Total knee replacement: international differences in frequency and surgical technique

Countries  vary  considerably  in  the  number  of  cases  in  which  artificial  knee  joints  are employed, according to researchers from the Medical University of Graz (Austria) reporting at the EFORT Congress in Istanbul.

Istanbul, 6 June 2013  – “Not only does the rate of knee replacement per inhabitant vary from country to country, so too do the types of procedures,” said Dr Patrick Sadoghi (Graz University  Hospital  for  Orthopaedics  and  Orthopaedic  Surgery,  Austria)  summing  up  the data   from   an   international  comparison   study   at   the   14th    Congress   of   the   European Federation of National Associations of Orthopaedics and Traumatology (EFORT) in Istanbul. About 7,500 experts are currently discussing the latest developments in their field.

As the largest joint in the human body, the knee is frequently affected by degenerative joint disease.  In  this  painful  condition,  cartilage  wear  progresses  due  to  wear  associated  with aging, misload of the joint, injuries or other causes and can no longer be repaired once non- surgical  therapies  are  exhausted.  When  joint  preservation  measures  fail,  a  knee replacement   procedure   has   to   be   undertaken.   The   surgeon   does   a   partial   or   total replacement of the joint surface depending on the findings. The service life of the implant is monitored in follow-up checks to detect when prostheses have to be changed, for example. National arthroplasty registers have been set up in many countries to ensure quality control and to determine how well an implant performs. The purpose of these registers is to collect data  on  implanted  prostheses,  e.g.  make  and  model  of  the  implant  and  bone  cement,  as well as follow-up procedures.

Surgery rates vary  between 40 and  163  procedures per  100,000 inhabitants

For  the  evaluation  presented  in  Istanbul,  the  researchers  analysed  data  from  eleven relevant national or regional registers, which provide sufficient information about the procedure and replacement rates of knee prostheses as well as the age of the patients. The comparison  shows  that  the  individual  countries  differ  greatly  in  the  number  of  first-time knee replacements undertaken per year. Dr Sadoghi, author of the study: “The rate varies between 40 and 163 procedures per 100,000 inhabitants, the average being 106.” Amongst the countries being compared, total knee replacement is undertaken most frequently in England,  Denmark,  Norway  and  Sweden  in  relative  terms  and  least  frequently  in  New Zealand, Australia and Canada.

There are also clear-cut fluctuations in the manner in which the prosthesis is fixed in place. The  percentage  of  artificial  knee  joints  fixed  in  place  solely  with  cement  is  90%  in  New Zealand, for example, and only 54% in Australia. There is even greater variation in the way in   which   the   surface   of   kneecaps   is   replaced.   In   Denmark,   72%   of   all   total   knee replacement procedures involve replacement of the back side of the kneecap in which the cartilage in the knee cap is replaced. In Norway, this figure is just 2%.

Economy and  demography as important factors

Scientists attribute these differences to national preconditions, amongst other factors. Dr Sadoghi explained: “On the one hand, health care systems are never identical and on the other hand, the insurance status of the people affected may have an impact, as might the fact that physicians show tendencies in treatment typical of their respective country.” The frequency  of  surgery  is  not  an  indicator  of  the  quality  of  a  health  care  system.  After  all, there  is  great  medical  leeway  with  knee  osteoarthritis,  allowing  alternative  treatment options to be utilised for a long time before an operation becomes unavoidable. Dr Sadoghi: “Endoprostheses  are  highly  cost-intensive,  so  the  use  of  this  approach  is  ultimately  a question of funding.”

Demography may also play a part in the large range of results. Dr Sadoghi: “Psychological strain varies from country to country, as does life expectancy and even the demands people place on their musculoskeletal system. The respective age distribution is another important factor.  It  can  cause  the  additional  financial  burden  to  rise  to  such  an  extent  that  the indication for the surgical procedure is handled differently and quite a bit more restrictively if resources are scarce.”


The   European   Federation   of   National   Associations   of   Orthopaedics   and   Traumatology (EFORT) is the umbrella organisation linking Europe´s national orthopaedic societies. EFORT was founded in  1991 in  the Italian Marentino. Today it  has 42 national member societies from 43 member countries and six associate scientific members.

EFORT   is   a   non-profit   organisation.   The   participating   societies   aim   at   promoting   the exchange  of  scientific  knowledge  and  experience  in  the  prevention  and  treatment  of diseases and injuries of the musculoskeletal system. EFORT organises European congresses, seminars, courses, forums and conferences. It also initiates and supports basic and clinical research.

Source:  EFORT  Abstract  3802:  Epidemiology  and  surgical  technique  of  total  knee  arthroplasty:  a  comparative analysis using worldwide knee arthroplasty registers

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