[Commercially available substitutes for transplants of human bone]

As alternative or supplements to transplantation of human bone in cases of bone defects or reconstructions of bones, a series of commercially available materials exist. Kieler bones, which are made from bovine bones are the oldest preparation. Kieler bones consist of up to 30% protein. This gives the bone elasticity but may also involve immunogenic reactions to the implant. Calcium phosphate, in the form of synthetic or semi-synthetic hydroxyapatite or hydroxyapatite/tricalcium phosphate, is, on the other hand, quite inelastic which makes these implants unsuitable in regions with mechanical stress. Proplast consists of carbon fibres coated with Teflon and may be employed for subperiostal reconstructions. BOP is a new system of synthetic materials built up from polyamide fibres and/or absorbable matrix. This system combines mechanical strength with ingrowth of bone but, as yet, experience with this material is only limited. Commercial substitutes for human bones should only be employed on limited indications and taking the mechanical properties of the implants and the capacity for substitution with regenerating bony tissue into consideration.