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Vaccum Mixing of Methylmethacrylate

- Discussion:
          - see 
cement mixing: 
          - in the study by Geiger MH, et al (2001), the authors performed a controlled study compared the strength and porosity of 48 
                  polymethylmethacrylate cement-implant constructs prepared with open bowl versus vacuum mix technique;
                  - 48 blast finished stainless steel rods of 13 mm diameter were implanted with centralizers into 17-mm inner diameter tubes that had been retrograde
                          filled with polymethylmethacrylate cement;
                  - 8 cement preparations used were open bowl and vacuum mixed Simplex, Osteobond, Zimmer Dough Type, or Palacos R;
                  - 6 replications of each condition were performed.
                  - rod pushout data showed there was no significant difference between open bowl and vacuum mixed samples when all cement brands were combined;
                  - mean sheer force for Palacos R vacuum mixed samples was greater than open bowl (634 ± 47 versus 423 ± 171), whereas the force for
                          Zimmer Dough Type cement open bowl was greater than that of the vacuum mixed samples (901 ± 71 versus 705 ± 82);
                  - cycles to failure data did not show significant differences when open bowl and vacuum mixed samples were compared when cements
                          were analyzed individually or combined;
                  - image analysis of cement-implant interfaces showed that vacuum mixing reduced void area significantly compared with open bowl mixing in
                         Palacos R and Osteobond preparations.
                   - vacuum mixing does not appear to reduce cement prosthesis interface porosity or improve its mechanical properties in all cements.
           - references:
                   - The Clinical Significance of Vacuum Mixing Bone Cement
                   - Do we need to vacuum mix or centrifuge cement?
                   - Vacuum mixing of acrylic bone cement.  
                   - Bone cement improved by vacuum mixing and chilling
                   - [Reduction of severe cardiac complications during implantation of cemented total hip endoprostheses in femoral neck fractures]
                   - Transesophageal echocardiography and clinical features of fat embolism during cemented total hip arthroplasty. A randomized study in patients with a femoral neck fracture.
                   - Prophylaxis against fat and bone-marrow embolism during total hip arthroplasty reduces the incidence of postoperative deep-vein thrombosis: a controlled, randomized clinical trial.
                   - Is there a difference in perioperative mortality between cemented and uncemented implants in hip fracture surgery?
                   - Periprosthetic fractures around hip hemiarthroplasty performed for hip fracture.
                   - Cardiac output during hemiarthroplasty of the hip. A prospective, controlled trial of cemented and uncemented prostheses.