title: Different incidences of knee arthroplasty in the Nordic countries.
abstract: Background and purpose - The annual number of total knee arthroplasties (TKAs) has increased worldwide in recent years. To make projections regarding future needs for primaries and revisions, additional knowledge is important. We analyzed and compared the incidences among 4 Nordic countries Patients and methods - Using Nordic Arthroplasty Register Association (NARA) data from 4 countries, we analyzed differences between age and sex groups. We included patients over 30 years of age who were operated with TKA or unicompartmental knee arthroplasty (UKA) during the period 1997-2012. The negative binomial regression model was used to analyze changes in general trends and in sex and age groups. Results - The average annual increase in the incidence of TKA was statistically significant in all countries. The incidence of TKA was higher in women than in men in all 4 countries. It was highest in Finland in patients aged 65 years or more. At the end of the study period in 2012, Finland's total incidence was double that of Norway, 1.3 times that of Sweden and 1.4 times that of Denmark. The incidence was lowest in the youngest age groups (< 65 years) in all 4 countries. The proportional increase in incidence was highest in patients who were younger than 65 years. Interpretation - The incidence of knee arthroplasty steadily increased in the 4 countries over the study period. The differences between the countries were considerable, with the highest incidence in Finland. Patients aged 65 years or more contributed to most of the total incidence of knee arthroplasty.
authors.affiliation: a Coxa Hospital for Joint Replacement , Tampere.
authors.forename: Mika J
authors.initials: MJ
authors.lastname: NiemeläInen
authors.affiliation: b Department of Orthopaedics and Traumatology , Turku University Hospital , Turku , Finland.
authors.forename: Keijo T
authors.initials: KT
authors.lastname: MäKelä
authors.affiliation: c The Swedish Knee Arthroplasty Register, Department of Orthopedics , Skåne University Hospital, Lund, and Department of Clinical Sciences, Orthopedics, Lund University , Lund , Sweden.
authors.forename: Otto
authors.initials: O
authors.lastname: Robertsson
authors.affiliation: c The Swedish Knee Arthroplasty Register, Department of Orthopedics , Skåne University Hospital, Lund, and Department of Clinical Sciences, Orthopedics, Lund University , Lund , Sweden.
authors.forename: Annette
authors.initials: A
authors.lastname: W-Dahl
authors.affiliation: d The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery , Haukeland University Hospital , Bergen.|e Department of Clinical Medicine , University of Bergen, Haukeland University Hospital , Bergen , Norway.
authors.forename: Ove
authors.initials: O
authors.lastname: Furnes
authors.affiliation: d The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery , Haukeland University Hospital , Bergen.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Fenstad
authors.affiliation: f Department of Clinical Epidemiology , Aarhus University Hospital, Aarhus, and the Danish Knee Arthroplasty Registry.
authors.forename: Alma B
authors.initials: AB
authors.lastname: Pedersen
authors.affiliation: g Department of Orthopaedic Surgery , Naestved Hospital , Denmark.
authors.forename: Henrik M
authors.initials: HM
authors.lastname: Schrøder
authors.affiliation: h School of Health Sciences , University of Tampere , Tampere , Finland.
authors.forename: Heini
authors.initials: H
authors.lastname: Huhtala
authors.affiliation: a Coxa Hospital for Joint Replacement , Tampere.
authors.forename: Antti
authors.initials: A
authors.lastname: Eskelinen
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000639:trends*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D012086:Reoperation / Q000639:trends; D012537:Scandinavian and Nordic Countries; D017678:Sex Distribution