Using data from the Norwegian Hip Fracture Register, 8639 cemented and 2477 uncemented primary hemiarthroplasties for displaced fractures of the femoral neck in patients aged > 70 years were included in a prospective observational study. A total of 218 re-operations were performed after cemented and 128 after uncemented procedures. Survival of the hemiarthroplasties was calculated using the Kaplan-Meier method and hazard rate ratios (HRR) for revision were calculated using Cox regression analyses. At five years the implant survival was 97% (95% confidence interval (CI) 97 to 97) for cemented and 91% (95% CI 87 to 94) for uncemented hemiarthroplasties. Uncemented hemiarthroplasties had a 2.1 times increased risk of revision compared with cemented prostheses (95% confidence interval 1.7 to 2.6, p < 0.001). The increased risk was mainly caused by revisions for peri-prosthetic fracture (HRR = 17), aseptic loosening (HRR = 17), haematoma formation (HRR = 5.3), superficial infection (HRR = 4.6) and dislocation (HRR = 1.8). More intra-operative complications, including intra-operative death, were reported for the cemented hemiarthroplasties. However, in a time-dependent analysis, the HRR for re-operation in both groups increased as follow-up increased. This study showed that the risk for revision was higher for uncemented than for cemented hemiarthroplasties.

The Norwegian Arthroplasty Register was established in 1987. Until January 1994, approximately 200 different implant combinations had been used in total hip replacements (THR) in Norway. About 5,500 THR were performed each year in this period with a total cost of 70 million USD per year. We analyzed the economic consequences related to the use of some inferior primary hip arthroplasties in this period. As the reference arthroplasty, we chose the most commonly used prosthesis in Norway, i.e., the Charnley prosthesis fixed with high viscosity cement containing antibiotic and with systemic antibiotic prophylaxis (n 4,970). We compared this reference group to all other primary THR registered in the same time period (n 24,027), and to the following sub-groups of primary THR: 1) uncemented Ti-Fit/ Bio-Fit (acetabulum/femur) combination (n 173), 2) uncemented Coxa/Femora combination (n 153), 3) THR with low-viscosity cement (n 1,807) and 4) THR with Boneloc cement (n 1,250). We estimated the number of additional revisions compared to the reference arthroplasty after a follow-up of 3-5 years in the different groups, with adjustment for age, sex and diagnosis. The direct extra revision costs were calculated. Compared to the reference arthroplasty, the group of all other primary THR gave an extra revision cost estimated at about 1.7 million USD per year. About 1,000 uncemented Bio-Fit femoral prostheses have been applied in Norway, including those implanted before the registration started (1985-1987). The extra revision costs the first postoperative years for these 1,000 prostheses amount to about 0.7 million USD per year. Corresponding figures in the Coxa/ Femora group were 0.08 million USD, in the group with low-viscosity cement, 0.3 million USD and in the Boneloc group, 0.4 million USD per year.

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