The Proportion of Perioperative Mortalites Attributed to Cemented Implantation in Hip Fracture Patients Treated by Hemiarthroplasty

INTRODUCTION: Bone cement for fixation of prostheses, comorbidity and age have been previously shown to be associated with increased relative risk of mortality within the first day of surgery. However, the proportion of mortalities associated to each of these exposures is not adequately expressed by relative risk estimates. MATERIALS AND METHODS: The attributable fraction (AF), i.e. the fraction of diseased individuals attributed to a given risk factor, was estimated for cemented fixation of hip prostheses in the elderly (>65 years) with a hip fracture. Dementia, symptomatic comorbidity (American Society of Anesthesiologists (ASA)≥ 3), old age (≥85 years), male gender, and a delay of 24 hours or more from fracture to operation were considered as additional risk factors for a fatal outcome in close proximity to surgery. RESULTS: In the entire study population (n = 11210), the unadjusted and adjusted population AFs of cemented fixation on mortalities within the first day after surgery were 0.58 (95% CI 0.28-0.76) and 0.59 (95% CI 0.29-0.76), respectively. Symptomatic comorbidity and old age as risk factors had population AFs of 0.71 (95% CI 0.51-0.83) and 0.55 (95% CI 0.39-0.67), respectively. Male gender, dementia and time from fracture to operation all had considerably lower population AFs. CONCLUSIONS: The estimated AFs on perioperative mortality in hip fracture patients treated by hemiarthroplasty showed that about half of the mortalities within the first day of surgery could be associated with the use of bone cement.