A total knee replacement is a surgical procedure to replace a severely damaged knee joint with a prosthetic implant. It is now offered routinely for people whose knees are so badly affected by arthritis or injury that they find it difficult to perform day-to-day tasks or move around without pain. Knee replacement is a common form of surgery – according to The National Joint Registry there are around 160,000 total hip and knee replacements in England and Wales each year.
In this blog we consider whether obesity has a detrimental impact on the outcomes of total knee replacement surgery, in the light of a recent study by researchers in The Netherlands, published in the journal The Knee.
What is a total knee replacement?
A total knee replacement involves removing the entire damaged knee joint and replacing it with an artificial joint. You may also hear the term ‘partial knee replacement’ which means removing only the medial (inside) or lateral (outside) compartments of the knee and replacing this with artificial components, rather than replacing the entire joint. If your orthopaedic surgeon believes that you may be better suited to a partial rather than a total knee replacement this will be discussed with you.
There are pros and cons to each type of surgery. While partial knee replacement is a less invasive procedure with faster recovery times and a lower risk of complications, it also carries a higher risk of requiring revision surgery, which means surgery at a later date to replace prosthetic components that have failed. We take great care to explain the pros and cons of each approach to our patients to help them make an informed decision.
Does obesity affect the outcome of total knee replacement surgery?
While the number of people undergoing total knee replacements is rising consistently, so too are obesity rates. Experts predict a doubling in the prevalence of obesity in most European countries by 2030.
Research study
Researchers at the Department of Orthopaedic Surgery in Hoofddorp in the Netherlands wanted to determine whether there was a link between patients with a higher preoperative body mass index (BMI) and rates of revision surgery in the short-term following a total knee replacement.
They looked at data from the Dutch Arthroplasty Register, assessing total knee replacements in patients over 18 years of age with a registered BMI. They compared patients who were not obese with those who were overweight (BMI 25-30) and those who were categorised as class I-III obese (BMI of over 30, over 35 and over 40).
The researchers found that revision rates for non-obese patients were 3.3%. For overweight patients the figure was 3.5%. In patients categorised as obese, revision rates rose steadily according to the class of obesity. For class I obese patients it was 3.7%, for class II 3.6% and for class III 3.7%. They also found that class III obese patients had a significantly higher chance of requiring revision surgery due to infection and class I obese patients had a higher risk of needing secondary patellar resurfacing. The researchers concluded that surgeons should advise their patients of these risks prior to surgery and encourage them to lose weight before the procedure.
How we can help you
If you are considering a total knee replacement and are concern about your weight or if you would like to discuss the impact of weight on outcomes, please contact us. We are accustomed to working with patients for whom this may be an issue and can factor it into your treatment plan. If necessary, we can advise on professional support to help you lose weight before your procedure.
