Aim: To assess intra and inter observer variability in classiþcation of cement bone demarcation around a cemented acetabular component. Method: We collected 46 random triplets of radiographs taken six weeks, one year and a mean of 9.5 years post-operatively. Each of the three observers (1,2,3) evaluated all radiographs independently, and the evaluations were repeated by two observers (a, b) after 2 to 4 weeks. Inter and intra-observer variation was evaluated using the kappa coefthorn;cient of agreement. The strength of agreement was interpreted according to the Landis and Koch method. Results: There was substantial agreement in classiþcation of zone 1 for all time points and of all three zones for the þnal radiographs. Classiþcation of zones 2 and 3 were not reliable until after one year of follow-up. Conclusion: We have shown that zone 1 can be assessed reliably by different observers from the þrst follow-up radiograph. Therefore we recommend that zone 1 demarcation should be used as an index of performance comparable between cemented sockets especially where follow up has been less than ten years.

The BOA recommends clinical and radiological follow-up at þve-yearly intervals in order to detect failing implants. We support this recommendation and have shown that with longer followÐup the assessment of demarcation in all three zones has substantial agreement

We have reviewed the intermediate term results of 56 out of 61 consecutive Wagner revision stems implanted without bone graft. After a mean of 5 years (range 4 to 7 years) 49 out of 56 hips were graded as excellent or good based on the Harris Hip Score. The clinical result was not related to the degree of femoral bone defect prior to revision.

49 Out of 56 hips were seen to subside, but this did not affect the hip score at final review. The mean subsidence was 4.8mm (range 0 – 19mm).Only one stem showed continued subsidence after 12 months post-operatively, and this stem achieved a stable position by 24 months. All osteotomies of the femur united with reconstitution of the femoral bone stock. There was a low incidence of complications; one stem showed catastrophic subsidence within 48 hours of surgery, requiring re-revision to a larger Wagner stem. There was one sciatic nerve palsy. 3 hips dislocated on one occasion in the early post-operative period, but were stable at latest follow-up.

In conclusion, the Wagner stem can bypass major proximal femoral bony defects and achieve initial axial and rotational stability in intact diaphyseal bone. Subsequent stem subsidence does not affect clinical outcome, and proximal femoral bony reconstitution is achieved without the need for bone grafting.