title: Differential effect of a bone morphogenetic protein-7 (OP-1) on primary and revision loaded, stable implants with allograft.
abstract: Morselized impacted bone allograft is often used to reconstruct the bone bed in the revision of failed total joint arthroplasties. We hypothesized that addition of the bone morphogenetic protein OP-1 (BMP-7) to bone allograft would improve early implant fixation. We inserted one loaded 6-mm-diameter titanium implant (surrounded by 0.75-mm gap) in each medial condyle of 24 canines. On one side, the implant was inserted in a controlled experimental revision setting resembling the clinical revision situation. A primary implant was inserted on the contralateral side in a previously unoperated site. Three groups were studied: 1) allograft alone, 2) allograft + 0.4 mg OP-1, and 3) allograft + 0.8 mg OP-1. Implant fixation was evaluated at 4 weeks. Grafted implants inserted in the primary setting without OP-1 had better fixation than the grafted revision setting with or without OP-1 (significantly more bone coverage, more mineralized tissue in the gap, and better mechanical interface strength). However, grafted primary implants with OP-1 had impaired fixation compared with grafted primary implants without OP-1 (less bone coverage of the implant and less bone formation in the gap). In contrast, grafted revision implants with OP-1 significantly increased implant fixation compared with grafted revision implants without OP-1 (increased mechanical interface strength and fraction of mineralized tissue in the gap). We found no differences between the two doses in any of the settings. Addition of OP-1 to bone allografted implants may show benefit at sites with impaired bone healing capacities, such as the revision setting.
authors.affiliation: Department of Orthopaedic Surgery, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Kjeld
authors.initials: K
authors.lastname: Søballe
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Jensen
authors.forename: Olivier
authors.initials: O
authors.lastname: Mouzin
authors.forename: Louis
authors.initials: L
authors.lastname: Kidder
authors.forename: Joan E
authors.initials: JE
authors.lastname: Bechtold
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001846:Bone Development / Q000187:drug effects; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D016025:Bone Transplantation; D001842:Bone and Bones / Q000033:anatomy & histology; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D019736:Prostheses and Implants; D011475:Prosthesis Failure; D012086:Reoperation; D013499:Surface Properties; D014025:Titanium; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D016212:Transforming Growth Factor beta; D014025:Titanium