title: Load-bearing increases new bone formation in impacted and morselized allografts.
abstract: The effects of mechanical loading on the incorporation of morselized impacted grafts were addressed in this study. Twelve skeletally mature rabbits were surgically treated. Six rabbits received a proximal tibial joint replacement with a tibial tray and a load-bearing 25-mm long stem. The tibia was packed with fresh frozen, morselized, cancellous rabbit bone. No cement was used. In six other rabbits only the stem was inserted, without a tibial tray, leaving the stem and the likewise impacted bone graft mechanically unloaded. The rabbits were euthanized after 6 weeks, and the tibias were sectioned and analyzed by histomorphometric examination. In the loaded specimens the graft was resorbed and replaced by new bone (30% of area of interest) to a larger extent than in the unloaded specimens. Mechanical loading of an impacted, morselized graft surrounding a conical uncemented stem, increased the amount of new bone that replaced the graft. The ability of morselized impacted grafts to allow mechanical stimulation of ingrown tissue appears to be a principal cause for the success of this grafting procedure.
authors.affiliation: Department of Orthopedics, Lund University Hospital, Sweden.
authors.forename: J S
authors.initials: JS
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Tägil
authors.forename: P
authors.initials: P
authors.lastname: Aspenberg
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000502:physiology*; D005069:Evaluation Studies as Topic; D019736:Prostheses and Implants; D011817:Rabbits; D014184:Transplantation, Homologous; D016474:Weight-Bearing / Q000502:physiology*