title: In vivo monitoring of implant osseointegration in a rabbit model using acoustic sound analysis.
abstract: Implant osseointegration can currently only be assessed reliably post mortem. A novel method that relies on the principle of acoustic sound analysis was developed to enable examination of the longitudinal progress of osseointegration. The method is based on a magnetic sphere inside a hollow cylinder of the implant. By excitation using an external magnetic field, collision of the sphere inside the implant produces a sound signal. Custom-made titanium implants equipped thusly were inserted in each lateral femoral epicondyle of 20 New Zealand White Rabbits. Two groups were investigated: Uncoated, machined surface versus antiadhesive surface; and calcium phosphate-coated surface versus antiadhesive surface. The sound analysis was performed postoperatively and weekly. After 4 weeks, the animals were euthanized, and the axial pull-out strengths of the implants were determined. A significant increase in the central frequency was observed for the loose implants (mean pull-out strength 21.1 ± 16.9 N), up to 6.4 kHz over 4 weeks. In comparison, the central frequency of the osseointegrated implants (105.2 ± 25.3 N) dropped to its initial value. The presented method shows potential for monitoring the osseointegration of different implant surfaces and could considerably reduce the number of animals needed for experiments.
authors.affiliation: Department of Orthopedics, University Medicine Rostock, Doberaner Strasse 142, D-18057, Rostock, Germany.
authors.forename: Cathérine
authors.initials: C
authors.lastname: Ruther
authors.forename: Carolin
authors.initials: C
authors.lastname: Gabler
authors.forename: Hartmut
authors.initials: H
authors.lastname: Ewald
authors.forename: Martin
authors.initials: M
authors.lastname: Ellenrieder
authors.forename: Maximilian
authors.initials: M
authors.lastname: Haenle
authors.forename: Tobias
authors.initials: T
authors.lastname: Lindner
authors.forename: Wolfram
authors.initials: W
authors.lastname: Mittelmeier
authors.forename: Rainer
authors.initials: R
authors.lastname: Bader
authors.forename: Daniel
authors.initials: D
authors.lastname: Kluess
mesh_terms: D000162:Acoustics; D000818:Animals; D005260:Female; D023421:Models, Animal; D016348:Osseointegration; D019736:Prostheses and Implants; D011817:Rabbits; D014025:Titanium
chemical_list: D014025:Titanium
keywords: acoustic testing; animal experiment; implant coating; osseointegration; vibration analysis