Introduction

The causes for revision of primary total hip arthroplasty (THA) are various and quite well known. The developing use of dual-mobility THA (DM-THA) seems a relevant option to decrease the risk of instability. Due to lack of long-term follow-up, this innovative retentive concept is suspected to increase the risk of polyethylene (PE) wear. The aim of the study was to analyse the causes for DM-THA revision and assess whether or not its occurrence is different from that of fixed-standard (FS) THA, particularly for aseptic loosening or wear and/or osteolysis.

Introduction

Upper femoral fractures include intra and extra-capsular fracture (ECF). For intra-capsular fracture (ICF), hemi-arthroplasty (HA) is the most commonly used treatment. Interest in total hip arthroplasty (THA) is growing because THA yields less revision (4% versus 7%) associated to better functional results despite higher dislocation rate (9% versus 3%). Regarding ECF, internal fixation is the reference treatment. THA could represent a relevant alternative. This study evaluates the efficiency of THA using dual mobility cup (THA-DMC) as treatment of these fractures specially in elderly patients.

BACKGROUND PURPOSES

dislocation is a classical complication in total hip arthroplasty (THA) revision. Cup fixation is the second concern. Since 1998 we routinely use cementless Dual mobility cup (DMC) in revision surgery. In order to know outcomes at 2 years, we followed a prospective series of 78 patients treated in our institution. Purpose is to demonstrate that DMC used in revision THA is safe as regards dislocation risk and bone fixation.

Mid and long-term follow-up of Charnley total hip arthroplasty (THA) demonstrated good functional results with 85% survivorship at 25-year follow-up. However dislocation still remains an unsolved problem. Dislocation may occur all along the patient and implant life. The aim of this study is to answer the question: does Dual Mobility Cup (DMC) decrease the dislocation risk? Method: We report comparative results at ten years of follow-up of 2 groups of primary cemented Charnley-type THA, one with a standard polyethylene cup (group 1, n=215) and the other one with a DMC (group 2, n=105). Results: In group 1, twenty-six dislocations (12.9%) occurred. In group 2 only one dislocation (0.9%) occurred. This dislocation was successfully reduced by close reduction, without any recurrence. This difference was statistically significant (p=0.0018). In group 1, reason for revision was recurrent dislocation in twenty one cases. Five patients have been revised for other reasons. The global revision rate was 12.9%. In group 2, two patients needed revision surgery for aseptic loosening. The global revision rate was 2.1%. This difference was statistically significant (p=0.0054). The goal was reached for the patients of group 2 who had more risks factors of dislocation (age, aetiology, ASA and Devane scores) than those of group 1. When using a DMC, we observed a low rate of dislocation in primary THA (0.9%). This surgical choice seems to be a secure and effective technique in Charnley-type THA, especially in a high risk population.

Introduction

Polyethylene (PE) wear is clearly linked to total hip arthroplasty (THA) failure, leading to osteolysis and decreasing survivorship rates. Dual mobility cups (DMC) are widely used to prevent or treat THA instability. However some studies have pointed PE wear risk as a “dual wear” risk. Hip wear simulation is usually used to understand factors influencing wear and to differentiate design, PE types and materials performances. To date, few works have been published studying dual mobility insert wear.