Background: During revision hip replacement surgery, the cementless
acetabular shell is often well fixed but the locking mechanism may be
ineffective. Cementing a new liner into the existing acetabular shell (the
double-socket technique) can provide a simple solution. The purposes of the
present study were to review our initial clinical results and to define the
potential limitations of this technique.
Methods: Thirty-two hips with a preexisting well-fixed acetabular
socket that had been in situ for an average of 8.6 years were treated with the
insertion of a new polyethylene liner (seventeen hips) or a metal liner
(fifteen hips) with use of cement. The indication for this technique was a
deficient locking mechanism in twenty-two hips and the unavailability of a
matching liner in ten hips. Anteroposterior radiographs of all hips were
analyzed by a single independent reviewer.
Results: The mean duration of follow-up was 5.1 years. Six hips
required a reoperation after a mean of 29.7 months; the reasons for the
reoperations included aseptic failure of the acetabular construct (four hips),
instability (one hip), and sepsis (one hip). The University of California at
Los Angeles hip scores improved significantly (p < 0.001) compared with the
preoperative values; specifically, the mean score improved from 6.2 to 9.1 for
pain, from 6.3 to 8.3 for walking, from 6.2 to 7.8 for function, and from 4.7
to 5.8 for activity. The prevalence of dislocation was 22%. Kaplan-Meier
analysis with revision as the end point revealed a five-year survival rate of
78% (95% confidence interval, 55% to 91%).
Conclusions: The double-socket technique is a good alternative to
acetabular socket removal for suitable candidates who have a well-fixed
cementless socket with an inner diameter that is larger than the outer
diameter of the cemented liner. This technique preserves acetabular bone stock
and permits conversion to alternate bearing surfaces. We believe, however,
that removal of a well-fixed acetabular shell or the use of a constrained
liner should be strongly considered for patients with a history of hip
Level of Evidence: Therapeutic study, Level IV (case
series [no, or historical, control group]). See Instructions to Authors for a
complete description of levels of evidence.