(openPR) Dutch study: Overweight is a high risk factor for complications in hip and knee replacement -- Experts urge obese patients to reduce weight before surgery
Obesity among those who have had a total hip joint replacement results in a 3.3-fold increased risk of infection and a 1.5-fold increased risk of aseptic loosening. Additionally, the risk of thromboembolism and dislocation almost doubles, experts at the EFORT Congress in Copenhagen report. Further data show a similarly disturbing outcome for total knee replacement. Specialists therefore urge overweight patients to lose weight before surgery.
Copenhagen, 1 June 2011 - Obese patients face significantly greater risks following hip joint replacement than patients of normal weight. Defining obesity as a Body Mass Index (BMI) of over 30, the risk is 3.3 times greater that infection will develop and 1.5 times greater that aseptic loosening will result (mechanical, as opposed to inflammation-induced). Obese patients also face twice as much risk of thromboembolism and artificial joint dislocation. A BMI plus 10 increases the risk by as much as 284%. The data, presented today at the 12th Congress of the European Federation of National Associations of Orthopaedics and Traumatology (EFORT) in Copenhagen, should put an end to the long lasting debate among specialists as to whether or not overweight and obesity influence the clinical outcome and complication rate in arthroplasty.
Increased complication rate in total hip replacement
One source of this insight is a meta-study on the complication rates in total hip arthroplasty that pools 15 smaller studies and covers nearly 10,000 cases. It is the first yielding highly significant statistical result that shows obese patients running substantial health risks in undergoing arthroplasty. "The complications dramatically increased among the obese and were not of a negligible nature." According to Dr. Daniel Haverkamp from the Academic Medical Center in Amsterdam, a leading author of the meta-study, "those complications were themselves quite dramatic. Deep infections or loosening require a replacement of the endoprosthesis in yet another burdensome surgical procedure. In the case of infections which may become chronic, sometimes three or four follow-up surgeries are needed. A dislocation such as the head of the endoprosthesis slipping out of the joint socket is a painful event. And embolisms may end lethally."
Impaired outcome in total knee replacement
A second corroborating source is a new Danish study investigating clinical outcomes of total knee replacement and the patients' quality of life three to five years afterwards. Researchers followed up on all 197 patients who had undergone primary total knee replacement at Denmark's Southern Jutland Hospital in 2005 and 2006. Results were measured by using patient reported outcome (SF-36) and an objective knee score: the Knee Society Clinical Rating System (KSS). "Outcomes drastically worsened with an increase in BMI," Anette Liljensø (Århus University Hospital), leading author of the study, explained at the EFORT Congress. The parameters most affected by obesity were those evaluating physical capabilities, starting with the KSS score which measures walking distance, the ability to climb stairs and the use of assistive technology such as walkers.
With a 5 point increase in the BMI scale, there was a 96% greater risk of exhibiting a lower KSS function score. With a 10 point higher BMI score, the risk increased by 284%. The social function score among the obese proved to be significantly worse as well, since people who cannot get around easily tend to lose their social contacts.
Experts call for weight reduction before surgery
"The data no longer leave room for doubt," Dr. Daniel Haverkamp concludes. "Overweight and obesity are predictive factors for dangerous complications and poor outcome in lower limb joint replacement, and we have to tackle that problem. Obese patients must be informed about these risks and urged to lose weight before surgery. Since only a few will be able to do this sufficiently on their own, we need to refer these patients to specialized institutions."
About EFORT
The European Federation of National Associations of Orthopaedics and Traumatology, EFORT, is the umbrella organisation linking Europe's national orthopaedic associations. It aims at promoting the exchange of scientific knowledge and experience in the field of prevention and both the conservative and surgical treatment of diseases and injuries concerning the musculoskeletal system. It places particular emphasis on education and research.
EFORT was initially established by the national associations for orthopaedics and traumatology from twenty European countries. The Federation was founded in Marentino, Italy, in 1991, thus celebrating its 20th anniversary. Today it has 42 national member societies from 40 member countries, as well as six associate scientific members. EFORT is a non-profit organisation and all funds are used exclusively in the pursuit of the Federation's aims.
