The bone‐to‐cement interface improvement by ca‐phosphate ceramics

  Background : Polymethylmethacrylate used in surgery is one of the first biomaterials. Conventional histology dissolves the resin; one of the reasons that only few complete histology is published. Objectives and Purpose : The question is, whether a complete histology changes the understanding, influences the application and opens approaches for improvements. The dos and don'ts of the processing technology are presented in reproducible manner. Material and Methods : Ten femurs of giant rabbits were taken from running experiments of femur‐canal filling with bone cement. Different stages were considered for high‐resolution histology and electron microscopy: 4‐weeks‐stage (bone healing), 12‐weeks‐stage (remodelling) and one and two years. A human‐cadaver specimen with a follow up of two years was processed. All animals were perfusion‐fixated and the complete vasculature micro‐casted. Serial cuts were performed with a stone saw, followed by a wet grinding processing. The fluorescence documentation in the High Intensity Incident Fluorescent Light (HIIFL) and Orthoplan Leitz Ploemopak ® was applied and high resolution microradiography used the Siemens Kristalloflex ® . The Scanning Electron Microscopy (SEM) was performed applying deep‐freezing technology for the PSEM‐500. The human specimen was embedded after sectioning using epoxy‐resin. Results : All cement implants showed osseointegration and remodelling with a tangential adherence of bone onto the ceramic/PMMA surfaces. Intact cancellous structures after one and two years did not show any signs of heat necrosis. The human specimen confirmed the results from the animal experiments. Conclusion : The complete bone‐to‐cement histology changed the understanding of the bone cements function, influenced its application and opened new ways for improvement. Microsc. Res. Tech. 76:697–703, 2013 . © 2013 Wiley Periodicals, Inc.