Total knee replacement

Introduction

A Total Knee Replacement (TKR) or Total Knee Arthroplasty is an operation that replaces an arthritic knee joint with artificial metal and plastic replacement parts called implants/prostheses.

The procedure is usually recommended for older patients who are suffering from pain and loss of function due to arthritis and whose symptoms cannot be controlled with non-surgical/conservative methods of therapy.

The typical knee replacement resurfaces the ends of the femur (thigh bone) and tibia (shin bone) with metallic components with a polyethylene liner inserted between them and resurfacing of the patella (knee cap) when indicated.

Arthritis

Causes include

  • Primary osteoarthritis

  • Trauma (fracture)

  • Increased force e.g., being overweight, etc.

  • Infection

  • Bleeding disorders

  • Connective tissue disorders

  • Inflammation e.g., Rheumatoid arthritis

In an Arthritic Knee

  • The cartilage lining is thinner than normal or completely absent. The degree of cartilage damage and inflammation varies with the type and stage of arthritis

  • The capsule and joint lining of the arthritic knee may become swollen

  • The joint space is narrowed and irregular in outline; this can be seen in an X-ray image

  • Bone spurs or excessive bone (called osteophyte) can also build up around the edges of the joint

The combinations of these factors make the arthritic knee stiff and can limit activity due to pain and/or fatigue

Diagnosis

The diagnosis of osteoarthritis is made on history, physical examination & X-rays.

There is no blood test to diagnose Osteoarthritis (wear & tear arthritis).

Benefits

The decision to proceed with TKR surgery is a cooperative one between you, Mr Frame, your family and your general practitioner.

The benefits following surgery are relief of painful symptoms of arthritis. These include

  • Severe pain that limits your everyday activities including walking, shopping, visiting friends, getting in and out of chair, gardening, etc.

  • Pain waking you at night

  • Deformity- either bowleg or knock knees

  • Stiffness can sometimes be improved

Prior to surgery you should have tried some conservative treatments such as simple analgesics, weight loss, anti-inflammatory medications, modification of your activities, walking sticks, muscle strengthening exercise and physiotherapy.

Pre-Operation

  • Mr Frame will send you for routine blood tests and any other investigations required prior to your surgery

  • You will be asked to undertake a general medical check-up at pre-assesment.

  • You should have any other medical, surgical or dental problems attended to prior to your surgery

  • Make arrangements for help around the house after surgery

  • Cease any naturopathic or herbal medications 10 days before surgery

  • Stop smoking as long as possible prior to surgery

Day of your surgery

  • You will be admitted to the hospital, usually on the day of your surgery

  • Further tests may be required on admission

  • You will meet the nurses and answer some questions for the hospital records

  • You will meet your Anaesthetist Dr Sparkes, who will ask you a few questions

  • You will be given hospital clothes to change into

  • Just prior to surgery you will be transferred to the operating theatre

  • The surgical area will be shaved and cleaned prior to your surgery. A tourniquet will be placed around your thigh during the surgery

Surgical Procedure

Each knee is individual and knee replacements take this into account by having different size options available for your knee. If there is more than the usual amount of bone loss, sometimes extra pieces of metal or bone are added.

Surgery is performed under sterile conditions in the operating room under spinal or general anaesthesia. You will be on your back and the tourniquet applied to your upper thigh helps to reduce blood loss. Surgery takes less than an hour. 

The surgeon exposes the bones of the knee joint.

The damaged portions of the femur and tibia are then cut at the appropriate angles using specialized jigs. Trial components are then inserted to check the accuracy of these cuts and determine the thickness of plastic required between these two components. The patella (kneecap) may be replaced depending on a number of factors and depending on the surgeon’s judgement during surgery.

The real components are then implanted using bone cement and the knee is again checked to make sure that the implants are stable, well balanced and that the knee joint moves smoothly. The knee is then carefully closed with clips and the knee dressed and bandaged.

 

Post-Operation Course

When you wake, you will be in the recovery room with intravenous drips in your arm, potentially a tube (catheter) in your bladder and a number of other monitors to check your vital observations. You may have a button to press for pain medication through a machine called a PCA machine (Patient Controlled Analgesia).

Once stable, you will be taken to the ward. The post-op protocol is for you to sit out of bed and start moving your knee and walking, sometimes, even on the day of surgery. The bandaging will be removed usually on the 1st post op day to make movement easier. Your rehabilitation and mobilisation will be supervised by a physiotherapist.

To avoid lung congestion, it is important to breathe deeply and cough up any phlegm you may have.

Your surgeon will use one or more measures to minimize blood clots in your legs, such as inflatable leg coverings, stockings and tablets to thin the blood to avoid clots or DVT’s, which will be discussed in detail in the complications section.

Usually, you will remain in the hospital for 2-3 days then you will return home. You will need physiotherapy following surgery. Regular exercises should include pushing the knee straight using your thigh muscles, trying to lift the leg straight up off the bed and working at exercises to increase the bend in the knee.

You will be discharged with a zimmer or crutches and usually progress off them by six weeks. 

The knee will be swollen and ice, compression and cold will help with the pain and discomfort. A special cool compression device is a great way of helping to speed up your recovery. Click here to take a look at the AIRCAST CryoCuff we can supply from 'The Kit Room'.

Your clips are removed at approximately 10 days.

Bending your knee is variable, but by 6 weeks should bend to 90 degrees. The goal is to obtain up to 120 degrees of flexion.

Once the wound has healed, you may shower. A waterproof covering is available to buy before your surgery to make life easier and keep the wound dry and allow you to shower earlier. Click here to take a look in ‘The Kit Room’.  You can drive at about 6 weeks, once you have regained control of your leg. You must be able to perform an emergency stop without pain before you are safe to drive. You should be walking reasonably comfortably by 6 weeks.

More physical activities, such as sports previously discussed, may take 3 months to do comfortably.

When you go home you need to take special precautions around the house to make sure it is safe. You may need rails in your bathroom or to modify your sleeping arrangements, especially if they are up a lot of stairs.

You will usually have a 6 week check up with Mr Frame who will assess your progress.

You are always at risk of infections especially with any dental work or other surgical procedures where germs (bacteria) can get into the blood stream and find their way to your knee. Always tell the dentist or surgeon that you have a total knee replacement.

If you ever have any unexplained pain, swelling or redness or if you feel generally unwell, you should see your general practitioner as soon as possible or contact us on info@wessex-knee.com

 

Risks and Complications

 

  • As with any major surgery, there are potential risks involved. The decision to proceed with the surgery is made because the advantages of surgery outweigh the potential disadvantages

  • It is important that you understand the risks before the surgery takes place

 

Complications can be medical (general) or local complications specific to the knee

Medical complications include those of the anaesthetic and your general well-being. Almost any medical condition can occur, so this list is not exhaustive. Complications include:

 

  • Allergic reactions to medications

  • Blood loss requiring transfusion with its low risk of disease transmission

  • Heart attacks, strokes, kidney failure, pneumonia, bladder infections Complications from nerve blocks such as infection or nerve damage Serious medical problems can lead to ongoing health concerns, prolonged hospitalization or rarely death. Your surgeon will do everything possible to minimise the risks

 

Local Complications

 

Infection

Infection can occur with any operation. In the knee this can be superficial or deep. Infection rates vary. If it occurs, it can be treated with antibiotics but may require further surgery. Very rarely your new knee may need to be removed to eradicate infection. Antibiotics will be given during your knee replacement to help avoid this.

 

Blood Clots (Deep Venous Thrombosis)

These can form in the calf/thigh muscle veins and can travel to the lung (Pulmonary embolism). Injections and tablets can be used to try and reduce the risk of clots. These clots can occasionally be serious and even life threatening. If you get calf pain or shortness of breath at any stage, you should notify your doctor, contact 111 or if an emergency 999.

 

Stiffness in the Knee

Ideally your knee should bend beyond 100 degrees but on occasion, the knee may not bend as well as expected. Sometimes manipulations are required. This means going to the operating theatre where the knee is bent for you under anaesthetic.

 

Wear

The plastic liner eventually wears out over time and may need to be replaced.

 

Wound Irritation or Breakdown

The operation will always cut some skin nerves, so you will inevitably have some numbness around the wound. This does not affect the function of your joint. You can also get some aching around the scar. Vitamin E cream and deep tissue massage can help reduce this.

Occasionally, you can get reactions to the sutures or a wound breakdown that may require antibiotics or rarely, further surgery.

 

Cosmetic Appearance

The knee may look different than pre-operatively because the alignment is corrected to allow proper function.

Leg length inequality

This is also due to the fact that a corrected knee is straighter and is unavoidable.

 

Dislocation

An extremely rare condition where the ends of the knee joint lose contact with each other or the plastic insert can lose contact with the tibia (shinbone) or the femur (thigh bone).

 

Patella problems

The patella (kneecap) can dislocate. This means it moves out of place and it can break or loosen.

 

Ligament injuries

There are a number of ligaments surrounding the knee. These ligaments can be torn during surgery or break or stretch out any time afterwards. Surgery may be required to correct this problem.

 

Damage to Nerves and Blood Vessels

Rarely nerves and blood vessels can be damaged at the time of surgery. Damaged structures will be repaired, but a second operation may be required. Nerve damage can cause a loss of feeling or movement below the knee and can be permanent.

Fractures or breaks in the bone can occur during surgery or afterwards if you fall. To repair these, you may require surgery.

Discuss any concerns thoroughly with your Mr Frame.

 

Summary

Surgery is not a pleasant prospect for anyone, but for some people with arthritis, it could mean the difference between leading a normal life or putting up with a debilitating condition. Surgery can be regarded as part of your treatment plan—it may help to restore function to your damaged joints as well as relieve pain.

TKR is one of the most successful operations available today. It is an excellent procedure to improve your quality of life, take away pain and improve function. 8/10 have resolution of their arthritis pain, 1/10 have some pain but improved significantly, 1/10 can have ongoing pain or pain that is worse than before surgery. In general, 90-95% of knee replacements survive 15 years, depending on age and activity level.

Surgery is only offered when non-operative treatment has failed. It is an important decision to make and ultimately it is an informed decision between you, Mr Frame, your family and general practitioner.

Although most people are extremely happy with their new knee, complications can occur, and some may experience dissatisfaction with the outcome so patients must be aware of this prior to making a decision. If you are undecided, it is best to wait until you are sure that this is the procedure for you.

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