title: Implant placement increases bone remodeling transiently in a rat model.
abstract: To examine bone remodeling following implant placement, 88 female Sprague-Dawley rats underwent either sham ovariectomy (sham-ovx) or ovariectomy (ovx) at 4.5 months. At 11 months, 17 baseline control animals were euthanized, while 71 rats received bilateral intramedullary femoral implants. Implanted rats were randomized to 4-, 8-, or 12-week follow-up times. Microcomputed tomography was used to assess cortical area and trabecular architecture in all rats. Dynamic and static histomorphometry were performed in a subset to examine the trabecular and endocortical bone in the distal femoral metaphysis adjacent to the implant and the periosteal surface at the midshaft superior to the implant (n = 59). Implantation did not affect bone volume in either sham-ovx or ovx rats compared to baseline controls. Implant placement significantly increased mineralizing surface, mineral apposition rate, and bone formation rate in both sham-ovx and ovx rats at the trabecular and endocortical surfaces at four and sometimes 8 weeks, with a return to baseline values by 12 weeks. At the periosteal surface, implant placement increased bone formation at 4 weeks with a return to baseline levels by 8 weeks. Thus, implant placement increases bone remodeling transiently without affecting bone volume in sham-ovx and ovx rats.
authors.affiliation: Department of Anatomy & Cell Biology, Rush University Medical Center, 600 South Paulina, Suite 507, Chicago, IL 60612, USA.
authors.forename: John
authors.initials: J
authors.lastname: Irish
authors.forename: Amarjit S
authors.initials: AS
authors.lastname: Virdi
authors.forename: Kotaro
authors.initials: K
authors.lastname: Sena
authors.forename: Margaret A
authors.initials: MA
authors.lastname: McNulty
authors.forename: Dale R
authors.initials: DR
authors.lastname: Sumner
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000502:physiology*; D004195:Disease Models, Animal; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D008422:Materials Testing; D016348:Osseointegration / Q000502:physiology*; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D010052:Ovariectomy; D010521:Periosteum / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D019736:Prostheses and Implants; D011859:Radiography; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley