Early Mortality After Total Hip Arthroplasty In Sweden

Every year 16 000 individuals receive a total hip arthroplasty (THA) in Sweden. Even though THA is a common procedure, adverse events do occur. The most dramatic complication is death in the postoperative phase. The overall aim of this thesis was to describe and investigate early mortality after THA in Sweden. Sweden has an ideal platform for national observational registry studies, thanks to the use of personal identity numbers. Operation-specific information was collected from the Swedish Hip Arthroplasty Register, medical information from the National Board of Health and Welfare, and socioeconomic information was collected from Statistics Sweden. Main outcome was 90-day mortality. Study I was a prospective observational register study investigating the risk of mortality after a simultaneous bilateral THA compared with staged bilateral THA. There was no clinically relevant difference in early postoperative mortality between the two groups. Studies II and III were nation-wide matched cohort studies, with adjustment for comorbidity and socioeconomic background. Adjusted early mortality in femoral neck fracture patients receiving a THA is about double compared with a matched control population. Young (60-69 years) femoral neck fracture patients receiving a THA have a low absolute mortality risk, while those who are older than 80 years with a higher degree of medical comorbidity run a high risk of early death (II). In study III healthier, younger patients with higher socioeconomic status tended to be selected for cementless THA, resulting in selection bias. Even after accounting for this bias, however, there remains a small absolute and adjusted increase in the risk of death within 14 days after elective THA surgery using fully cemented implants. Study IV was a nationwide prospective cohort study comparing different comorbidity measures in terms of predicting early postoperative mortality after THA. A less data-demanding comorbidity measure is better at predicting 90-day mortality than more commonly used coding algorithms. In conclusion, socioeconomic background and the presence of comorbidities have an important influence on early mortality after THA, while the type of fixation is of less importance. Future mortality studies could benefit from the use of data that are routinely collected, and thus avoid the logistically complicated procedure now necessary to merge national databases.