loads experienced by cartilage at the hip[57,58] or knee[59] have been measured to be about 1 MPa during standing with peaks of 5 – 10 MPa during walking. It is also important to note that MoC models have been shown to experience higher contact stresses and frictional forces[19,56], as well as higher impact stress[16], when compared to CoC models.…”