Preparing for knee replacement

Advice to patients who are soon to have a knee replacement.

First published in 2009, and reviewed August 2023 by Dr Sheila Strover (Clinical Editor)

 

Having a knee replacement can be an anxious time, and patients should optimise both their work and their home situations before entering hospital.

Paying attention to these matters early will allow plenty of time and the minimum of rush.

 

Work preparations

It is wise to have a detailed chat with your superior about your diagnosis, treatment recommendation if it is a knee replacement and the timing when this can be done. If your job involves physical activity you may need to be away from work for up to three months. If you do a desk-type job, you may resume work as early as 2-3 weeks. This decision should be carefully considered in consultation with your surgeon as every knee, patient and activities are different.

It is wise to express a wish to be deputised to do light work when you resume work if that is possible. If you plan to return to work within six weeks it will be wise to go on to light duties for about six weeks to three months if possible. This will give you more time to recover, continue with your physiotherapy and not tax your knee more than it should be. If you job does involve heavy activities it is wise to have a discussion with your surgeon so that you follow his/her recommended guidelines.

 

Domestic circumstances

You would need to have a chat with your family regards to the decision about knee replacements. This would be in keeping with the timing and fitting in with your family. Your next-of-kin/family may need to take leave in order to support you. If you do have stairs at home it may be wise to bring your bed downstairs for a period of a week to two weeks after leaving the hospital. If you do not have anybody to look after you after surgery you should discuss a place to go to following your total knee replacement to recuperate before going home. This may be in the form of a rehabilitation place/nursing home. It is much wiser to have this chat pre-operatively than to find yourself in a bad situation after surgery. Plan any holidays well in advance. I recommend that a patient should not fly long haul flights (more than two hours either way) six weeks prior and three months after total knee replacement. This is particularly so that the deep vein thrombosis risk is kept to a minimum. You should express a desire to make your name available for cancellations if you can make it at short notice.

Driving would be allowed by most surgeons after six weeks if all is well and your ability and confidence allows you to.

Crutches can be discarded any time between two to six weeks based on the type of knee and the way your knee is going.

 

Physical preparation

A strong and supple knee is far better than a weak and stiff knee before total knee replacement. Your surgeon may refer you to a physiotherapist to improve your mobility and increase your muscle strength. This would help you to mobilise well and to keep your knee flexible after a knee replacement.

 

Pre-operative assessment

It is quite wise to have your total knee replacement when it is safe to do so. You will have a detailed pre-operative assessment four to six weeks prior to your scheduled operation. A nurse will carry out this assessment and may refer you to the anaesthetist or physician/cardiologist for further opinion if required. You will need blood tests - haemoglobin, full blood count, urea and electrolytes (you may need further tests/X-rays according to individual requirements). Most hospitals now do a routine MRSA swab - this is to pick patients who are carrying this bug. This can be eradicated prior to operation reducing risk of post-knee replacement infection. Once all your blood tests are back and if you are fit to proceed with your knee replacement a date would be offered to continue with surgery.

 

Learning about risks

Knee replacement is one of the most successful and rewarding operations. It is very helpful to relieve pain, improve your mobility and your quality of life. There are certain risks that you need to understand -

• Infection - this is thankfully a rare risk after a total knee replacement. An acceptable risk is anything less than three percent, that is if your surgeon performs a hundred knee replacements 1-3 may get infected. Infection could be just underneath your skin or involve the prosthesis. If you were to have infection after your knee replacement it is very important to seek advice from your surgeon. Most of the surgeons would only commence patients on antibiotics after making a firm diagnosis of infection and possibily determining the bug causing the infection. Antibiotics started without this diagnosis can complicate the treatment. Even if the infection appears minor you would be started on antibiotics. This may be orally or you may need to come into the hospital for intravenous antibiotics. If the infection does not come under control with mere antibiotics you may need to go back to the operating theatre for exploration/washouts. These procedures can be undertaken up to about three times to control your infection. If infection remains uncontrolled, on occasion you may need to have your prosthesis removed and antibiotic 'spacers' inserted to control infection. You may need to remain on antibiotics for a period of six to eight weeks following which - only if the infection is under control - your surgeon would embark on re-doing the knee replacement. Infection is a difficult complication for both the surgeon and patient. It is hence a widely-accepted rule to avoid high risk conditions that might increase the risk of infection. The risk of infection in diabetics and psoriatic arthritis sufferers is much higher and can amount to about 5-7 percent. (5-7 in a hundred). It is hence important to have your diabetes completely under control. Psoriatic lesions should have healed before proceeding with total knee replacement.
• Deep vein thrombosis - This is a relatively common complication following any lower limb surgery. If you do have a history of deep vein thrombosis or have anybody in the family who has had this complication, you should discuss this with your surgeon and your pre-operative assessment nurse. Deep vein thrombosis causes pain and swelling in your leg but the more dangerous complication is the clot was to get dislodged from the leg and go to the lungs - called 'pulmonary embolism'. This condition can at times be fatal. Your surgeon would take deep vein thrombosis quite seriously. The prophylactic measure to avoid deep vein thrombosis include blood thinning injections during and after surgery. You may have foot pumps and need to wear TED stockings for a period of time based on your surgeon's preference and experience. You need to remain well hydrated and stay active with frequent foot and ankle pump exercises to empty the calf blood. This risk remains from the day of surgery until about three months following your operation. A ddep vein thrombosis occurs if the blood stays stagnated in the veins in your leg. This happens if you were very immobile after operation. There are certain patients who are at a higher risk than others. A discussion with you postoperative nurse would be able to address this issue. If at any stage after operation if one was to find problems breathing or pain in the chest urgent attention should be sought. A visit to your surgeon or A&E is absolutely mandatory.
• Stiffness - Movements following total knee replacement entirely depend on the movement you had in your knee before. Your knee should be able to be straightened completely (into extension) and bend to an appropriate degree backward (into flexion). A number of knees may not be able to completely straighten before total knee replacement - this depends upon the severity of arthritis. Your surgeon may refer you to the physiotherapy department to try and soften this stiffness. It is very important to continue with extension exercises after knee replacement as it is very easy for your surgeon to bring the knee into full extension but if you do not maintain it with regular stretching exercises you will soon find your knee bended to the degree that you had before the knee replacement. It is very difficult to correct this contracture 4-6 weeks after your knee replacement.
• Flexion - Most knee replacements will bend to about 120 degrees. In the Caucasion population flexion beyond 120 degrees is not required for activities of daily living. There are some newer knee replacements that bend more than 120 degrees - however in my practice I have not seen a huge need for this. This would be required in the Asian culture and hence you should discuss this issue with your surgeon if this is required after total knee replacement. Mosst of the total knee replacement patients will achieve a bend of at least 90 degrees before they go home. This is a milestone that should be achieved as early as two weeks. Once achieved, time should be spent in maintaining it and hence regular bending and straightening exercises should be carried out at the prescription of your physiotherapist. It is quite easy to lose the bend or the ability to straighten if regular exercises are not done. If you start with a very stiff knee you will indeed need to work harder. In these situations it is not uncommon for the knee to remain stiff at discharge, two weeks or even 6-8 weeks after total knee replacement. If your knee was to remain stiff at 6 weeks following total knee replacement, your surgeon may consider aggressive physiotherapy and/or manipulation under anaesthesia. Manipulation under anaesthesia is a procedure where your surgeon would gently bend your knee while you were asleep. This is done to stretch the adhesions that have formed inside your knee and around the total knee replacement. In my experience it is very difficult to achieve correction of your knee coming out to full straightening and bending is quite easily achievable. It is again quite important to maintain the bend as it is not uncommon to have your knee re-stiffen if regular physiotherapy is not carried out.

 

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