Living cells in 1 of 2 frozen femoral heads.

Allogeneic, frozen bone is now the most commonly grafted tissue (Norman-Taylor and Villar 1997). Tissue banks collect bone material according to protocols developed with the aim of maintaining osseoinductive properties of grafts as well as preventing transmission of viral or bacterial diseases (Standards from the American Association of Tissue Banks (AATB) or from the European Association for Musculo-skeletal Transplanting (EAMST)). Standard procedures include cryopreservation of tissue at -80 degrees C, which is generally considered to devitalize the bone by killing all cells present, resulting in reduced immunogenicity of the graft. The osseoinductive properties of frozen, allogeneic bone grafts have therefore mainly been attributed to the dead bone matrix, that may provide osteoblast-stimulating growth factors and other essential proteins, and/or an osteoclast substrate to direct bone remodeling (Aspenberg et al. 1996, Kingsmill et al. 1999). Recently however, it was suggested that some cells in bone biopsies may survive standard bone bank freezing procotols. It is unclear whether vital cells are present in other bone banks and whether these cells can contribute to the clinical outcome of frozen allogeneic bone grafting. In this report, we show that frozen bone biopsies, obtained from the Erasmus Medical Center bone bank may contain living cells that can be cultured in vitro. These cultured cells were found to originate from the donor by genotyping.