Arthrisis

Knee ‘osteoarthritis’ is a term for ‘wear and tear’ in the knee. This osteoarthritis is caused when the lining of the knee (articular cartilage) becomes thinner, fragments and wears away. You will be at a higher risk of developing arthritis if you have had a previous injury to your knee, particularly if you have injured ligaments, menisci or articular cartilage in the past.

Symptoms and signs

This classically causes a gradual decline in the function of your knee. Pain and stiffness are key features. You may notice over a long period of time your knee has periods where it improves and then worsens. Sadly the arthritic process will progress so your bad weeks come around too frequently and the good days disappear. The time scale this occurs can vary from person to person secondary to many variables and so is difficult to answer the frequently asked question – ‘When will I need a knee replacement?’

Treatment

Non operative treatment

Initially all treatment should be focussed on educating the patient of their diagnosis and the likely path their knee will walk in the future! Symptom control is key and this can vary on an individual level from anti-inflammatories or painkillers / acupuncture / physiotherapy / weight loss / braces or sticks / steroid injections and viscosupplementation injections.

Operative treatment

Partial Knee Replacement

Overview

As seen in the ‘basics’ section of the website the knee essentially consists of three joints. The kneecap joint (patellofemoral joint) and the joints between your thigh bone and shin bone on the inside and outside of the knee (the medial and lateral tibiofemoral joints). It makes sense therefore in certain patterns of wear that we replace only the part of the knee that is worn. Would you like to know more / click for more… The knee must meet strict criteria to qualify for this – namely the knee must have good movement, not be too bent or deformed and have intact ligaments. The medial knee compartment is replaced far more that the lateral knee compartment or knee cap joint.

The partial knee versus total knee debate

Doing a knee replacement is a compromise. It is the best solution engineers and surgeons can provide to mimic the anatomy and function of the knee. Certainly there are positives and negatives when comparing a partial knee replacement to a total knee replacement.

Positives to partial knee replacement

Smaller ‘minimally invasive’ incision, lower levels of post operative pain, lower chance of needing a blood transfusion, lower infection rate, feels more like a normal knee as ligaments are preserved, earlier recovery, more movement, can be revised relatively easily to a total knee replacement if needed.

Negatives to partial knee replacement

The rest of the knee may wear over time and thus need replacing and a partial knee replacement has higher revision rates than total knee replacements (revision rate – the rate of needing to remove the implants and replace with another total knee replacement). I think that historically the revision rates were higher because of implant design / technique / low numbers performed and certainly when people had ‘pain’ after a partial knee they were revised to a total knee quickly… sadly many of the ‘painful’ partial knees continued to have a ‘painful’ total knee replacement. Surgeons have learned that revising implants for ‘pain’ with no cause found tends to lead to more misery for the patient and the surgeon. Another reason they are revised sooner is because they are put in physiologically younger, more active patients who get on and use them!

How long will my knee replacement last?

We know from research that the younger the patient has a joint replacement the higher the chance of it needing revising.  If you have a total knee replacement under the age of 55 then you have a 12% revision rate at 10 years compared to a 2% revision rate if you are over the age of 80 (clearly very significant thus patients will need to be aware and counselled about the likelihood of needing another knee replacement in the future). Pooled national data suggests that the failure rate for a partial knee replacement is 5% at 5 year and for a total knee is 2% at 5 years.

Total Knee Replacement

This is the historical ‘gold standard’ of treatment for the knee with severe arthritis. Ideally a multitude of methods to try and control your symptoms should have been exhausted before you commit to having a total knee replacement. This is major surgery where the lining of your knee is removed and replaced with metal both on the end of your tibia and femur. In between the metal you have a plastic insert that acts like the lining of your joint. Would you like to know more / click for more…  In certain circumstances the lining of your patella may be removed and replaced with a plastic ‘button’. This is a very effective method of reducing pain from arthritic knees. The procedure will take several weeks to get over the acute surgery and you will ‘settle in’ to your new knee rapidly and continue to improve over the course of 18 months. Evidence would suggest that more than 80% of patients are happy with a knee replacement. My feeling is that in my practice and in discussion with knee colleagues that this figure is anecdotally higher.

Osteotomy

Osteotomy is the process of cutting bone and realigning the knee by pivoting on this cut area. This may be performed typically for the younger, active patient with arthritis or someone with chronic ligament damage. Scans and X-rays of the whole of your leg need to be taken to work out the way your weight goes through your knee. Using computer software we can work out how much we need to alter the shape of your bone. It involves changing the way that your weight is transmitted through your knee – essentially off-loading the painful part of your knee.  This involves a cut to your tibia and/ or femur (depending on your wear and tear pattern and severity) changing the shape of your bone and fixing it in a new place to heal with a plate and screws. A bone graft may need to be taken to fill in the gap left in the bone. The most common type of osteotomy is for people who have arthritis mainly affecting the medial part of the knee – people who notice they are becoming more ‘bow-legged’. There are strict criteria to follow to ensure a good outcome. Poor outcomes can be seen in the older, smoker with more advanced arthritis.

Arthroscopy

Before surgery

If you have medical conditions then you may be invited to attend a pre-assessment clinic by one of our specialist nurses. Routine blood tests, tracing of the chest (ECG) and an MRSA swab will be performed to ensure you are safe to be admitted to hospital.

If you have any source of infection then you will need to contact us at your earliest convenience. For example any cuts or grazes near the knee or a dental / chest infection. Your surgery may well need to be postponed for your safety and to reduce the risk of infection.

Some medication for the heart / tablets to thin the blood / tablets to control rheumatoid arthritis will need to be stopped and can be discussed with our pre-assessment team.

Seeing a physiotherapist prior to surgery will improve your recovery after surgery.

Follow instructions to stop eating and drinking before surgery. Usually 6 hours before you should not eat or drink.

We perform pre-operative checks according to the World Health Organisation to ensure that we operate on the correct site.

During Surgery

You will have a light general anaesthetic administered to you.

Two small cuts are placed either side of your knee cap tendon to allow access to the knee from the front. Occasionally more small cuts are needed to gain access to difficult areas of the knee.

Sterile fluid is allowed into your knee to give a better view.

A special camera (arthroscope) is inserted through one of the cuts and specialised equipment can be inserted into your knee under direct vision to remove or repair the painful areas of your knee.

Once finished the fluid is removed, local anaesthetic inserted and the skin closed with adhesive dressings.

After surgery

You will need to recover from the anaesthetic given and that should not take more than a few hours.

The knee may feel some discomfort but should be easily managed with painkillers such as paracetamol or ibuprofen.

You will be seen by physiotherapy staff to ensure you understand any special instructions from surgery and issue you with a brace or crutches if needed. You will also get an information sheet with activities to perform to ensure a quicker recovery to function.

If you are deemed to be at high risk of DVT then you will go home with tablets that thin the blood for 2 weeks. These sadly can increase the risk of bleeding and swelling in and around the knee.

Risks of arthroscopic surgery

An arthroscopy is generally considered to be a low-risk procedure, but like all types of surgery it does carry some. Your individual circumstances will be discussed at the time if you decide to opt for surgery.  It is normal to experience short-term problems such as swelling, bruising, stiffness and discomfort after an arthroscopy. It is common to feel discomfort at the ‘portal’ sites which can take a few months to fully settle. In some circumstances there may be a lot of non-reversible damage to your knee and thus the aim is to make your knee better, rather than normal. Thus you can have persisting discomfort despite adequate surgery.

More serious problems are much less common, occurring in less than 1 in 100 case and include:

A blood clot that develops in one of your legs – this is known as deep vein thrombosis (DVT) and it can cause pain and swelling in the affected limb. This can sometimes go to the lungs and cause a pulmonary embolus (PE) which in rare circumstances can cause death.

Infection inside the joint – this is known as septic arthritis and it can cause a high temperature (fever), pain and swelling in the joint

Bleeding inside the join – Will produce swelling and increased pain.

Accidental damage to the nerves that are near the joint – this can lead to numbness, sensitivity and some loss of sensation, which may be temporary or permanent.

Chronic regional pain syndrome – is a greater than normal reaction by the body to an injury or surgery. This can lead to chronic pain, swelling and skin changes.

Knee Replacement Surgery

Before surgery

If you have medical conditions then you may be invited to attend a pre-assessment clinic by one of our specialist nurses or if you have a complex medical history then you will be also seen by a consultant anaesthetist. Routine blood tests, tracing of the chest (ECG) and an MRSA swab will be performed to ensure you are safe to be admitted to hospital.

If you have any source of infection then you need to contact us at your earliest convenience. For example any cuts or grazes near the knee or a dental / urinary / chest infection. Your surgery may well need to be postponed for your safety. If you have had any injections into your knee performed too then we will have to postpone due to increased risk of infection.

Some medication for the heart / tablets to thin the blood / tablets to control rheumatoid arthritis will need to be stopped and can be discussed with our pre-assessment team.

Seeing a physiotherapist prior to surgery will improve your recovery after surgery.

Follow instructions to stop eating and drinking before surgery. Usually 6 hours before you should not eat or drink.

We perform pre-operative checks according to the World Health Organisation to ensure that we operate on the correct site.

During Surgery

Most people have a spinal anaesthetic where a needle is inserted into your back and you do not feel anything from the waist down. This is accompanied by medication to make you relax and you will not remember anything from the surgery if you wish. Due to medical reasons you may need a general anaesthetic or if the spinal injection does not work.

A cut is made along the front of your knee allowing a good view of the knee joint. The damaged surfaces of the bone are carefully removed and a new knee will be cemented onto the ends of your femur and tibia with a plastic liner between them. The knee cap may also be replaced with a plastic ‘button’.

To reduce swelling and improve your recovery a mixture of anti-inflammatory, local anaesthetic and drugs to reduce bleeding will be injected around your new knee. A further dose of a chemical called tranexamic acid is given to help reduce the risk of bleeding. This is part of an enhanced recovery programme.

The knee is meticulously stitched up and a layer of ‘superglue’ placed over the skin to reduce the risk of bleeding and infection.  All stitches used are dissolvable so no painful removal of stitches needed.

After surgery

You will need to recover from the anaesthetic and the feeling will gradually return to your legs. Strong painkillers are given to help reduce the discomfort.

You will be encouraged to get up and walk as soon as you feel able. This is one of the many ways we reduce the risk of clots, along with injections of medication into your tummy, stockings on your legs (if well fitting) and pumps on your feet and calf.

You will be seen by physiotherapy staff that will ensure you are safe walking with crutches or a frame. You will also get an information sheet with activities to perform to ensure a quicker recovery to function.

People should expect to go home in 2 days.

Risks of Knee Replacement Surgery

A knee replacement is a major undertaking for your body. The overall rate of complication is 1 in 20 but most are minor and can be managed successfully. The risk of death is very low and has actually halved over the past few years to a chance of 0.2% within the first 45 days of surgery (this time is the highest risk).

Infection of the wound – this may be treated with antibiotics but deeper infection will require further surgery and may need to remove the knee implants. 1-2%.

Haematoma – swelling in the knee cased by bleeding.

Ligament, artery or nerve damage – rare.

DVT or PE (Blood clots) – They can happen in anyone who has had surgery to their legs and are relatively immobile. The risk is reduced by medication taken to thin the blood up to 14 days after surgery.

Arthrofibrosis – A build up of scar tissue in certain individuals after major surgery. There may be overlap with chronic regional pain syndrome.

Numbness – It is common to have numbness on the outer side of your knee scar.

Fracture – can occur when dealing with patients with soft bone or after replacing the knee cap.