Insertions of primary knee prostheses – contacts per 1,000 inhabitants, 50 years and older
Discussion
For patients aged 50 and older, 5,857 knee prostheses were implanted in 2015, increasing to 8,814 in 2025. This corresponds to a 50% increase. There was a slight decline in the number of surgeries in the pandemic year 2020. After the pandemic, the level has been higher than before. The figures include both total and partial knee prostheses. The proportion of partial prostheses has shown a steady increase over time.
There is geographic variation in surgery rates. In the catchment areas with the highest rates, more than twice as many surgeries per 1,000 inhabitants are performed compared with the areas with the lowest rates. In 2025, the rate ranged from 2.8 in the catchment area associated with Lovisenberg to 5.3 in Nordland. The proportion of total versus partial prostheses varies considerably between the different catchment areas. In 2025, the share of patients receiving a partial prosthesis ranged from 4% in Finnmark to nearly 34% in UNN and St. Olav.
Women undergo surgery to a greater extent than men, and women accounted for 56% of procedures in 2025. Among patients aged 50 and older, the average age at surgery was similar for both sexes in 2025, at around 70 years.
The analysis is based on activity data from the Norwegian Patient Register (NPR) for somatic specialist healthcare services. The data includes activities in public hospitals and private hospitals providing publicly funded services.
The selection includes contacts registered with one or more of the following six procedure codes::
- Partial prostheses - NGB0, NGB1
- Total prostheses - NGB20, NGB30, NGB40, NGB99
The place of treatment is divided into three categories:
- Local public, treated at one of the hospitals in the catchment area
- Other public, treated at a public hospital outside the catchment area
- Private, treated by a private hospital
Knee prosthesis implantation is performed primarily on patients aged 50 and older. The population therefore includes only these patients. Approximately 200 surgeries are performed annually on patients under the age of 50, most of whom are between 40 and 49 years old.
In order to compare the catchment areas and between years, the rates have been adjusted for gender and age. The adjustment was done using the direct method with the countrys population in 2023 as the reference population.
In graphs with patient‑aggregated data, the numbers are adjusted to avoid double‑counting patients. The actual number of patients is therefore higher when looking at a single variable for a focus area. For example, patients who have received both private and public treatment during a year are counted only once in total, which means that the number of patients in private treatment will be underreported.
SKDE is solely responsible for the interpretation and presentation of the data provided by NPR. FHI/NPR is not responsible for analyses or interpretations based on the data.