RT Journal
A1 Jacobs, Joshua J.
A1 Rosenberg, Aaron G.
A1 Galante, Jorge O.
A1 Berger, Richard
A1 Quigley, Laura
A1 Gitelis, Steven
A1 Sheinkop, Mitchell
A1 Della Valle, Alejandro González
A1 Ruzo, Patricio Salonia
A1 Li, Stephen
A1 Pellicci, Paul
A1 Sculco, Thomas P.
A1 Salvati, Eduardo A.
T1 A Question of Prevalence: Liner Dislodgment in Harris-Galante Acetabular Components
JF The Journal of Bone & Joint Surgery
JO The Journal of Bone & Joint Surgery
YR 2002
FD January 1
VO 84
IS 1
SP 143
OP 144
DO 
UL http://dx.doi.org/
AB 
We read with great interest "Dislodgment of Polyethylene
Liners in First and Second-Generation Harris-Galante Acetabular
Components. A Report of Eighteen Cases" (2001;83:553-9),
by Della Valle et al. One of the shortcomings of this otherwise
informative article was that the authors were unable to provide
a denominator; that is, they could not report on the prevalence
of this complication. We used the Harris-Galante first and second-generation acetabular
components extensively in the 1980s and early 1990s1-4. In a recent review of our joint
replacement registry, we identified 560 Harris-Galante-I cups implanted
in primary or revision total hip arthroplasty with a minimum follow-up
of seven years and found that four (0.7%) of them had dissociation
of the acetabular liner. We also identified 476 Harris-Galante-II cups
implanted in primary or revision total hip arthroplasty with the
same minimum follow-up and found that six (1.3%) had dissociation
of the liner. The wear rate of the liner in patients with this complication
is of considerable interest to us. For the ten patients who had
dissociation of the liner, the mean wear rate was 0.23 mm/yr
compared with a mean wear rate of 0.13 mm/yr for the patients
without this complication. Thus, liners that had dissociation had
almost twice the rate of polyethylene wear as those that did not. When
the head of the femoral component is eccentrically located within
the acetabular liner, the shell-liner interface is exposed to large
torsional moments, increasing the propensity for dissociation through
overload of the capture mechanism used in both the first and second-generation
components. These torsional moments would be exacerbated by an elevated
liner or a skirted femoral head, which are more prone to impingement,
if the head is eccentrically situated in the liner. Once dislodgment
has occurred, a revision of the acetabular component is necessary because
of the damage caused to the metal shell by fretting of the shell against
the femoral head. In the presence of a well-fixed bone-ingrown acetabular
component, this revision can be a difficult procedure fraught with potential
major complications. In addition, severe metallosis is always a
risk. We believe that the risk of dislodgment can be reduced by
early intervention when there is evidence of accelerated polyethylene
wear. Performing a liner exchange early and restoring the superimposition
of the center of the acetabular component on the center of the femoral
head can dramatically reduce eccentric torsional loads. Liner exchange
is relatively simple, and major complications can be avoided. If the
capture mechanism is damaged, the new polyethylene liner can be cemented
into the existing shell.