Which femoral neck for a dual mobility cup? A biomechanical evaluation.

Purpose: This study aimed to evaluate polyethylene (PE) damage and wear lesions to the chamfer of mobile components under mobile and fixed femoral neck impingement at the third articulation, and to determine which femoral neck characteristics should be considered with a dual mobility cup to limit those lesions.

Methods: Two femoral neck geometries (cylindrical and quadrangular) with two surface finishing roughness (rough and polished), and two head-to-neck ratios (28- and 22.2-mm diameter femoral heads) were evaluated in a hip simulator testing.

Effects of corrosion and cleaning method on taper dimensions: an investigation.

Purpose: Taper corrosion related revisions have recently been reported in the orthopaedic literature. Cleaning procedure of the trunnions during hip revision is not standardised. The purpose of this bench top investigation was to understand the alterations in the trunnion dimensions and surface roughness characteristics as a result of corrosion product build-up.

Influence of Assembly Force and Distraction on the Femoral Head-Taper Junction.

Background: This study investigates if the placement of femoral heads (trials and actual implants) using varying impaction forces causes physical compromise to the trunnion.

Methods: Trunnion and head taper wear patterns were evaluated after impaction and removal of new femoral stem trunnions and ceramic heads at various impaction loads (2 kN, 4 kN, or 6 kN, n = 6/group). In addition, trunnion wear patterns were measured after plastic trials were hand-placed on new trunnions and underwent range of motion testing in a Hip Simulator (n = 5).

Impaction Force Influences Taper-Trunnion Stability in Total Hip Arthroplasty.

Background: This study investigated the influence of femoral head impaction force, number of head strikes, the energy sequence of head strikes, and head offset on the strength of the taper-trunnion junction.

Methods: Thirty titanium-alloy trunnions were mated with 36-mm zero-offset cobalt-chromium femoral heads of corresponding taper angle. A drop tower impacted the head with 2.

Friction in modern total hip arthroplasty bearings: Effect of material, design, and test methodology.

The purpose of this study was to characterize the effect of a group of variables on frictional torque generated by acetabular components as well as to understand the influence of test model. Three separate test models, which had been previously used in the literature, were used to understand the effect of polyethylene material, bearing design, head size, and material combinations. Each test model differed by the way it simulated rotation of the head, the type of frictional torque value it reported (static vs.

Metal-on-metal bearings: the problem is edge-loading wear.

Metal-on-metal bearings are promoted as a low wear bearing alternative to traditional hip replacement bearings. While most in vitro studies support this, recent clinical reviews have found a significant number of early revisions in some designs of metal-on-metal bearings related to wear. Metal-on-metal bearings exhibit a bi-phasic wear pattern with high initial wear that generally settles down to low steady state wear.