REVISION OF THE ACETABULAR COMPONENT OF TOTAL HIP ARTHROPLASTY WITH A FROZEN MASSIVE STRUCTURAL PELVIC ALLOGRAFT: A PROSPECTIVE STUDY WITH FIVE YEARS FOLLOW UP

Abstract

We evaluated the use of a hemipelvic acetabular transplant in twenty revision hip arthroplasties with massive acetabular bone defects (Paprosky IIIB) at a mean follow-up of 5-years (4–10 years). These defects were initially trimmed to as geometric a shape as possible by the surgeon. The hemipelvic allografts were then cut to a geometric shape to match the acetabular defects and to allow tight stable positioning of the graft between the host ilium ischium and pubis. The graft was further stabilised with screw fixation. A cemented cup (without a reinforcement ring) was entirely supported by the allograft in all procedures.

We report 65% good intermediate-term results.

There were seven failures (five aseptic loosening and two deep infections). Radiographic bone bridging between the graft and host was evident in only one of these cases. Aseptic graft osteolysis began radiographically at a mean of 14 months and revision occurred at a mean of 2 years in the 5 aseptic failure cases. All 5 cases could be reconstructed again due to the restoration of bone stock provided by the hemipelvic graft. One infected case was able to be reconstructed using impaction allografting and the other was converted to a Girdlestone hip.

Thirteen of twenty acetabular reconstructions did not require revision. Radiographic bone bridging between the graft and host was evident in 12 cases. In 2 cases, ace-tabular migration began early (at 5 and 27 months) but stopped (at 35 and 55 months). These 2 cases have been followed for 6 and 9 years respectively, with no further migration. Two dislocations occurred but did not require acetabular revision.

The function of these hips is good with a mean Postel Merle D’Aubigne score of 16.5.

We feel that these are satisfactory intermediate term results for massive acetabular defects too large for reconstruction with other standard techniques.