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.