Introduction: New biological approaches to reconstruction of major bone deficiency such as the use of bone substitutes and growth factors are being developed. This paper reports on the adverse response to the Bioglass in comparison to allograft alone.

Aim: To compare the biological response to femoral impaction grafting and a cemented femoral stem when using allograft bone versus allograft bone plus a synthetic bone graft substitute, Bioactive glass.

Methods: Eighteen merino wethers underwent a left cemented hemi-arthroplasty and were randomised to have impaction allografting of the femur using either allograft alone (allograft group) or a 50:50 mix of allograft and Bioactive glass (Bioglass group). After sacrifice at 12 weeks, histological analysis of the femora at the levels of the proximal, mid and distal femoral stem and distal to the stem was undertaken.

Results: In the allograft group, there was a consistent response with bone graft incorporation being greatest in the proximal femur and occurring progressively less, more distally. Mineralised bone apposition in the graft occurred post-operatively after eight weeks. In contrast, in the Bioglass group, the response was inconsistent. Bone graft incorporation was either minimal, or there was partial or complete resorption of the bone graft with replacement by particulate-laden fibrous tissue and resorption of endocortical bone. Inflammation of the capsule tissue was noted in some cases.

Conclusion: In comparison to allograft alone, the use of Bioglass to supplement allograft for use in impaction grafting in ovine hip arthroplasty gave inferior results.

There is a lack of properly undertaken comparative studies of total hip replacement (THR). A randomised trial was established to examine the hypothesis that there are no important differences in clinical outcome at 2 years and at long-term follow-up between cemented and uncemented primary THR in middle aged patients.Eighty-three patients with 90 osteoarthritic hips were randomised to a cemented Exeter THR involving a matte or polished tapered stem (n=47, median age 68yrs) or an uncemented PCA proximally porous-coated cobalt-chrome stem and porous coated press fit cup (n=43, median age 66yrs). Patients underwent immediate full weight bearing post-operatively. The follow-up period is 8 to 16 years. The median Harris hip scores for the cemented and uncemented groups respectively were 92 and 95 at 2 years and 89 and 96 at long-term follow-up. Four cemented hips have been revised for aseptic loosening. There have been no failures of the polished stems. An analysis of a larger series of matt versus polished cemented stems also found that the results of the polished stems were superior. Four uncemented hips have been revised, two more recently for acetabular wear and osteolysis. There was a high rate of radiographic demarcation of the cemented cups. There were no important differences in the clinical scores between cemented and uncemented THR. Some matte surfaced femoral stems failed and this trend was confirmed by analysis of a larger series. Osteolysis around the uncemented acetabular components is a concern. Importantly immediate weight bearing was associated with good results of uncemented stems.