Knee Replacement

Knee Replacement

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Knee replacement

What is a knee replacement?

Knee replacement is a surface change from an arthritic painful one to a plastic and metal surface. It takes the pain away from bad surface of the knee. Any pain coming from other sources such as soft tissues or referred pain from low back or hip does not improve with knee replacement.

Knee replacement is a procedure tougher to go through than a hip replacement. This is largely because the knee is right under the skin, there is not enough soft tissues around the joint so the swelling is a lot more obvious and movements are more hard work than a hip replacement.

The knee surgery scar is in front of the knee and moving it stretches the scar making it more painful and the discomfort continues for a long time (up to 1 year), hence I always tell patients it is hard work. It is a partnership. I can change the joint but you, as the patient, will have to work hard and only then we will have success.

Do I need a knee replacement?

Knee replacement is done for arthritis or surface wear of the knee. Most people gradually have surface wear over the years. It could be early if you have been a sport enthusiast and a damaged knee, or because it runs in your family, or you may have had meniscus damage/surgery (usually old) several years/decades ago, or indeed you have inflammatory arthritis affecting the knee along with several other joints.

Most patients will complain of pain specific to where the arthritis is inside, outside, in front of the knee or all around. The knee will get swollen intermittently, worse after activity or sport. The pain is often a hot pain, sometimes described as a toothache type-pain. When it is bad it can be there all the time and disturbs sleep. Arthritic symptoms often go up and down and people say they have good days and bad days. With time, bad days become more frequent and longer and more severe.

Generally, when the pain is there all time, disturbs your sleep, affects your function and quality of life – it is worth looking at the knee and see if you need a knee replacement.

In the clinic I will talk to you, examine you and usually get X-Ray’s (if not done already) and occasionally an MRI scan of the knee.

The judgment of whether you are at a point where a knee replacement is appropriate is a complex one. It is important to note you make that decision. I can help you and guide you to decide about it.

The main reason for a knee replacement is that it is done for pain from the bad surface of the knee. It is a replacement of the surface. It does not improve pain from anything else.

The complexity of decision to do knee replacement is largely because an artificial knee is a downgrade from a normal knee, and it cannot compete with your original knee. However, when an arthritic knee is so bad that an artificial knee looks like an upgrade, it is time to consider a knee replacement. Sometimes, I will ask you to come back after you have had time to think about it, and discuss with friends and family.

What are alternative treatments for knee replacement?

Knee replacement is not the only option for arthritis of the knee. You can change your lifestyle, consider pain killers, lose weight, and consider using stick/s. Occasionally an injection may help improve the inflammation though it does not change the arthritis. With these non-operative options you can avoid a knee replacement for a period of time.

Physiotherapy often helps to improve things, at least to some extent, and for a period of time.

Glucosamine, other health food /drugs have not proven to work but some people feel better for a period of time (placebo effect).

Acupuncture, other allied treatments can offer pain relief for some patients.

Sadly none of the above treatments actually turn arthritis back to normal knee.

There are smaller surgical options like a clear out of knee with key hole surgery, stem cell treatment, etc. none of them have proven beneficial in an arthritic knee. As yet there is no commercially available surgical treatment that will turn arthritis back to normal knee.

What are the risks and complications of the operation?

There are following risks and complications of the operation

Infection – this is risk with every operation but overall it is less than 1:300.

Bleeding – bleeding bad enough to need blood transfusion is less than 1:100

Injury to nerves or blood vessels – this is rare but devastating complication.

Fracture – again a rare risk.

Thrombosis and embolism – this mean clot in the leg and sometimes it goes to the lung. You will be individually assessed for this risk. You will have stockings and a pump on the leg after the operation, medication like a heparin (LMWH) injection whilst in the hospital and usually Aspirin after discharge from the hospital for 4 weeks if you can tolerate it. These are all measures to stop the clot in leg and reduce the risk, but they can’t eliminate it. Sometimes I will change this if the risk of bleeding or wound leaking is too much.

Medical complications – such as heart attack, chest infection, stroke and confusion exist. They are very much dependent on how fit you are before surgery. If you get it, we treat it.

Fatal complications – rare – generally 1:300 or less. It is important that you are aware of it.

Further surgery – If you have a complication that needs further treatment or if in the long-term if metalwork fails one day and it has to be done again.

Persistent pain – This is because pain coming from anything other than the bad surface or arthritis is not going to be changed by the operation.

Stiffness – As I have mentioned before a knee replacement is hard work on the patient’s part to get it moving especially in for the 6-8 weeks following the procedure. If you cannot do the exercises for any reason, you have a significant risk that it may get stiff with scarring (healing) around the knee. Rarely, I may have to manipulate the knee under anaesthetic if stiffness is severe at a later date.

Scar pain – the scar can be troublesome for some patients.

What do you do in a knee replacement?

In a knee replacement, after anaesthetic, I will apply tourniquet to stop blood flowing down the leg. It improves visibility and reduces blood loss during operation. Rarely, I may not apply tourniquet if suggested by a vascular specialist. After this, I will usually make an up and down straight cut in front of the knee approximately 5 -10 inches (depending on your size). I go through the soft tissues in front of the knee. Rarely the incision may be different if you have old scars around knee.

Then I shave off a bit of cartilage and bone from both surfaces of the knee joint and put in the metal surface on one side and a plastic surface held in a metal tray on the other side. The components are fixed with bone cement (special type of acrylic).

I use an infiltration of painkillers in the wound and also some medicine to reduce bleeding from the tissues before the wound is closed.

Then I will close the wound and you will have clips on the skin. The skin clips stay for 10-14 days and come off in your doctor’s surgery or in hospital. This is arranged by our nurses before you are discharged.

There is a third surface in the knee – the undersurface of the knee cap. Rarely will I change this too. Usually I will reshape it and leave it alone.

What kind of anaesthetic will I have?

The anesthetist will see you soon after admission, assess you and discuss about the anaesthetic choices with you. The anesthetist will explain about the risks and complication as well as benefits of different types of anaesthetic and help you choose the right one for you. Generally you will have a spinal anaesthetic with sedation. Also, often I will use infiltration of painkillers (local anaesthetic) in the wound.

How long is the scar?

The scar for normal knee replacement is generally 5-6 inches for most patients. Occasionally, depending on the size of the patient, it may be longer up to 10 inches. 

How long does it take for the operation?

The operation itself takes around 1 hour in most patients. Occasionally, for a more complicated case, it may take longer up to 1.30 hours. The whole journey however is a lot longer, several hours, going from the ward to the anaesthetic room to the operating theatre to recovery and back to the ward.

When can my family call back to find out if it’s all done or they can come to visit me?

In the morning after we have seen all the patients, the anesthetist, theatre staff and I will meet to discuss how we are going to proceed with the day’s work and decide the order of the cases. If you are going later the nurses will offer you a drink of water until the last moment possible (please do not drink or eat yourself).

Depending on the order of the list, you can ask family to call or visit you.

Generally, most operations finish and all patients are back to the ward by 6pm in an all-day list.

How long will I be in the hospital after surgery?

Most patients are in the hospital for 2-3 nights after the surgery.

How long does it take to recover from the operation?

The first day (24 hours) after operation is not great. Largely because you need painkillers often and so sleep is disturbed. The painkillers can make you feel sick so you can’t eat or drink. It feels rough.

You will start getting more and more comfortable with each passing day after this. The Physio will start getting you up and about from the first day. Initially you will do very little. In the next day or two you will make progress to walk with crutches and will have learnt how to go up and down on stairs before discharge home. The Physiotherapy staff will give you homework until they see you next in the outpatient’s clinic.

The skin clips will come off in 10-14 days and the nurses will arrange this. You can give up using crutches as soon as you are safe, initially indoors and then outdoors.

You will need some help at home for first 2-4 weeks with little things and help with shopping for 4-6 weeks.

There will be Physiotherapy arranged for you within 3-4 weeks after the surgery in the hospital and they will work with you to get the function back.

I will usually see you in clinic at 6-8 weeks after the surgery.

You will continue to make gradual progress with your knee for the first year. It gets a lot better in 3-6 months and then more or less near normal at 1 year. The scar takes up to 12-18 months to mature. 

I have heard about some others who are not happy after this operation – will that happen to me?

There are studies showing 10-20% of patients not being happy after a knee replacement. A lot of this is because people’s expectations are not met by the artificial knee. The artificial knee is no match for a normal knee. The main reasons tend to be persistent pain or stiffness. Pain: coming from sources outside the knee such as soft tissues or scar pain. Stiffness: if patients cannot or do not do the Physiotherapy to regain function in the knee after surgery.

When can I start driving?

Generally, most patients start driving after 6 weeks. I cannot certify you either way. You have to make that decision based on your ability to control the vehicle safely.

When can I go back to work?

You can go back to work when you can do your job safely. Generally, most office workers get back to work in 4-8 weeks and manual workers 6-10 weeks. If you have to drive to work you will go back after you can drive safely. It may be possible to get to work sooner if your employer can help you with phased return to work. You should discuss this with your employer.

When can I return to sport?

You can start some sport early such as cycling (static bike), swimming etc. as soon as 4 weeks after the procedure. For hard court games and jogging it could be a lot longer and depends on your recovery and how the physiotherapists feel about your progress. You should always go back slowly and gradually increase your ability over weeks/months.

How long will the knee replacement last?

The knee replacements I use have a good track record with more than 90% survival at 10 years. It is a mechanical devise and eventually it will fail if you live longer or use it more. If it fails it may have to be done again. 

When should I call back the hospital?

Leaking wound – that is not settled or requires dressings beyond 7 days

Infection – as maybe told by GP or practice/community nurse (please do not start antibiotics)

Swelling and calf tenderness – some swelling and tenderness is common after knee surgery because of local tissue bruising. Individually patients are very different and I, as your surgeon, will have explained to you about your likelihood of swelling and bruising in your case. When the swelling and calf pain are unusually bad or indeed you or your GP are concerned, you need a scan to prove this is not a clot in the leg. There is no reliable clinical examination test to rule out clot in leg.

Ashwin Kulkarni FRCS
Consultant Orthopaedic Surgeon
University Hospitals of Leicester
Leicester General Hospital
Gwendoline Road


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