title: Bisphosphonate delivery to tubular bone allografts.
abstract: Large structural allografts used for reconstruction of bone defects after revision arthroplasty and tumor resection fracture up to 27% of the time from osteolytic resorption around the fixation screw holes and tendon or ligament attachment sites. Treating structural allografts before implantation with bisphosphonates may inhibit local osteoclastic processes and prevent bone resorption and the development of stress risers, thereby reducing the long-term fracture rate. Taking advantage of allografts' open-pore structure, we asked whether passive soaking or positive-pressure pumping was a more efficient technique for delivering bisphosphonates. We treated matched pairs of ovine tibial allografts with fluids containing Tc-99m pamidronate and toluidine blue stain to facilitate indicator distribution analysis via microSPECT-microCT imaging and light microscopy, respectively. Surfactants octylphenoxy polyethoxy ethanol or beractant were added to the treatment fluids to reduce flow resistance of solutions pumped through the allografts. Indicator distribution after 1 hour of soaking produced a thin ring around periosteal and endosteal surfaces, while pumping for 10 minutes produced a more even distribution throughout the allograft. Flow resistance was reduced with octylphenoxy polyethoxy ethanol but unaffected with beractant. Pumped allografts displayed a more homogeneous indicator distribution in less time than soaking while surfactants enhanced fluid movement.
authors.affiliation: Department of Surgery/Orthopaedic Surgical Service, Memorial Sloan-Kettering Cancer Center, Weill Medical College of Cornell University, 1275 York Ave., Suite A342, New York, NY 10065-6004, USA. direstag@mskcc.org
authors.forename: Gene R
authors.initials: GR
authors.lastname: DiResta
authors.forename: Mark W
authors.initials: MW
authors.lastname: Manoso
authors.forename: Anwar
authors.initials: A
authors.lastname: Naqvi
authors.forename: Pat
authors.initials: P
authors.lastname: Zanzonico
authors.forename: Peter
authors.initials: P
authors.lastname: Smith-Jones
authors.forename: Wakenda
authors.initials: W
authors.lastname: Tyler
authors.forename: Carol
authors.initials: C
authors.lastname: Morris
authors.forename: John H
authors.initials: JH
authors.lastname: Healey
mesh_terms: D000818:Animals; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001859:Bone Neoplasms / Q000601:surgery; D016025:Bone Transplantation; D004164:Diphosphonates / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004285:Dogs; D005260:Female; D012756:Sheep; D014184:Transplantation, Homologous
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates