title: Biomechanical analysis and quantitative analysis of bone scintigraphy on thrust plate hip prosthesis.
abstract: BACKGROUND
  To study the load distribution of the thrust plate hip prosthesis (TPP, Sulzer Medica, Baar, Switzerland) on femoral bone, a TPP insertion group and intramedullary cemented stem insertion group were prepared with the use of embalmed femoral anatomic specimens, and strain on the femoral bone induced by loading was measured.
  
  
  METHODS
  Bone scintigraphy was performed in 26 joints which underwent total hip arthroplasty with the use of TPP, to enable quantitative evaluation of postoperative remodeling of the bone.
  
  
  RESULTS
  In the TPP insertion group, the strain was almost equivalent to that in the untreated femoral control group. On the other hand, compared with the control group and TPP insertion group, strain in the proximal portion of the femoral bone (medial side of the femoral neck) was significantly smaller in the cemented stem group (control group versus cemented stem insertion group, p=0.0062; cemented stem insertion group versus TPP 130 degrees insertion group, p=0.0005; cemented stem insertion group versus TPP 140 degrees insertion group, p=0.0031). Bone scintigrams revealed decreased uptake at 12 weeks after operation compared with 6 weeks after operation, indicating that TPP allows earlier implant stabilization than the conventional stem.
  
  
  CONCLUSIONS
  Compared with the conventional stem, TPP is a prosthesis that can perform physiological load transmission.
authors.affiliation: Department of Orthopaedic Surgery, Hiroshima Prefectual Akitsu Hospital, 4388 Akitsu Ohaza Mitsu, Toyota, 729-2402 Hiroshima, Japan. toshihiko0416@topaz.ocn.ne.jp
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Goto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yasunaga
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takahashi
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ochi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods; D001696:Biomechanical Phenomena; D001843:Bone Cements; D001860:Bone Plates; D002102:Cadaver; D016022:Case-Control Studies; D019245:Compressive Strength; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging*; D006621:Hip Joint / Q000000981:diagnostic imaging; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical
chemical_list: D001843:Bone Cements