Posterior approach and dislocation rate: A 213 total hip replacements case-control study comparing the dual mobility cup with a conventional 28-mm metal head/polyethylene prosthesis - 10/02/11
Summary |
Introduction |
Dislocation is a frequent complication of total hip arthroplasties (THA) especially in older patients, especially when using a posterior approach. In these cases, dual mobility (DM) cups developed by Gilles Bousquet in 1975 can be indicated to reduce this complication risk.
Hypothesis |
Dual mobility cups reduce the rate of dislocation in primary total hip arthroplasty using posterior approach in a single-surgeon series.
Aim |
Test this hypothesis in a controlled study to compare the rate of dislocation in primary total hip arthroplasties done in patients over 50years old either with a dual mobility cup or a conventional metal-on-polyethylene 28-mm diameter head.
Patients and methods |
Two consecutive series of primary total hip replacements were performed by a single surgeon using a posterolateral approach. The piriformis tendon was left intact. The DM series included 105 patients who underwent arthroplasty between January 2005 and June 2007 with a dual mobility cup (60 women and 45 men, mean age 76.6±5.65years old [53–93]). The control series (S series) included 108 patients who underwent arthroplasty (56 women and 52 men, mean age 74.2±5.9years old [53–87]) with a conventional 28-mm polyethylene cup between January 2003 and June 2005. All hip replacements included a 28-mm metal-polyethylene cup and a 12–14-mm Morse taper. Both groups were comparable for gender, diagnosis, body mass index, type of anesthesia and ASA score distribution. All patients included in this series had a minimum follow-up of 1year.
Results |
There were no dislocations in the DM series and five early dislocations (before the third month) in the S series for a rate of 4.63%. Although the rate of dislocation was higher in the S series (4.63% vs 0%), the difference was barely significant (P=0.0597).
Discussion |
This study comparing the incidence of dislocations after THA with conventional or dual mobility cups, shows that even using a posterior approach and in older patients, dual mobility cups increase stability with no postoperative dislocations. Although results are barely significant, a larger series should confirm the benefit of this implant. In this series, morbidity was not increased with dual mobility cups.
Level of evidence |
Level III: retrospective case-control study.
Le texte complet de cet article est disponible en PDF.Keywords : Dislocation, Total hip prosthesis, Dual mobility cup, Posterior approach
Plan
Vol 97 - N° 1
P. 2-7 - février 2011 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.