BACKGROUND AND PURPOSE In traditional radiostereometric analysis (RSA), 1 segment defines both the acetabular shell and the polyethylene liner. However, inserting beads into the polyethylene liner permits employment of the shell and liner as 2 separate segments, enabling distinct analysis of the precision of 3 measurement methods in determining femoral head penetration and shell migration. PA...

BACKGROUND A common clinical scenario encountered by an orthopaedic surgeon is a patient with a secure cementless acetabular shell and a failed polyethylene liner. One treatment option is to cement a new liner into the fixed shell. The purpose of this study was to evaluate technical variables to improve the mechanical strength of such cemented liner constructs. METHODS The contributions of sh...

We report a complication during total hip arthroplasty using an uncemented press-fit acetabular shell and ceramic liner for a woman with osteoarthritis. Fracture of the ceramic liner occurred during its insertion owing to non-concentric reduction. The main body of the ceramic liner became wedged in the acetabular shell and was resistant to removal. The shell itself was immovable owing to the pr...

We reviewed the initial post-operative radiographs of the Trident acetabulum and identified a problem with seating of the metal-backed ceramic liner. We identified 117 hips in 113 patients who had undergone primary total hip replacement using the Trident shell with a metal-backed alumina liner. Of these, 19 (16.4%) were noted to have incomplete seating of the liner, as judged by plain anteropos...

Cardboard liners are often installed within automotive drive shafts to reduce radiated noise over a certain frequency range. However, the precise mechanisms that yield noise attenuation are not well understood. To overcome this void, a thin shell (under free boundaries) with different cardboard liner thicknesses is examined using analytical, computational and experimental methods. First, an exp...

In this article, we present a 48-year-old female case who had an unsuccessful previous forte ceramic-on-ceramic total hip arthroplasty for early coxarthrosis secondary to acetabular dysplasia. She had fracture and protrusion of the ceramic liner through the titanium acetabular shell without any apparent trauma, possibly resulting from the mistake during the implantation of the ceramic liner int...

The aim of this study was to investigate the association between helmet component characteristics with frequency and distribution of head and brain injury (diffuse and focal) among motorcyclists in Klang Valley, Malaysia. In Malaysia, helmet law was implemented in 1973 (MIROS, 2008). To date, high helmet wearing rate was observed among Malaysian motorcyclists (i.e. 90% among riders) (World Heal...

This study suggests that contemporary modular acetabular shell designs employing ceramic liners deform during implantation where acetabular bed under-reaming is employed. The liner retention strength did not degrade by comparison to non-deformed shells using ASTM static push-out methods. A larger question, however, is the influence of this deformation on liner retention strength over time when ...

INTRODUCTION In cementless hip arthroplasty fixation of acetabular cups is often achieved using a press-fit between the cup and the bone, where the acetabulum is typically under-reamed by 1-4mm [1-4] with respect to the size of the cup. Deformation of the cups during insertion remains a concern as it could lead to changes in the clearance and sphericity of the bearing, which can adversely affec...

PURPOSE To review mid-term results after replacing the polyethylene liner in a well-fixed acetabular shell. METHODS 22 patients underwent replacement of the polyethylene liner in a well-fixed acetabular shell using cementation. The inner surface of the metal shell was scored with grooves (1 to 2 mm deep) for cement interdigitation. Trial liners were used to assess the appropriate size, with a...