BACKGROUND: Acetabular fixation during revision total hip
arthroplasty in patients who have a nonsupportive superior dome and proximal
migration of the acetabular component (a Paprosky Type-IIIa defect) cannot be
achieved reliably with use of a hemispherical porouscoated component alone.
The purposes of the present study were to determine the long-term results
associated with the use of a porous-coated hemispherical acetabular component,
supported with a distal femoral structural allograft, for revision at the site
of a Type-IIIa defect and to determine if graft resorption leads to late
METHODS: Thirty-one patients who had an acetabular reconstruction
with use of a distal femoral allograft for the treatment of a Type-IIIa defect
between January 1985 and December 1990 were followed annually with clinical
and radiographic evaluations. At the time of the latest follow-up, eight
patients had died and one patient had been lost to follow-up. One of the
patients who died had had a clinical failure at 4.5 years postoperatively and
was included in the analysis. Therefore, twenty-three patients, who had had an
average age of sixty-one years at the time of the index procedure, were
evaluated at an average of 10.3 years postoperatively.
RESULTS: Five acetabular components were re-revised because of
aseptic loosening at an average of 5.3 years after the index procedure.
Radiographically, all but one of the remaining components were stable and
showed evidence of bone ingrowth. The average Merle D'Aubigné and
Postel hip score improved from 5 points preoperatively to 10 points at the
time of the latest follow-up. Allograft bone resorption, although difficult to
quantitate, was observed around six of the seventeen stable components and
around two of the five components that failed clinically.
CONCLUSIONS: Acetabular revision with use of a porous-coated
acetabular component along with a structural distal femoral allograft for the
treatment of a Type-IIIa defect demonstrated a high rate of clinical and
radiographic success after an average of ten years of follow-up.