Changes in epidemiological characteristics of knee arthroplasty in eastern, northern and central China between 2011 and 2020

Objective To explore changes in the epidemiological and clinical characteristics of patients who underwent knee arthroplasty (KA) over a 10-year period in China. Methods Medical records of patients with knee osteoarthritis (KOA), who underwent primary unilateral KA in 5 level I center hospitals in China between January 2011 and December 2020, were retrospectively reviewed and analyzed. To more clearly define changes over the years, patients were divided into two groups according to time of admission at 5-year intervals. Age, sex, body mass index (BMI), Kellgren–Lawrence (K–L) classification, comorbid diseases, surgical procedures, hospital stay, and hospitalization costs were compared between the two groups. Results A total of 23,610 patients with KOA (5400 male and 18,210 females; mean age: 65.7 ± 7.6 years) who underwent primary unilateral KA were included. The number of KAs increased in recent years (group A, n = 7606 vs. group B, n = 16,004). Significant differences were noted in age, sex, BMI, K–L classification, comorbidities, surgical procedures, hospital stay, and hospitalization costs between the two periods ( P < 0.05). More than three-quarters of KA cases involved females, and the age at surgery tended to be younger than that reported in foreign countries. In group B, the proportion of overweight and grade III, number of comorbidities, and unicompartmental knee arthroplasty patients increased compared to that in group A; however, hospitalization costs and length of hospital stay decreased. Conclusions Results suggested that the epidemiological characteristics of patients undergoing KA have changed over time. An analysis of the epidemiological characteristics of patients undergoing KA treatment may provide a scientific basis for the prevention and control of KOA.