Hierarchical　micropore/nanorod-patterned　strontium　doped　hydroxyapatite　(Ca9Sr1(P0(4))(6)(0H)(2,)　Sr-1-HA)　structures　(MNRs)　with　different　nanorod　diameters　of　about　30,　70　and　150　nm　were　coated　on　titanium,　to　investigate　the　effect　of　nanorod　diameter　on　osteogenesis　and　the　involved　mechanism.　Compared　to　micropore/nanogranule-patterned　Sr-1-HA　coating　(MNG),　MNRs　gave　rise　to　dramatically　enhanced　in　vitro　mesenchymal　stem　cell　functions　including　osteogenic　differentiation　in　the　absence　of　osteogenic　supplements　and　in　vivo　osseointegration　related　to　the　nanorod　diameter　with　about　70　nm　displaying　the　best　effects.　MNRs　activated　the　cellular　Wnt/beta-catenin　pathway　by　increasing　the　expression　of　Wnt3a　and　LRP6　and　decreasing　the　expression　of　Wnt/beta-catenin　pathway　antagonists　(sFRPl,　sFRP2,　Dkkl　and　Dkk2).　The　exogenous　Wnt3a　significantly　enhanced　the　beta-catenin　signaling　activation　and　cell　differentiation　on　MNG,　and　the　exogenous　Dkkl　attenuated　the　enhancing　effect　of　MNRs　on　them.　The　data　demonstrate　that　MNRs　favor　osseointegration　via　a　Wnt/beta-catenin　pathway.　(C)　2018　Elsevier　Inc.　All　rights　reserved.