To estimate the lifetime risk of total knee replacement surgery (TKR) including unicompartmental knee replacement surgery (UKR) for osteoarthritis (OA) in New Zealand, and to identify if lifetime risk is changing over time.
Data on primary TKR procedures performed for OA from 2000 to 2015 in New Zealand was obtained from the New Zealand joint registry. Life tables and population data were sourced from Statistics New Zealand and the Ministry of Health of New Zealand. Lifetime risk of TKR was calculated for each year from 2000 to 2015 using registry population data and life tables.
The overall lifetime risk of TKR in New Zealand increased markedly from 2000 to 2015, with females having an overall greater lifetime risk increasing from 9.4% in 2000 to 16.8% in 2015, a relative increase of 78%. However, males showed the greatest increase in risk from 8.1% in 2000 to 16.0% in 2015, a relative increase of 97%.
Current lifetime risk of knee replacement in New Zealand is approximately one in six for males and females. This lifetime risk has increased significantly from 2000 to 2015. These results can be used to guide public health policy planning and division of public health resources.