ABSTRACT
BACKGROUND: Biomedical implants have been widely used in various orthopedic treatments. However, the existing bone implants often have the disadvantages of poor mechanical properties, immune response, microbial infection, poor healing and so on. Different surface modification techniques can effectively make up for these shortcomings. OBJECTIVE: To summarize the surface modification techniques of the current bone tissue engineering implants. METHODS: The first author searched the PubMed, CNKI, and VIP databases to retrieve the articles regarding repair of tuberculous bone defect published during 2000-2009 with the search terms “bone tissue engineering; bone implant; surface modification; coating” in Chinese and English, respectively. The articles published recently or in high-impact journals were included in this study. RESULTS AND CONCLUSION: The surface of bone tissue engineering implants was modified by inorganic and organic components or by changing the surface topography of the implants. This improves the osteogenesis, bone conductivity, bacteriostasis, and biocompatibility of bone implant to different degrees. However, we need to solve some problems before this new implant is applied to the clinic: how to determine the optimal concentration of different surface modification components, maximize bone healing, inhibit bacterial activity, and avoid other adverse reactions; how to avoid foreign body reaction and immune response caused by particles generated by surface abrasion of these bone tissue engineering implants over time; how to incorporate various growth factors, proteins and other biological molecules into the coating without damaging their respective chemical structures and functions; how to guide the release of growth factors and molecules in a coordinated and controllable way.
ABSTRACT
PURPOSE: To report the results of acetabular revisions performed with the cementless, hemi-spherical porous coated component supported by viable host bone and minimal allobone graft for acetabular deficiencies. MATERIALS AND METHODS: A retrospective study was completed for 22-revision acetabular components, using the cementless hemispherical porous coated prosthesis and minimal femoral head allograft. There was an average follow up of 48 months, with a range of 24 to 84 months. Radiographic measurements were performed in several aspects; cup-allograft contact, inclination, vertical and horizontal migration of acetabular cup, and acetabular zone by modified zone of DeLee and Charnley, in which location, size and progression or non-progression of radiolucent zone were recorded. The acetabular deficiencies were classified by the American Academy of Orthopaedic Surgeons Committee and were type I in 2 hips (9%), type II in 12 hips (55%), and type III in 8 hips (36%). Twenty acetabular cup cases of Harris-Galante II were used in this study, 1 case of Harris- Galante I, and 1 case of Duraloc. The average size of the cup was 57(44-66) mm. RESULTS: The average cup-allograft contact was 72.5% in 19 cases and we could not differentiate the margin between the host bone and the allograft in 3 cases. There was no significant vertical or horizontal migration of acetabular cup. Radiolucent zones in follow-up radiographs were 8 cases in zone IA, 4 cases in zone IB, 4 cases in zone IIB, 9 cases in zone IIC, 8 cases in zone IIIA, and 7 cases in zone IIIB. One case showed 2 mm radiolucent area in zone IIC and another case showed 3 mm radiolucent area in zone IIB, but the radiolucencies were not progressive. The remaining cases showed less than 0.5 mm radiolucent area or no radiolucent zone. The average period of bony incorporation was 13.1 months. CONCLUSIONS: We suppose that acetabular revision with the cementless hemispherical porous coated cup supported by viable host bone and minimal bone graft produces good results.