Background: In revision total hip arthroplasty, bone loss due to
loosening and migration of the acetabular component makes fixation of a new
implant difficult. The purpose of this study was to evaluate the clinical and
radiographic outcomes of the use of the Ganz reinforcement ring with
nonstructural allograft in the reconstruction of acetabular defects.
Methods: Sixty-one acetabular revisions performed with use of the
Ganz reinforcement ring and nonstructural allograft, between 1989 and 1992, in
fifty-seven patients with aseptic loosening met our selection criteria. Eleven
hips in eleven patients were lost to follow-up, leaving fifty hips available
for evaluation five years or more following surgery. According to the American
Academy of Orthopaedic Surgeons classification, twenty-four acetabular defects
were Type II, twenty-four were Type III, and two were Type IV. Clinical and
radiographic evaluations were carried out at a mean of six and nine years
after surgery. Twelve more patients were lost to follow-up before the most
recent evaluation.
Results: The mean Merle d'Aubigné composite score increased
significantly compared with the preoperative score (p < 0.001). There were
seven failures: six cases of aseptic loosening and one case of septic
arthritis. Graft incorporation and bone remodeling occurred in all hips but
three in which the ring fixation had been inadequate at the time of surgery.
The Kaplan-Meier survivorship rate, with use of revision or loosening of the
component as the criterion of failure, was 81% at ten years. Inadequate
fixation of the implant at the time of surgery was the only multivariate
predictor of failure (p = 0.003).
Conclusions: Patients treated with acetabular revision with a Ganz
reinforcement ring had reconstitution of periacetabular bone stock as well as
good clinical and radiographic results, provided that the ring had been fixed
adequately at the time of surgery. This procedure may not be the preferred
approach for reconstructing segmental defects of the medial wall or pelvic
discontinuity.
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.