Compared with physiologic healing in the sham group, callus formation in the osteoporotic (OP) control (C) group was enhanced but unstructured and less dense. Estrogen (E) administration induced less callus formation, but the callus present was very compact and dense, with increased amounts of trabecular structure. The alendronate (ALN) group displayed fewer and unconstrained calluses and trabeculas.Reproduced with permission from Springer New York LLC from Kolios L, Hoerster AK, Sehmisch S, et al. Do estrogen and alendronate improve metaphyseal fracture healing when applied as osteoporosis prophylaxis? Calcif Tissue Int. 2010;86:23–32.