Most research after total knee replacement (TKR) reports knee function one or two years after surgery. These authors wanted to see how the replacement knees fared over a longer time. They checked on patients’ knee function for seven years after TKR. They also wanted to see how patients’ health affected knee function.
Sixty-four patients were followed. They all had the same type of joint replacement, done in the same way. The patients’ average age was 65. Almost 85 percent of them had problems only in one knee. About five percent had problems in both knees. The other 11 percent had other health problems, such as arthritis in other joints.
Results showed much better function over the whole seven years compared to pre-surgery scores. The overall function decreased from the first year after surgery to the seventh year, but not by much. However, patients who had other health problems saw their knee function decline much more than the average.
Also, over the course of the study, many patients became reclassified as having health problems. Only 11 percent had other health problems at the time of surgery. Seven years later, 31 percent of the patients were in that group. The authors also found that women had much lower function scores both before and after TKR. The authors don’t know why. Age and weight at the time of surgery did not seem to be related to function.
This study reminds doctors that knee function declines over time. It also reminds doctors that aging and other health problems can affect knee function. The authors note that it is important to consider health ratings in studies of TKR outcomes.