Hydroxyapatite in revision of total hip replacements with massive acetabular defects: 4- to 10-year clinical results

Hydroxyapatite coated with insulin-like growth factor 1 (IGF1) stimulates human osteoblast activity in vitro

We studied the effects of a hydroxyapatite-tricalcium phosphate material coated with Insulin-like Growth Factor 1 (IGF1) on cell growth, collagen synthesis and alkaline phosphatase activity (ALP) of human osteoblasts in vitro. Cell proliferation was stimulated when osteoblasts were incubated with untreated hydroxyapatite (HA) and it was further increased by exposure to IGF1-coated HA. 3H-Proline uptake was significantly increased by treatment with either HA or IGF1-coated HA but no significant differences were found between these two groups. ALP activity was enhanced by exposure to HA, with respect to the control, and further increased by treatment with IGF1-coated HA. Our findings suggest that HA is useful for promoting osteoblast activity and IGF1 may help to improve its biological characteristics.

A-W glass ceramic as a bone substitute in cemented hip arthroplasty: 15 hips followed 2-10 years

We retrospectively reviewed hip arthroplasties in 13 patients (15 hips), in whom we had used apatite-wollastonite (A-W) glass ceramic together with auto- or allograft for augmentation of severe bone deficiency. 11 cemented sockets and 4 stem revisions were included and followed for 2-9.6 years. There were no radiolucent lines between A-W glass ceramic and surrounding bone, and remodeling of the bone graft containing A-W glass ceramic was observed. No migration of cemented sockets was seen except in 1 case, which was revised. In this case, direct bonding between bone and A-W glass ceramic granules was present histologically. In 4 stem revisions, 5 mm subsidence occurred in 1 case. However, the stem became stable and remodeling of the grafted bone occurred. An artificial bone material, such as A-W glass ceramic, can be used under high-load conditions, because of its good mechanical properties.