Influence of surfactant molecules as air-entraining agent for bone cement macroporosity

Calcium phosphate bone cements (CPBCs) represent a potential synthetic alternative to bone-graft materials in bone surgery applications. CPBCs are biocompatible, bioresorbable, and slowly are replaced by new bone in vivo. However, CPBCs do not develop a macroporosity during setting that would allow fast bone ingrowth and good osteointegration of the implant. For this reason, recent research has approached the problem of inducing macroporosity inside the bone cement without influencing its normal setting. In this study, a new method for obtaining injectable macroporous CPBCs is proposed. It is based on the use of sodium dodecyl sulphate (SDS) as an air-entraining agent. The results have shown that the liquid-to-powder ratio and the SDS concentration, as well as the diameter and the interconnectivity of the macropores, can control the micro- and macroporosity. This new technology can be used to develop and optimize new commercial products for osteoporotic bone filling applications. Furthermore, the presented method also can be used at low temperatures before an operation to produce preformed implants to fit the particular needs of a patient.