GLOBAL IMPROVEMENT OF TOTAL KNEE RESULTS

 

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On this page we will compare the results of total knee replacement operations done under two different periods: The "old group" are operations done before the 1990's; the "modern group" are operations done in the 1990's. Hopefully, we will be able to demonstrate that there is a progress, that the survival of total knees is improving with the development of new techniques and new models of total knee devices.

We will use the results of total knee replacements as published by surgeons from the whole world. Thus, we hope that what we will see could be called global improvement.

   

       

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TEN-YEAR SURVIVAL OF SWEDISH TOTAL KNEE REPLACEMENTS - THE RESULTS ARE IMPROVING since 1976

 

In the last report from the Swedish total hip register ( 2007) there are data showing how many percent of total knees survived well ten years in the patient's knee. The data comprise practically all patients operated on in Sweden since 1976. For better overview of the following diagram the patients are grouped in five groups according to the operation year. The first group are those operated on in 1976-80, the follow those operated on in 81 - 1985, followed by those operated in  86 - 1990, in 81 - 95, and the last group operated on in 96 -2000.

 

Picture: Diagram showing successive improvement of results of total knee replacement operations since 1976 in Sweden. Every bar represents the results of all patients operated on in the respective five-year period, starting with the period from 1976 through to 1980.  Trend line is put into the diagram.

 

The percentage of total knee devices that survived intact in patients' knees is shown as staples for successive five years periods. For assessing the trend, a trend line is put into the diagram.

This trend line demonstrates that since the years 1976 -1980, the period when the registration of results started, the results of total knee replacement improved considerably. From total knees operated on in that period 16% failed and only 84% survived ten years after surgery.

Twenty years later, from the total knees operated on in the period 1996- 2000, only 4% failed and 96% survived ten years.

The trend line has a bent character. Its shape tells that early after the start of these operations, many better methods and total knee devices were developed, which resulted in quick improvement of results during the early years (from 1976 through to about 1990) of operation activity. With time it became more difficult to invent successful new methods and new total knee device; this fact made the improvement of results during the last ten years (from 1990 through to 2000) much slower.

Note, however: These results apply for the patients operated on for osteoarthritis of knee joint with total knee. For patients operated on with so called unicompartmental replacement, the improvement is not so marked,  actually almost not perceptible all. (Therefore I do not show the diagram).