The National Institute for Clinical Excellence, UK published guidelines in 2007 encouraging the use of low molecular weight heparin (LMWH) joint replacement surgery. Subsequently, our hospital adopted these guidelines in the treatment of total hip replacements. This study is based on our prospective database of total hip replacements between 2005 and 2009 and compares the complication and mortality rates pre- and post institution of the NICE guidelines. We analysed prospectively collected data on 686 patients who underwent a primary total hip replacement done by a single surgeon between January 2005 and April 2009. We compared the incidence of mortality, pulmonary embolism, myocardial infarction and intracranial bleeding between the two groups. Prior to the guidelines, all patients were treated for the duration of their admission with 75mg aspirin followed by 4 weeks after discharge. Subsequent to the guidelines, the treatment changed to 40mg of LMWH (Clexane) while an inpatient with aspirin being prescribed for 4 weeks on discharge. Patients unable to tolerate aspirin were treated with low molecular weight heparin. High risk patients (previous pulmonary embolism, previous deep vein thrombosis, family history) were treated with 6 weeks of warfarin. Each patients was reviewed at 8 weeks and 6 months following surgery, and adverse incidents were documented at each review or incident.
We assessed polyethylene wear and osteolysis in 15 patients (30 hips) undergoing staged bilateral total hip arthroplasty, who had a cemented hip arthroplasty on one side and a hybrid arthroplasty on the other. All factors apart from mode of acetabular component fixation were matched. Wear was measured radiographically using Livermore’s technique. The mean clinical and radiological follow-up was 11.2 years for the cemented arthroplasties and 10.7 years for the hybrid arthroplasties. Mean annual linear wear rate for the cemented cups was 0.09mm/year, and 0.14mm/year for the uncemented cups. This difference was statistically significant (p=0.03), confirming previous reports that polyethylene wear in uncemented cups is greater than in cemented cups. Polyethylene wear in the uncemented cup exceeded wear in the cemented cup by more than >
0.1mm/year in 5 patients, 4 of whom had a BMI of greater than 30. No periacetabular osteolysis was noted. Femoral osteolysis was present in 5 hybrid arthroplasties and 2 cemented arthroplasties. Zone 7 femoral osteolysis occurred in 3 patients on the side of the hybrid arthroplasty, multifocal femoral osteolysis not involving zone 7 was seen in 2 patients in both hips.