title: Effect of pressurization on methylmethacrylate-bone interdigitation: an in vitro study of canine femora.
abstract: Aseptic mechanical loosening of the femoral and acetabular components is a major long term complication of total hip arthroplasty. Pressurized injection of bone cement (polymethylmethacrylate) has been advocated for increasing cement-bone interlock. To determine the relationship between cement intrusion pressure and its penetration into cancellous bone, an in-vitro study of paired, fresh frozen canine femora was conducted. Methacrylate cement was injected at predefined constant pressures from 0.11 to 1.23 MPa (16-175 psi). The penetration was quantified for each injection pressure. The results showed a positive logarithmic relationship between the relative penetration and the intrusion pressure, the former reaching a near asymptotic value at approximately 0.70 MPa (100 psi). Unequal radial distribution of cement within the metaphysis was demonstrated. Greater penetration was observed into the proximal postero-lateral cancellous bone bed as compared to other regions. The relationship between cement penetration and bone size was explored at a single-constant pressure of 0.35 MPa (50 psi). Although absolute cement penetration was found to be linearly related to the bone size, the relative penetration remained nearly constant with bone size.
mesh_terms: D000818:Animals; D001843:Bone Cements / Q000008:administration & dosage*; D004285:Dogs; D005269:Femur; D066298:In Vitro Techniques; D008433:Mathematics; D008768:Methylmethacrylates / Q000008:administration & dosage*; D011312:Pressure
chemical_list: D001843:Bone Cements; D008768:Methylmethacrylates