Long-term mortality and causes of death among patients with a total knee prosthesis in primary osteoarthritis

Short and midterm mortality of patients with osteoarthritis (OA) who have undergone total knee arthroplasty (TKA) is generally lower than that of the general population. Due to an increasing number of young patients who undergo TKA the expected lifetime of these patients is increasing. The purpose of this study was to assess the causes of death and long-term mortality among Finnish TKA patients.

Standardized mortality ratios (SMRs) for total and site specific causes of death were calculated for 9443 TKA patients operated on in 1980 to 1996 for OA and followed until 2012.

The mean follow-up time was 14 years (maximum 33 years). During follow-up, 77% of the patients had died. The all-cause SMR was 1.00. It was significantly lower than in the reference population (SMR 0.73) during the first 10 years after operation, but higher during the next 10 years (SMR 1.23), and even more after 20 years (SMR 1.95). The SMR for cardiovascular mortality was 1.03 and accounted for 52% of all deaths. Significant excess mortality was observed in diseases of the digestive tract (SMR 1.29). Deaths due to cardiovascular diseases, Alzheimer’s disease and dementia comprised 68% of all deaths that took place 10 years or later after TKA.

The mortality of TKA patients with OA is significantly reduced during the first 10 postoperative years but exceeds the mortality of the general population after that. This trend should be taken into account when young patients undergo a TKA.

Observational study, III.