We previously reported the results at a mean of five years following the
use of a tripolar constrained acetabular component to treat recurrently
dislocating total hip prostheses. In this study, we report the results after
longer follow-up, with emphasis on the prevalence of implant loosening,
osteolysis, and later recurrent instability. Fifty-five patients treated with
a total of fifty-six constrained acetabular components because of recurrent
dislocations of a total hip prosthesis (average, six dislocations; range, two
to twenty dislocations) were followed for an average of 10.2 years (range, 7.0
to 13.2 years) or until death. Four (7%) of the fifty-six hips had a
subsequent dislocation or failure of the device. Three femoral components (5%)
and two acetabular components (4%) were revised because of aseptic loosening.
One hip was revised because of osteolysis. We concluded that this constrained
acetabular component provides durable protection against additional
dislocations without substantial deleterious effects on component fixation. We
use this device to treat recurrent dislocation when other modalities are
unlikely to be effective.
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.