Current orthopedic practice requires consideration of apparently contradictory recommendations regarding VTE prevention among THR/TKR patients. American College of Chest Physicians (ACCP) 8th Clinical Practice Guidelines for the Prevention of Venous Thromboembolism recommend against aspirin for VTE prophylaxis in any patient We conducted a prospective observational study among consecutive patients presenting for total hip or knee arthroplasty. Pre-operative PE risk stratification was performed at the discretion of the surgeon. Patients identified as usual risk for PE received aspirin. Patients considered being at elevated risk for PE received warfarin. This observational study protocol called for one year of data collection. At approximately 8 months 656 patients were enrolled, and the surgeon principally implementing PE risk stratification and administration of aspirin chose to stop enrolling patients due to a high incidence of pulmonary emboli. One hundred fifty five patients received thromboprophylaxis with aspirin 600 mg PR in the PACU, then 325 mg BID for one month (reduced to 81 mg daily if GI symptoms were present). The remaining 501 patients received an ACCP-based warfarin protocol managed by a pharmacist anticoagulation management service. Our hypothesis is the null hypothesis; that an AAOS-based approach to hromboembolism prevention is not inferior to an ACCP-based approach. The a priori primary endpoints of the AVP Study are clinically overt VTE, DVT, PE, major bleeding, and death. All patients will receive a 90 day follow-up questionnaire in person or by telephone. Additionally, the electronic medical record of Intermountain Healthcare will be interrogated for ICD-9 codes germane to the outcomes of interest. Ninety day follow-up has been completed for approximately 140 patients. The dataset will be locked upon completion of the 90 day follow-up among those patients who last received PE risk stratification and aspirin therapy (data lock early June, 2009). We anticipate preliminary data available for report by July, 2009.
1. Radiological and histological observations of the tissue changes resulting from the implantation of various metals in the long bones of dogs are recorded. 2. Of the metals employed, tantalum, Vitallium, alloys "C" and "S" and F.M.B. steel were inert; silver and mild steel were reactive; F.S.T. steel occupied an intermediate position. 3. A correlation has been demonstrated between the anodic back E.M.F., the weight loss due to corrosion and the histological changes produced.
1. The literature dealing with the reaction of tissues to metals has been briefly reviewed and discussed. 2. It is suggested that the "anodic back EMF" of metals, under the conditions of the experiment, is a measurable electrical quantity which can be correlated with their behaviour in tissues. 3. Details of the method for obtaining this "anodic back EMF" are given. 4. A correlation between the "anodic back EMF" and the loss of weight due to corrosion 5. The inertness of eighty-seven metals has been classified by this method. 6. It must be emphasised that these results are based on
