Femoral articulating surface

A normal adult human knee contains two menisci - the lateral and the medial, whose average lengths are 38 and 45 mm, and average volumes are 2.9 and 3.45 cm respectively [4]. At the femoral articulating surface... 

We have thus far been concerned primarily with wear at the articulating surface between the femoral condyles and UHMWPE tibial insert. However, recently, researchers have drawn attention to backside articulation (i.e., between the tibial insert and the metallic tray or baseplate) as potentially a clinically relevant source of wear debris (Engh et al. 2001, O Rourke et al. 2002, Wasielewski et al. 1997). Relative motion between the UHMWPE insert and metallic tray is resisted by the locking mechanism. These mechanisms are proprietary and design specific. Consequently, it is difficult to generalize about the integrity of locking mechanisms and propensity for backside wear. 

The femoropatellar joint is a sellar joint the articulating surface of the patella is adapted to the patellar surface of the femur. This femoral articulation involves the anterior surface of both condyles. An oblique groove divides it into a large lateral and smaller medial area. The quadriceps muscles, the quadriceps tendon, and the patellar tendon maintain the joint s stability. Its major motions are vertical up-and-down movement on the femur, and movement in a sagittal plane with respect to the tibia. This allows a pulley function during flexion and extension of the knee. 

Davidson JA, Schwartz G. Wear, creep and frictional heat of femoral implant articulating surfaces and the effect on long-term performance-Part 1, a review. J Blamed Mater Res 1987 21 261-85. 

UHMWPE is used as an articulating surface in both hip and knee joint replacements. As an acetabular component in THR (total hip replacement), its annual wear rate was reported to be approximately 0.1 mm/ year or 80 mmVyear against a 32 mm diameter femoral head. Hall et al. [70], and Oonishi et al. [71]. It is approximately a 30-fold reduction in wear rate in comparison with a PTFE socket that was first introduced by... 

The femoral component is composed of the head, neck, coUar, and stem (see Eig. 11). The head, or ball, is the surface component which articulates... 

Despite brittle characteristics, ceramic components enjoy several outstanding tribological properties, including their hardness (Table 6.2), which contributes to wear resistance and scratch resistance. Ceramic surfaces are also more hydrophilic than the CoCr surfaces of a femoral head, as illustrated in Figure 6.7 by the water droplets. The improved wettability of ceramics contributes to lower friction than CoCr when articulated against UHMWPE under physiologic loading and lubrication conditions (Morlock et al. 2002). 

The hip joint joins the pelvis to the lower extremity. It is a ball-and-socket articulation that allows motion in three planes and circumduction. Its bony components are the acetabulum, which is at the junction of the ilium, ischium, and pubic bones and the head of the femur. The convex femoral head fits into the concave acetabulum. The articular surfaces are reciprocally curved but are not coextensive, nor are they fully congruent. The close-packed position of the hip joint is fuU extension, abduction, and medial rotation. 

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