BACKGROUND:
Studies of acetabular reconstruction with use of cement and bulk bone graft
have demonstrated increasing rates of cup failure in patients with dysplastic
hips seven years after total hip arthroplasty. Comparable data on the
long-term results of bulk bone-grafting done in conjunction with cementless
implants are limited. The aim of this study was to review the clinical and
radiographic results of autologous bulk bone-grafting in conjunction with a
cementless cup.
METHODS:
From 1987 to 1992, forty-seven patients (forty women and seven men, with an
average age of 50.4 years) who had developmental dysplasia of the hip
underwent fifty-six total hip arthroplasties and received a structural graft
in combination with a cementless Harris-Galante type-I cup. All patients were
followed prospectively. In fifty-five hips, implant migration was measured
with single-image radiographic analysis.
RESULTS:
After an average duration (and standard deviation) of 10.2 ± 2.9
years, three patients (four hips) had died. In the surviving patients, four
implants had been revised and two had radiographic evidence of loosening. With
use of revision and loosening as end points, the eleven-year survival rates
were 91.6% and 88.9%, respectively. Of the fifty implants that had no
loosening, fourteen had measurable cup migration, thirty-five had no
migration, and one implant could not be measured. All migrations but one were
progressive. With loosening used as the end point, the survival rate at eleven
years was 100% for the implants with no migration; however, the survival rate
for the cups that had migrated was 69.3% (p = 0.0012).
CONCLUSIONS:
The eleven-year survival rate for the spherical press-fit cups in
combination with bulk bone-grafting is satisfactory, given the complexity of
these reconstructions. However, the difference between the survival of the
implants that had migrated and those that had not was significant. We expect
that the thirteen implants with progressive acetabular migration at the time
of the latest follow-up are at risk for loosening, which will increase the
revision rate for this series in the coming years.