Thanks for the question which I think is a good one. Often patients who ask this question are answered with a barrage of statistics and percentages which is confusing.
As someone whose mother recently underwent a total knee replacement (TKR) I understand that what patients are really looking for in a surgeon when they ask this question, is someone who can
- do the best surgery possible,
- communicate and empathise well, and
- will care for their family member as if they were their own, which is something I strive for.
The short answer to your question is that – yes, total knee replacement surgery is generally safe, but it depends upon the person having surgery.
Every human being is different and reacts differently to an operation. If your father has a lot of underlying medical problems then that may increase his risk of complications during and after surgery. That is why it is important to find a doctor who treats your father as an individual, rather than having a ‘one size fits all’ approach.
A good doctor will take a careful history asking about underlying medical problems, and perform a thorough examination, not just on the knee, but also of the heart, lungs and abdomen if relevant.
He or she should be able to take the time to explain the procedure and potential complications in understandable language, as well as answer your and your father’s questions. This is the ideal scenario, but I understand that in a busy clinic sometimes it can be difficult for doctors to do so.
MEDICAL COMPLICATIONS AND RISK ASSESSMENT
Before your surgery, your surgeon and anaesthetist should make a risk assessment of your father’s fitness for surgery and may decide whether he is a normal healthy patient, or someone who has a mild/severe disease.
They will look at any underlying medical problems related to each organ system – e.g. heart, lungs, blood vessels, liver, and may organise further investigations and refer to a particular specialist if there is a problem.
Once all medical problems have been addressed, the anaesthetist will discuss with your father what he thinks is the safest anaesthetic to use. In the operating theatre many precautions are taken to minimise risk of infection.
After the surgery your father will be given antibiotics via a drip, and measures will be taken to reduce his risk of developing a ‘blood clot’ in his legs or lungs. He will be given strong painkillers which may enable him to stand and walk immediately after the procedure. If your father is at higher risk of complications then he may be observed closely in a High Dependency Unit (HDU) overnight.
With regards to specific complications, infection is perhaps the most feared complication following TKR.
Fortunately the rate of deep joint infection following TKR is low (less than 1%). There are many risk factors for infection, and a good surgeon will try and control/optimise these factors to reduce risk of infection.
A recent study from Cornell University in the USA1 looked at nearly 18000 patients undergoing TKR and the risk factors for infection. They found that patients with liver, lung or kidney disease, undergoing blood transfusion or having a urine infection in hospital increased the risk of joint infection.
Diabetes mellitus, rheumatoid arthritis, smoking, obesity have also all been identified as potential risk factors for joint infection and should be addressed prior to surgery.
A blood clot in the deep veins of the legs is called a deep vein thrombosis or “DVT” and can occur following a surgical procedure such as a TKR. Rarely, a DVT can travel to the lungs and form a “PE” or pulmonary embolism which can be life threatening.
Fortunately PE’s are not common and occur in only around 1% of patients. The risk of DVT and PE can be reduced through the use of certain ‘blood thinning’ medicines and/or mechanical devices such as foot pumps. Early walking and mobilisation following surgery may also be important, which is why I prepare my patients to walk immediately following surgery and avoid resting in bed for long periods.2
If a patient has liver disease, low platelet count (cells that help the blood clotting process), or clotting abnormalities, then they will be at higher risk of bleeding following surgery and may need a blood product transfusion.
Some patients are already on blood thinning medicine such as clopidogrel or warfarin and will need to stop these 10-14 days before surgery. If your father is a follower of TCM then he should avoid taking TCM herbal medicine for at least 2 weeks prior to any operation.
Cordyceps (冬虫夏草) in particular may increase risk of bleeding. Other Chinese herbs which have blood thinning effects include Szechwan lovage rhizome (chuanxiong), radix salviae miltiorrhizae (danshen), safflower (honghua), red peony root (chishao) and motherwort herb (yimucao).
In summary, total knee replacement is a very common and effective surgery performed worldwide to replace worn out joints, and is generally safe and well tolerated. As each person has a different medical history and response to surgery, its best to find a surgeon who will treat your father as an individual and not take a ‘one size fits all’ approach.
Complications can never be completely eliminated, but with a careful risk assessment and modern techniques, they can be minimised. I hope all goes well with your Father’s operation, thanks for asking your question.
Dr Alan Cheung