Deficiencies of acetabular bone stock at revision hip replacement were reconstructed with two different types of allograft using impaction bone grafting and a Burch-Schneider reinforcement ring. We compared a standard frozen non-irradiated bone bank allograft (group A) with a freeze-dried irradiated bone allograft, vitalised with autologous marrow (group B). We studied 78 patients (79 hips), of whom 87% (69 hips) had type III acetabular defects according to the American Academy of Orthopaedic Surgeons classification at a mean of 31.4 months (14 to 51) after surgery. At the latest follow-up, the mean Harris hip score was 69.9 points (13.5 to 97.1) in group A and 71.0 points (11.5 to 96.5) in group B. Each hip showed evidence of trabeculation and incorporation of the allograft with no acetabular loosening.

These results suggest that the use of an acetabular reinforcement ring and a living composite of sterile allograft and autologous marrow appears to be a method of reconstructing acetabular deficiencies which gives comparable results to current forms of treatment.

The major challenges in an increasing number of periprosthetic femoral fractures are pre-existent aseptic loosening and femoral bone loss. The successful concept of interlocked intra medullarynailing of multi fragmentary femoral fractures has been applicated onperiprosthetic fractures. A specially designed revision stem combines the features of an intramedullary nail in its distal part and of an uncemented coated prosthesis in the proximal part. This prosthesis has been used successfully in elective revision surgery for aseptic loosening.

Thirty-nine patients with periprosthetic fractures have been operated between 1994 and 2000. Eleven patients were male, the mean age was 70,3 years. The series includes three intra operative fractures of the femoral shaft, in which a revision stem was applied, in the other cases the primary intervention was 10.9 years before the periprosthetic fracture. In 16 cases the shaft was loose prior to the fractures, and in 13 cases the cup was loose as well.> A modified transfemoral approach was done in any case, and long revision stem with distal interlocking was applied. The fragments were adapted to the shaft by cerclage wires, and bone grafting was done in 14 selected cases.

All patients could be followed up. In all but 4 cases the fracture was healed and the revision stem was well osteointegrated. Radiologically, the bone stock of the proximal femur was restored by means of bone grafting and fracture healing in this cases. A recurrent revisionhad to be undertaken in four cases due to lack of osteointegration and subsidence of the stem. In 5 cases the cerclage wires had to be removed due to local irritation. 3 patients had a recurrent trauma and a new periprosthetic fracture distal to the tip of the revision stem; plating had to be performed in this cases.

We conclude that interlocked intramedullary stabilisation of periprosthetic fractures with a revision stem can be a option especially in those challenging cases with pre-existent shaft loosening and bone loss.