72.
The dislocating hip replacement – revision with a dual mobility cup
Thomas Jakobsen, Andreas Kappel, Flemming Hansen, Jørgen Søndergaard,
Niels Krarup
Ortopædkirurgisk afdeling Regionshospitalet Viborg; Ortopædkirurgisk
afdeling, Aalborg Universitets Hospital; Ortopædkirurgisk afdeling,
Regionshospitalet Viborg; Ortopædkirurgisk afdeling, Regionshospitalet
Viborg; Ortopædkirurgisk afdeling, Regionshospitalet Viborg
Background:
Recurrent dislocations of hip replacements is a difficult
challange. In 2010, 20% of all revisions where performed because of
dislocation. One treatment option for recurrent dislocations are the use of a
dual mobility cups. However, only few studies have investigated the effect of
dual mobility cups on recurrent dislocations.
Purpose / Aim of Study:
The aim of this study was to retrospective
investigate the effect of dual mobility cups as a treatment for recurrent
dislocations in a consecutive series.
Materials and Methods:
56
consecutive patients were revised in the period
November 2000 to December 2010. The mean age at revision was 72 years
(
SD 11, range 37-92)) and median number of dislocations before revision
surgery were 4 (IQR, 2-11). In all cases, revision was made with a Saturne
dual mobility cup (Amplitude, Neyron, France). The uncemented Saturn cup
consists of two parts. An outer shell with a large inside- diameter. The outer
shell is made of stainless stell and on the outside coated with titanium and
hydroxy-apatite and highly polished on the inside. The outer shell articulates
with an inner shell made of polyethylene. The inner shell articulates with a 28
mm femoral head that is locked into the inner shell. The mean followup period
was 44 mounths (SD 30, range 0.1-119).
Findings / Results:
Three patients (3.7%; SE 2.5) experienced a redislocation.
Four patients (7.1%; SE 3.4) had to be revised. One due to disintegration
between the femoral head and inner shell, one due continued dislocations, and
two due to infection. Leaving an overall survival rate of 92.9% after a mean of
44
months.
Conclusions:
This study advocates the use of a dual mobility cup for treatment
of recurrent dislocations of THR. However, studies with a longer follow up are
needed in order to evaluate implant survival.
