Persistent pain after a knee replacement - what’s normal?

A successful knee replacement (knee arthroplasty) puts new surfaces on the end of the thigh bone, in the top of the shinbone and in the majority of cases, on the back of the kneecap as well. These rely on very accurate cuts to make the implant fit appropriately in all different directions.

The all important soft tissues during knee replacement

Potentially even harder and more important is keeping the tension in the soft tissues around the knee, in the right envelope as well. Tendons and ligaments only work if they’re not too loose and not too tight. This is potentially where the real skill of knee replacement lies.

After these have been achieved, it is important that the implants are carefully attached to the bone so that they last for a long time.

What a successful knee replacement feels like

For most patients, knee replacement surgery leaves them with a knee that doesn’t [always] feel completely natural but it alleviates the pain and allows for a good return to function. We’d expect most people to be able to walk easily, play a round of golf, and for the majority of people to be able to ski after knee replacement - with some people able to do activities that are [a little bit] more intense than that.

Dissatisfaction after knee replacement

Unfortunately, around 15% of people worldwide indicate dissatisfaction with their knee replacement. Some of this can be related to complications such as infections, fractures, and early loosenings.

Ongoing stiffness and pain. The most common problem, however, is ongoing pain and/or stiffness. Whilst this can be influenced by aspects of the patient’s preoperative status, a lot of these seem related to subtle mal-position and mal-sizing problems with the knee implants.

So, what are normal levels of pain? Soon after your knee replacement you’ll feel quite a lot of pain. You’ll also notice there is a numb area on the outside of the wound. This is quite normal. You’ll need lots of painkillers and it will take time to get over. Generally, this pain starts to subside by around 4 to 8 weeks after surgery.

Persistent pain. Persistent pain beyond four months after surgery can be a troubling sign and makes it more likely that the knee is going to end up with more pain and problems in the longer-term. This is not guaranteed and there are a good number of people who have pain for eight months or so, and then it seems to settle down.

What to do with persistent issues following knee arthroplasty

If you are suffering with pain and problems after your knee replacement, firstly you should see your knee surgeon and explain the specific issues to them. If you have a physiotherapist who is used to dealing with knee replacement patients, they are often a very good port of call for questions and reassurance as to whether you’re following a normal path to recovery.

Some of the symptoms indicating all may not be normal

Bending the knee. Things that may not be normal would be an inability to bend the knee beyond a right angle by around 6 to 8 weeks.

Instability. Feelings of severe instability of the knee itself, such that you don’t trust it at all when you put it onto the floor - thinking it’s going to give way if you put any weight on it.

Fractures and nerve damage. There are very rare incidences of fractures and damage to nerves which may have severe consequences but these are normally noted in hospital.

Infection. If your knee is very hot, very red and the wound isn’t healing, you should also see your surgeon quickly as this may be a sign of an infection of your joint. If there is an infection, prompt treatment can radically improve outcomes.

Seeking a second opinion

I see lots of patients for a second and third opinion, who’ve had problems within the knee. We begin with taking a history of whether the knee was good to start with and what the specific dysfunction problems are.

We examine the knee and  assess the range of motion and how well the ligaments are working. Plain X-rays of the knee and sometimes the whole legs can be useful. CT scans can give three-dimensional pictures and sometimes MRIs are needed to look for soft tissue problems. In most cases we’ll do blood tests to look for infection and sometimes we need to take samples from inside the knee as well.

An accurate diagnosis and plan

It is very important that we understand what is wrong with the knee before we consider doing revision surgery. Once a diagnosis has been reached, we can discuss whether revision surgery is likely to help. However, there are a few examples where patients’ pain and symptoms are not an awful lot worse than the pain of having a revision knee replacement would be, and we decide not to revise - inspite of mechanical problems with it.

When a revision knee replacement might be necessary

Typical triggers to consider a revision knee replacement would be: worsening symptoms, severe stiffness, unremitting pain that isn’t responding to moderate levels of analgesia, severe loosening of the implants or infection of the implants.

If you’re going to have a revision knee replacement, I would advise that it is done by a revision knee specialist. Ideally this should be somebody doing at the very least 10 revision knee replacements a year, with access to all appropriate instruments, and a clear plan and pathway of how to use them.

Furthermore, if you’re elderly and have other medical problems, surgery should be performed in a hospital with a high dependency intensive care unit, such as the Wellington Hospital.

A word from Compare my Care

Mr Jonathan Miles is a revision super-specialist with a sub-specialty in treating patients with complex health needs. His extensive expertise in these two areas, as clinical lead within the Royal National Orthopaedic Hospital - Stanmore, and privately at The Wellington Hospital place him in high demand across London and further afield. Mr Miles also performs a high volume of primary knee replacements using the MAKO robot.