Multinational comprehensive evaluation of the fixation method used in hip replacement: Interaction with age in context

Background: Fixation in total hip replacements remains a controversial topic, despite the high level of its success. Data obtained from major orthopaedic registries indicate that there are large differences among preferred fixation and survival results. Methods: Using a distributed registry data network, primary total hip arthroplasties performed for osteoarthritis from 2001 to 2010 were identified from six national and regional total joint arthroplasty registries. A multivariate meta-analysis was performed using linear mixed models with the primary outcome revision for any reason. Survival probabilities and their standard errors were extracted from each registry for each unique combination of the covariates. Fixation strategies were compared with regard to age group, sex, bearing, and femoral-head diameter. All comparisons were based on the random-effects model and the fixed-effects model. Results: In patients who were seventy-five years of age and older, uncemented fixation had a significantly higher risk of revision (p <0.001) than hybrid fixation, with a hazard ratio of 1.575 (95% confidence interval, 1.389 to 1.786). We found a similar, if lesser, effect in the intermediate age group of sixty-five to seventy-four years (hazard ratio, 1.16 [95% confidence interval, 1.023 to 1.315]; p = 0.021) and in the younger age group of forty-five to sixty-four years (hazard ratio, 1.205 [95% confidence interval, 1.008 to 1.442]; p = 0.041). There were no significant differences between hybrid and cemented bearings across age groups. Conclusions: We conclude that cementless fixation should be avoided in older patients (those seventy-five years of age or older), although this evidence is less strong in patients of intermediate and younger ages.