Background: Exchange of modular components is
a treatment option for the correction of recurrent dislocation of
a total hip replacement. In this study, we reviewed our experience
with this technique in order to define patient selection criteria
and to report the outcome of treatment.
Methods: Of 2935 hips treated with primary porous-coated
total hip arthroplasty, fourteen (in fourteen patients) that met
certain preoperative and intraoperative criteria were treated with modular
component exchange because of recurrent hip instability. The primary
arthroplasties in these fourteen patients had been performed through
a posterior approach. At the revisions, we removed any sources of
osseous or soft-tissue impingement that contributed to dislocation.
Acceptable stability at the completion of component exchange was
defined as stability in maximum flexion, in full extension with
external rotation, and in at least 45° of internal rotation with
the hip in 90° of flexion and maximum adduction.
Results: One patient was lost to follow-up. At a
mean of 5.8 years (range, 2.8 to 11.8 years) after the revision,
ten of the remaining thirteen patients had not had a dislocation.
Of the three patients in whom the hip dislocated after the modular
component exchange, only one had recurrent dislocation; thus, recurrent
dislocation was eliminated in twelve of thirteen patients.
Conclusions: In selected cases, modular component
exchange for the treatment of recurrent hip dislocation has a success
rate comparable with that of more extensive operations. This method should
be considered because it avoids the morbidity associated with revision
of well-fixed components. However, to ensure the appropriateness
of this surgical option, each patient must be thoroughly evaluated
to identify all factors that contribute to instability and adequate
intraoperative stability must be achieved.