We reviewed the radiographs of thirty-one patients (thirty-two hips) who
had had revision of the acetabular component of a total hip arthroplasty
with a bipolar socket supplemented by allograft and were followed for
twenty-four to forty-eight months. The grafts were categorized according to
their consistency (solid or crushed bone), the location of the acetabular
defect (peripheral [rim] or central), and the extent of the acetabular
defect (contained--the medial part of the acetabular wall was intact, or
non-contained--it was deficient). We recorded the time to incorporation of
the graft, the amount of migration of the socket in the superior and medial
axes, and the percentage of graft remaining at the time of the most recent
follow-up. The time to healing was similar for all categories of grafts.
The central, contained, solid grafts had less resorption than did the
central, contained, crushed-bone grafts, as evidenced by less migration of
the socket during follow-up. The non-contained grafts, in both peripheral
and central locations, were associated with high rates of migration and of
instability of the socket.