Trends in comorbidities and complications among patients undergoing elective total hip and knee arthroplasty in the USA.

Background: Demand for total hip and knee arthroplasty procedures continues to rise. Ongoing changes in surgical care and patient populations require continued monitoring of outcome trends. Using nationwide data from the USA, we aimed to describe updated trends in patient and peri-operative care characteristics as well as complications among total hip and knee arthroplasty recipients.

Methods: We included patients who underwent elective primary total hip or knee arthroplasty between 2016 and 2021. Trends were reported for a variety of patient and peri-operative care characteristics as well as complications.

Results: We identified significant trends in patient and peri-operative care characteristics as well as the incidence of complications. While patient median age increased, demographic composition remained consistent over the time period studied. There was a shift towards outpatient total hip and knee arthroplasty procedures, with one in five performed in the outpatient setting in 2021; the median duration of hospital stay decreased by 1 day over the time period for both procedures. Parallel increasing trends of total procedure numbers were found for patients without comorbidities and those with ≥ 3 comorbidities. Postoperative mortality increased significantly over the time period analysed for patients having total hip arthroplasty but not those having total knee arthroplasty (0.08 to 0.15 events per 1000 inpatient days, p = 0.037 and 0.09 to 0.33 events per 1000 inpatient days, p = 0.149, respectively).

Discussion: Compared with previous trend analyses of patients having total hip or knee arthroplasty, the present study shows: an increasing rate of outpatient surgeries; increasing numbers of arthroplasty procedures in high comorbidity burden groups; and an increase incidence of certain serious postoperative complications.