Furthermore, in the present study the type of articulation did not significantly affect the survival rate of the stem.
The magnitude of the forces that are physiologically applied to cartilage is up to 20 MPa, according to the type of articulation, movement and weight of the individual [ 2].
Compared with 212 800 conventional replacements with a proximally non-modular neck (five and 10 year survival 3.7% (3.6 to 3.8) and 6.4% (6.3 to 6.6)), the revision risk was, irrespective of the type of articulation used, roughly doubled after correction for age and sex (10 year period hazard ratio 1.92 (1.76 to 2.10)).
This article addresses the engineering aspects concerning the advantages and disadvantages of each type of articulation.
It had (1) teeth set in grooves, not sockets, (2) a stout fourth toe with a unique rotary ball-and-flange type of articulation, and (3) tail (caudal) vertebrae with limited vertical motion, making the tail somewhat beaverlike in its action.
Wear mechanisms are discussed as a function of contact stresses, lubricants and clearance, surface hardness and roughness, type of articulation due to motion, number of cycles, solution particle count and distribution, oxidation of materials, and surface abrasions of both metal and polyethylene particulates.
The wear mechanisms in biomedical implants, particularly hip joints, are reported to be a function of the following variables: type of materials used, contact stresses, lubricants and clearance, surface hardness and roughness, type of articulation due to motion, number of cycles, solution particle count and distribution, and tribocorrosion.
The acetabular component and type of articulation are chosen according to the preferences of the surgeon.
In another retrieval study looking at 90 modular implants, corrosion damage of the trunnion varied with type of articulation and head size [ 57].
The type of articulation (either ceramic-on-polyethylene or 28-mm metal-on-metal), age, varus/valgus malpositioning, or undersizing of the femoral component did not significantly affect survival with stem loosening or stem revision for any reason as the endpoint (Table 4).
