Update--"Big-head": the solution to the problem of hip implant dislocation?

New friction couples, initially intended to limit osteolysis risk due to debris, have enabled larger implant head diameters to be developed to resolve the problem of hip implant dislocation. The Symposium demonstrated that, whatever the configuration, increased head diameter significantly reduced the incidence of dislocation, but that none of the friction couples fulfilled the mechanical and/or biomechanical charge-book for consistently reliable use of large diameter heads. The greatest caution is therefore recommended in their implementation.

Metal-on-metal: history, state of the art (2010).

The history of metal-on-metal bearing began with K. Mc Kee. Several "episodes" have marked the history of metal-on-metal articulations, and each has contributed to a better understanding of this type of tribology.

Large diameter head metal-on-metal bearings total hip arthroplasty: preliminary results.

Introduction: Although the use of the metal-on-metal bearings has been validated over the long term in total hip arthroplasty (THA) for standard 28 and 32 mm diameters, and over the medium term in resurfacing procedures, the use of larger metal head size in conventional THA has not yet been extensively reported.

Hypothesis: The large-diameter metal-on-metal head is beneficial in terms of implant stability without altering the result in terms of function and bone fixation compared to the standard 28 and 32 mm diameters.

Objective: The objective was to test this hypothesis by assessing the short-term clinical and radio graphic results of a metal-on-metal large-diameter heads THA system, using cups from the resurfacing hip concept.

A comparison of the penetration rate of two polyethylene acetabular liners of different levels of cross-linking. A prospective randomised trial.

We carried out a prospective randomised study designed to compare the penetration rate of acetabular polyethylene inserts of identical design but different levels of cross-linking at a minimum of four years follow-up. A total of 102 patients (102 hips) were randomised to receive either highly cross-linked Durasul, or contemporary Sulene polyethylene inserts at total hip replacement. A single blinded observer used the Martell system to assess penetration of the femoral head.