title: High protracted (99m)Tc-HDP uptake in synthetic bone implants - a potentially misleading incidental finding on bone scintigraphy.
abstract: We report the case of a 56-year-old male with bilateral total knee prostheses suffering from bilateral knee pain mainly on the right side and referred for bone scintigraphy. The medical history of the patient revealed an opening wedge high tibial osteotomy performed nine years earlier, with insertion of two blocks of ceramic made of hydroxyapatite and tricalcium phosphate in a wedge configuration as synthetic bone substitutes. The porous structure of these implants is analogous to the architecture of cancellous bone and permits fibrovascular and bone ingrowth, promoting the healing process. Planar scintigraphy and SPECT/CT showed an intense uptake within those implants in the early phase as well as in the late phase of the bone scan. It also showed bilateral patellofemoral arthritis. A (99m)Tc-labeled antigranulocyte antibody scintigraphy was negative for infection or inflammation. Bilateral patellar resurfacing led to complete symptom regression, confirmed at 10 months follow-up. To the best of our knowledge, this scintigraphic pattern with such a high tracer uptake reflecting bone substitute osteointegration has not yet been published. This should be considered in patients with such bone replacement materials that are increasingly used, in order to avoid false diagnosis of inflammation or infection.
authors.affiliation: Service de Médecine Nucléaire, Hôpitaux Universitaires de Genève, rue Gabrielle-Perret-Gentil, 4, CH-1211 Genève, Switzerland. Electronic address: Claire.TabouretViaud@hcuge.ch.
authors.forename: Claire
authors.initials: C
authors.lastname: Tabouret-Viaud
authors.affiliation: Service de Médecine Nucléaire, Hôpitaux Universitaires de Genève, rue Gabrielle-Perret-Gentil, 4, CH-1211 Genève, Switzerland.
authors.forename: Ismini
authors.initials: I
authors.lastname: Mainta
authors.affiliation: Service de Radiologie, Hôpitaux Universitaires de Genève, rue Gabrielle-Perret-Gentil, 4, CH-1211 Genève, Switzerland.
authors.forename: Sana
authors.initials: S
authors.lastname: Boudabbous
authors.affiliation: Service de Médecine Nucléaire, Hôpitaux Universitaires de Genève, rue Gabrielle-Perret-Gentil, 4, CH-1211 Genève, Switzerland.
authors.forename: Gaël
authors.initials: G
authors.lastname: Amzalag
authors.affiliation: Service de Médecine Nucléaire, Hôpitaux Universitaires de Genève, rue Gabrielle-Perret-Gentil, 4, CH-1211 Genève, Switzerland.
authors.forename: Osman
authors.initials: O
authors.lastname: Ratib
authors.affiliation: Service de Médecine Nucléaire, Hôpitaux Universitaires de Genève, rue Gabrielle-Perret-Gentil, 4, CH-1211 Genève, Switzerland.
authors.forename: Olivier
authors.initials: O
authors.lastname: Rager
authors.affiliation: Service de Médecine Nucléaire, Hôpital Lariboisière, 2 rue Ambroise Paré, 75010 Paris, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Paycha
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D002516:Ceramics / Q000737:chemistry; D006801:Humans; D006882:Hydroxyapatites / Q000737:chemistry; D007719:Knee Joint / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D010019:Osteomyelitis / Q000000981:diagnostic imaging*; D046788:Patellofemoral Pain Syndrome / Q000000981:diagnostic imaging* / Q000209:etiology; D019275:Radiopharmaceuticals; D013669:Technetium Tc 99m Medronate / Q000031:analogs & derivatives*; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D006882:Hydroxyapatites; D019275:Radiopharmaceuticals; C052435:technetium Tc 99m (Sn) hydroxymethylene diphosphonate; D013669:Technetium Tc 99m Medronate
keywords: Bone scintigraphy; Ceramic; Hydroxyapatite; SPECT/CT; Synthetic bone substitutes