We identified a group of patients from the Swedish
Arthroplasty Register who reported no relief of pain or worse pain
one year after a total knee replacement (TKR). A total of two different
patient-reported pain scores were used during this process. We then
evaluated how the instruments used to measure pain affected the
number of patients who reported no relief of pain or worse pain,
and the relative effect of potential risk factors. Between 2008 and 2010, 2883 TKRs were performed for osteoarthritis
in two Swedish arthroplasty units. After applying exclusion criteria,
2123 primary TKRs (2123 patients) were included in the study. The
Knee injury and Osteoarthritis Outcome Score (KOOS) and a Visual
Analogue Scale (VAS) for knee pain were used to assess patients pre-operatively
and one year post-operatively. Only 50 of the 220 patients (23%) who reported no pain relief
on either the KOOS pain subscale or the VAS for knee pain did so
with both of these instruments. Patients who reported no pain relief
on either measure tended to have less pain pre-operatively but a
higher degree of anxiety. Charnley category C was a predictor for
not gaining pain relief as measured on a VAS for knee pain. The number of patients who are not relieved of pain after a TKR
differs considerably depending on the instrument used to measure
pain. Cite this article:
Patients with osteoarthritis undergoing knee replacement have been reported to have an overall reduced mortality compared with that of the general population. This has been attributed to the selection of healthier patients for surgery. However, previous studies have had a maximum follow-up time of ten years. We have used information from the Swedish Knee Arthroplasty Register to study the mortality of a large national series of patients with total knee replacement for up to 28 years after surgery and compared their mortality with that of the normal population. In addition, for a subgroup of patients operated on between 1980 and 2002 we analysed their registered causes of death to determine if they differed from those expected. We found a reduced overall mortality during the first 12 post-operative years after which it increased and became significantly higher than that of the general population. Age-specific analysis indicated an inverse correlation between age and mortality, where the younger the patients were, the higher their mortality. The shift at 12 years was caused by a relative over-representation of younger patients with a longer follow-up. Analysis of specific causes of death showed a higher mortality for cardiovascular, gastrointestinal and urogenital diseases. The observation that early onset of osteoarthritis of the knee which has been treated by total knee replacement is linked to an increased mortality should be a reason for increased general awareness of health problems in these patients.