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Total Knee Replacement (Knee Arthroplasty)

• Introduction
• Arthritis
• Benefits
• Pre-op
• Day of your surgery
• Surgical procedure
• Post-operation course
• Risks and complications
• Summary

Introduction

A total knee replacement (TKR) or total knee arthroplasty is a surgery
that replaces an arthritic knee joint with an artificial metal or plastic replacement parts called the ‘prostheses'.

The procedure is usually recommended for older patients who suffer
from pain and loss of function from arthritis and have failed other
conservative methods of therapy.

The typical knee replacement, replaces the ends of the femur (thigh bone)
and tibia (shin bone) with plastic inserted between them and usually the patella (knee cap)

Arthritis

Arthritis is a general term covering numerous conditions where the
joint surface (cartilage) wears out. The joint surface is covered by a
smooth articular surface that allows pain free movement in the joint.

When the articular cartilage wears out, the bone ends rub on one another
and cause pain. There are numerous conditions that can cause arthritis
and often the exact cause is never known. In general, but not always it
affects people as they get older (Osteoarthritis) .

Other causes include

• Trauma (fracture)
• Increased stress e.g., overuse, overweight, etc.
• Infection
• Connective tissue disorders
• Inactive lifestyle- e.g., Obesity, as additional weight puts extra force
  through your joints which can lead to arthritis over a period of time.
• 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 of the arthritic knee is swollen
• The joint space is narrowed and irregular in outline; this can be
  seen in an X-ray image.
• Bone spurs or excessive bone can also build up around the edges
  of the joint.

The combinations of these factors make the arthritic knee stiff and limit activities due to pain 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 co-operative one between
you, your surgeon, family and your local doctor.

The benefits following surgery are relief of 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 knee
• Stiffness

Once these have failed it is time to consider surgery. Most patients who
have TKR are between 60 to 80 years, but each patient is assessed
individually and patients as young as 20 or old as 90 are occasionally
operated on with good results.

Pre-operation

- Your surgeon will send you for routine blood tests and any other
investigations required prior to your surgery

- You will asked to undertake a general medical check-up with a physician

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

- Make arrangements around the house prior to surgery

- Cease aspirin or anti-inflammatory medications 10 days prior to surgery
as they can cause bleeding.

- 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 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, who will ask you a few questions.

- You will be given hospital clothes to change into and have a shower
prior to surgery.

- The operation site will be shaved and cleaned.

- Approximately 30 mins prior to surgery, you will be transferred to the operating theatre.

Surgical procedure

Each knee is individual and knee replacements take this into account by
having different sizes for you 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 theatre
under spinal or general anaesthesia. You will be on you back and a
tourniquet applied to your upper thigh to reduce blood loss. Surgery takes about two hours .

The surgeon cuts down to the bone to expose 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 to place in between these two components. The patella (knee cap) may be replaced depending on a number of factors depending
on surgeon's choice.

The real components are then inserted with or without cement and the
knee is again checked to make sure things are working properly. The knee
is then carefully closed and drains usually inserted, and the knee
dressed and bandaged.

Post operative

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

Once stable, you will be taken to the ward. The post-op protocol is
surgeon dependant, but in general your drain will come out at 24 hours
and you will sit out of bed and start moving you knee and walking on it
within a day or two of surgery. The dressing will be reduced usually on
the 2nd post of day to make movement easier. Your rehabilitation and mobilization 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 orthopaedic surgeon will use one or more measures to minimize
blood clots in your legs, such as inflatable leg coverings, stockings and injections into your abdomen to thin the blood clots or DVT's, which
will be discussed in detail in the complications section.

A lot of the long term results of knee replacements depend on how much
work you put into it following your operation.

Usually you will be in hospital for 5-7 days and then either go home or to
a rehabilitation facility depending on your needs. You will need physiotherapy on your knee following surgery.

You will be discharged on a walking aid either on frame or crutches and
usually progress to a walking stick at six weeks.

Your sutures are sometimes dissolvable but if not are removed at approx
10 days.

Bending you knee is variable, but by 6 weeks should be to 90 degrees.
The aim is to get 110-115 degrees of movement.

Once the wound is healed, you can take a shower. You can drive at about
6 weeks, once you have regained control of your leg. You should be
walking reasonably comfortably by 6 weeks.

More physical activities, such as sports previously discussed may take
3 months to be able 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 weeks check up with your surgeon who will
assess your progress. You should continue to see your surgeon for the
rest of your life to check your knee and take X-rays. This is important as sometimes your knee can feel excellent but there can be a problem only
recognized on X-ray.

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.

If you ever have any unexplained pain, swelling, redness or if you feel unwell you should see your doctor as
soon as possible.

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 are informed of these 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
complete.

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.

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.

Blood clots (Deep Venous Thrombosis)
These can form in the calf muscles and can travel to the lung
(Pulmonary embolism). These 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.

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 theatre and under anaesthetic the
knee is bent for you.

Wear- the plastic liner eventually wears out over time, usually 10 to
15 years and may need to be changed.

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 massaging can help reduce this.

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

Cosmetic Appearance –
The knee may look different than it was because it is put into the correct
alignment to allow proper function.

Leg length inequality-
This is also due to the fact that a corrected knee is more straight and
is unavoidable.

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

Patella problems
Patella (knee cap) can dislocate that is, 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 these can be damaged at the time of surgery. If recognized they
are 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 fix these, you may require surgery.

Discuss your concerns thoroughly with your orthopaedic surgeon prior to surgery.

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 peoples quality of life, taking away pain
and improving function. In general 90-95% of knees survive 15 years
depending of age and activity level.

Surgery is only offered once non-operative treatment has failed. It is an
important decision to make and ultimately it is an informed decision
between you, your surgeon, family and medical practitioner.

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