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What is a total knee replacement?

A total knee replacement is the name given to surgery that involves replacing your knee joint because it has been worn or damaged by arthritis.

Arthritis is a condition that affects the cartilage lining of a joint, wearing it away and leaving the bone exposed. This causes pain, stiffness and instability.

During surgery, the surgeon removes the damaged portions of your thigh bone (femur) and shin bone (tibia), then covers them with metal implants that are fixed in place using a specialized bone cement. A tough plastic spacer is inserted between these metal parts to serve as your new joint cartilage, helping your knee move smoothly. If needed, the underside of your kneecap (patella) is also resurfaced with a plastic cap, or “button,” to enhance comfort and overall knee function. 

What are the alternatives?

Unfortunately arthritis cannot be cured. Although there are ways to control the symptoms of arthritis, they may only provide temporary relief of your pain.

Alternatives to surgery are:

  • Losing weight – this will reduce the load on your knee.
  • Steroid injections can help relieve pain and inflammation. Depending on the condition of the knee, the benefits can last from a few days to more than 6 months.
  • Taking pain killing medications such as paracetamol. This can help reduce the inflammation and pain in your knee. Anti-inflammatories such as ibuprofen are also very effective but please check with your GP before taking as they can have damaging side-effects.
  • Use of walking aids.
  • Gentle exercises and physiotherapy.
  • Use of a knee brace and shoe inserts.

What are the risks and possible complications?

Common (2-5%)

  • Ongoing pain post surgery: There are a small group of patients who can experience this. Some patients also experience a “clunking” sensation in their knee, this can be normal. Up to 15% of patients may feel some on-going problems with the new knee.
  • Post-op blood clots (DVT): This risk is reduced as much as possible by early mobilisation, compression device pumps, exercises and medication to thin the blood. This medication is taken for 14 days following your surgery.
  • Loosening: The artificial joint may, in the long-term, work loose in the bone and may require revision. Approximately 85% of knee replacements that are not infected will last 20 years or more.
  • Bleeding: This is usually small. It is rare to require a blood transfusion. The current transfusion rate in our unit is <1%.
  • Knee stiffness: This may occur after the operation. Manipulation of the joint (under general anaesthetic) may be necessary in up to 5% of cases. This usually requires another anaesthetic and a separate trip to hospital.

Less common (1-2%)

  • Infection: Infection around a new joint is a serious complication. It is therefore important that you do not have any infections prior to surgery, for example; skin, chest or urinary tract infections. Should you have an infection prior to your surgery, please inform the pre-assessment staff.

Rare(less than 1%)

  • Nerve/blood vessel injury: Whilst rare, injury to the nerves or blood vessels around the knee can occur during surgery.
  • Fracture: This can happen in the bone around the artificial joint during or after surgery – treatment will depend on the location and extent of the fracture.
  • Wound healing problems: The scar can become keloid. This means it can be sore, red and thickened. This can especially happen in Afro-Caribbean people. Massaging of the scar once healed can help. You will be advised regarding this. It can also be normal to have an area of numbness. This is because the nerves supplying the area are cut whilst making the incision.
  • Pulmonary Embolism (PE): This is a consequence of a DVT. The clot can spread to the lungs which makes breathing very difficult. A PE can be fatal.
  • Altered leg length: The leg that has been operated on may appear longer or shorter.
  • Joint dislocation: If this does occur, the joint normally can be put back into place without the need for surgery. If this is not possible, surgery may be required.
  • Death: This risk of death according to the 2015 National Joint Registry report is 0.33% in 90 days following surgery. This is usually due to heart attack, stroke or PE. The risk is higher in patients who are obese or who smoke. 

What happens before your admission to hospital?

You will be seen in the pre operative assessment clinic prior to your operation. This is to assess your fitness for surgery. You will be given information regarding your surgery and you will be able to ask questions.

You will also be contacted by the Therapy Team prior to admission. They will assess your social circumstances, discuss your home environment and help you plan your discharge home hospital. This helps to pre-empt any problems prior to your surgery and facilitate your discharge after your operation.

Time spent in hospital following surgery has reduced significantly over the last few years. Changes in surgery technique and support allows patient to go home within 24 hours of their surgery. There are many advantages to being in your own environment, reducing the risk of complications and being in control of your own recovery.

Although most patients will go home within 24 hours, this is not suitable for every patient having a knee replacement. You must be medically fit and well, have friends and family to support you, have transport to and from the hospital and have the motivation to succeed. The team will speak to you on an individual basis. 

The surgery is done under a spinal anaesthetic. This involves an injection into your lower back to numb the lower half of your body. You may be awake or have mild sedation during the operation. You can bring some headphones and listen to your favourite music/podcast. There will be a large screen so you will not be able to see the surgery. The spinal anaesthetic wears off quickly and allows you to recover and walk sooner after your operation. Your anaesthetist will explain more about the anaesthetic on the day of your surgery. 

Pain Relief

It is normal for your knee to be painful after surgery.  You will be given medication to control pain and reduce nausea/vomiting. You will have access to strong pain relief medication which is started before your surgery. It is important that you take your pain relief regularly and speak to the nursing team if you are in a lot of pain. 

What happens when I go home?

You will be contacted by the Arthroplasty Nurse or a member of the ward team the day after your discharge to see how you are managing at home.

You will also be given the ward telephone numbers to contact 24/7 should you have any questions or concerns.

Your wound will be covered with a waterproof dressing and should not be changed or disturbed until your clips/stitches are removed by your GP practice nurse at two weeks . It is normal to see blood stained fluid on the dressing. 

If the fluid leaks outside of the dressing or you have any concerns about the wound, please contact the ward for advice.

You will be referred to outpatient Physiotherapy on discharge. Your Physiotherapy will start approximately two weeks post-operatively. This will be a face to face appointment. The therapy team on the ward will discuss this appointment with you before you are discharged.

You will be reviewed by your surgeon 3-6 months after your surgery.

Coming in to hospital

You will be admitted to hospital on the day of your surgery. Admissions times vary but are typically 7am or 12pm. You will not be allowed to eat anything for 6 hours prior to your surgery. You can drink tea/coffee with a small amount of milk up to 2 hours before your surgery. Clear fluid (water/black tea/coffee) is allowed until you are called to theatre. You may also receive a carbohydrate drink 2 hours prior to your surgery.

You will be discharged from the hospital within 24 hours of your surgery. Please plan for someone to bring you into hospital and take you home on your discharge. 

After your operation

The operation takes approximately one and a half hours, which includes anaesthetic time. You will wake up in the recovery room of the theatre, where you will remain until you are awake. It is very important that you alert the nurse if you are experiencing pain. 

Getting moving after the operation
You will be assessed by the Therapy team when you return to the ward. Early mobilisation is actively encouraged. The therapy team will teach you:

  • Exercises to increase the range of movement and muscle control of your knee.
  • How to get in and out of bed.
  • How to walk with elbow crutches
  • How to climb stairs.

A check X-ray of your new knee will be taken prior to your discharge.

Once you have been discharged from the ward you can gradually increase your activity levels as pain allows. You can go for a walk outside but it is advisable to go with someone the first time and always make sure that you are able to get back again. You will have outpatient physiotherapy following your discharge which will be arranged before you go home. You can increase the repetitions of each exercise as they become easy, e.g., from x10 up to x15 and then up to x20. You should continue your exercises for 6-12 weeks. 

Occupational Therapy

It is essential to take time now to organise yourself at home so you will be able to manage safely and independently once you return home. Please read and act upon the recommendations and advice listed below prior to your hospital admission.

Things to avoid for 6 – 8 weeks following surgery

  • You may find it difficult to kneel on your operated knee.
  • You should avoid jarring or twisting movements, such as digging in the garden, jumping, running, pushing a vacuum cleaner, shopping trolley or lawn mower. 

Chairs

  • Ideally your chair should have a firm seat, supportive back and arms to push up on.
  • If your chair is low, you should make alternative arrangements. For example, you could raise your chair with an extra cushion or folded blanket under the existing cushion. Alternatively, borrow higher furniture prior to admission.

Beds

  • Ideally your bed should have a well sprung mattress and should not be too low.

Toilet

  • You will be advised whether or not you will require toilet equipment. If required these are loaned to you by the hospital.

Bathing/showering

  • We do advise you not to soak in a bath for the first 6 weeks following your surgery.
  • When you first return home, we advise you to have a strip wash at a basin rather than getting into a bath or shower. You may want to consider having somewhere to sit while you wash; this could either be sitting on the toilet seat or using a suitable high stool/chair.
  • You may use a shower within a cubicle when you are confident you can step into the shower safely and do not need a mobility aid to maintain your standing balance. We advise you to have someone with you the first time you access your shower. Always use a nonslip mat and your wound should be covered by a waterproof dressing.

Dressing

  • You must bring clothes that are loose fitting to wear in hospital. These are easier to get on and off; and it will also promote a sense of normality and be more comfortable when doing your rehabilitation. Please bring in flat non-slip footwear.
  • When getting dressed, sit on a chair or bed. You will find it easier to dress the operated leg first and to undress it last
  • You may need to purchase a long handled shoe horn, a helping hand and equipment to assist you.

Kitchen

  • Move essential items around the home to a height you can reach comfortably. You must not bend down to reach items from low level cupboards or drawers.
  • Place the things you use most often (e.g., tea/coffee, mugs and kettle) together in one place on the kitchen worktop to reduce the need to move around the kitchen unnecessarily.
  • Plan to have easy to prepare meals in the first few weeks after your surgery; this may include tinned items or frozen meals. Keep essential food items in easy to reach places, e.g., milk at waist height in the fridge.
  • Initially after discharge, you will not be able to carry items around the home if you are using a walking aid. You may need to consider sitting in the kitchen to have meals/drinks, or a bag carried across your body to transport items to the lounge/dining room in sealed containers. 
  • Ask relatives or friends to help with heavier domestic tasks, i.e. laundry, vacuuming, making beds, housework and shopping, for the first few weeks after your operation. 
  • Remove all loose-edged mats to prevent tripping. 

Animals

If you own pets, consider the needs of your animals prior to admission and make any necessary arrangements for their care. Please note you may find it extremely uncomfortable in the first few weeks to bend down to the floor to tend to your pet.

Getting in and out of a car

  • You should sit in the front passenger seat, never the back seat.
  • Have the passenger seat moved back as far on its runners as it will go in order to maximise the leg room. 
  • Sit as far back onto the seat of the car as possible, remembering to keep your operated leg straight out in front of you.
  • You should not drive for 6 to 8 weeks following your surgery. You will be advised when you can start driving at your follow up appointment.

Please prepare your home and support for your discharge from hospital. You must have someone to bring you into hospital and take you home.

Occupational Therapists do not routinely see you on the ward unless you have a functional need for discharge.

Where to get help/advice on discharge

  • Before discharge home you will be given a contact number to ring should you have any concerns, questions or problems regarding your new knee joint. 
  • If you have concerns regarding your wound, please contact the Arthroplasty Nurse at Heatherwood/the ward you had your surgery.
  • It is not uncommon to experience pain for many weeks following your surgery. You will be discharged home with 7 days supply of pain relief medication, but please be aware that you may require a further prescription from your GP.
  • We advise that you do not go on a long haul flight for 12 weeks short haul flight for 6 weeks following your operation. This is due to the increased risk of Deep Vein Thrombosis.
  • Post operative knee swelling and bruising is common following total knee replacement. You will be advised about ice therapy which will help alleviate this. If, however, you experience pain in your calf or thigh, you must seek medical advice.

What to bring into hospital with you

  • Walking aids.
  • Slippers or trainers – please, no mules or other backless footwear. Please note your feet and ankles may swell following surgery so your regular footwear may not fit.
  • Loose fitting daytime clothing.
  • Loose fitting nightwear and dressing gown.
  • Personal toiletries.
  • Long handled aids – shoehorn, Helping hand, clearly labelled with your name.
  • Current medication in labelled boxes.
  • Any splints/braces you usually wear.
  • Glasses, hearing aid, dentures, etc., you usually wear.
  • Money in small amounts for Patientline telephone and television – Frimley Park only.

Please do not bring valuables into the hospital.

Useful Contacts

Heatherwood Hospital:

Frimley Park Hospital:

Wexham Park Hospital:

Contact us

If you have any queries relating to this information, please contact the Orthopaedics service.

About this information

Service:
Orthopaedics

Reference:
N/010

Approval date:
24 June 2025

Review date:
24 June 2028

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Important note 

This page provides general information only. It is developed by clinical staff and is reviewed regularly every 3 years for accuracy. For personal advice about your health, or if you have any concerns, please speak to your doctor.