total knee replacementOne of the most painful procedures that patients dread is a knee replacement surgery. Dr Smarajit Chakrabarty, a renowned orthopaedic surgeon practising in New Delhi answers some frequently asked questions about the procedure:

Who needs a Total Knee Replacement (TKR)?

Osteoarthritis can progress to such a stage when the pain becomes too much to bear and the patient may have difficulty walking or performing everyday activities such as climbing up a flight of stairs. On x-ray examination, the knee joint on x-ray shows sufficient damage to the cartilage lining, it may be time to consider knee replacement surgery. Doctors generally try to delay total knee replacement for as long as possible in favour of less invasive methods of treatment. However for patients with advanced joint disease, the procedure offers the best chance of relief from pain and a return to normal activity.

How is the knee ‘replaced’?

Before reading about the procedure, one needs to understand the structure of the knee joint. The knee joint is one of the largest and most complex joints of the body. It joins the thigh bone to the shin bone, and is a hinge joint. The three bones forming the knee joint are all covered with cartilage. When this cartilage is worn away, it results in arthritis.

The word ‘knee replacement’ is actually a misnomer. The knee is not ‘replaced’ as such. The parts of the bones that rub together are resurfaced with metal implants and a plastic insert is placed in between. This is usually done by a surgeon using precision instruments. First, the surgeon removes the damaged and degenerated surfaces, the cartilage lining of the thigh and shin bones (called the Femur and the Tibia respectively), and if required, also of the knee cap (the Patella). The new, metallic surfaces will then be fixed into place with cement. This creates a new, smooth cushion and a functioning joint that does not pain.

How successful is the Total knee replacement surgery?

Over 90% of people who have had Total Knee Replacement experience an improvement in knee pain and function. The success rate depends largely upon the competence of the surgeon and the quality of other facilities. It has now become a routine operation performed on over 600,000 people worldwide each year.

What are the major risks involved with the surgery?

Most surgeries go well without any complications. However, there is a small risk of infection and blood clots being formed. These can be prevented by preparing the operation theatres better and by administering antibiotics and blood thinners to the patients.

How long does the patient need to stay in the hospital?

The patient is typically admitted to hospital a day before the operation when pre-operative tests are carried out. He/she is asked to consult an anaesthetist, a physician and by a cardiologist (if required) and their clearances are obtained before the patient is operated upon. Post-surgery, the patient is discharged in about five days.  There are several goals that the patient must achieve while in hospital before they can be discharged.

 How long will the patient need to recuperate?

Usually, the patient has to stay in bed on the day of the operation and can get up and sit in a chair by next morning. By evening, they can usually walk with the help of a walker. Knee replacements are being performed through smaller incisions today, through the Minimally Invasive Approach, and this newer approach has drastically reduced the recovery time.

Everyone heals from total knee replacement surgery at a different pace. In most cases, however, the patient is likely to use a walker or crutches for three to four weeks after the operation. They will then advance to walking with a cane and gradually progress to walking with no support.  In general, most patients are close to full recovery after ten to twelve weeks.

How long will I be on pain medication after total knee replacement surgery?

The patient will require a strong pain killer or analgesic – usually a narcotic – immediately after the operation. This is administered by means of a pump so that there is a slow but continuous flow of the medicine through the patient’s vein. Gradually, as the pain lessens, the injectable pain killer is replaced by oral medicines. Over four to six weeks, the requirement for strong pain killers should come down. Patients on blood thinners are advised caution when taking some varieties of pain killers.

What activities are permitted following total knee replacement surgery?

On recovery, one may return to most activities, including walking, climbing a flight of stairs, gardening, and golf. Some of the best activities to help with motion and strengthening are swimming and an exer-cycle.

What activities should I avoid after total knee replacement surgery?

One should avoid impact activities, such as running and jogging, and vigorous racquet sports like squash or tennis.

When can I return to work after total knee replacement surgery?

When you can return to work after total knee replacement surgery depends on your profession. If your work is sedentary, you may return to work as early as two to four weeks after the operation. If your work is more rigorous, you may require more time, sometimes up to twelve weeks before you can return to full duty.

When can I travel after total knee replacement surgery?

The patient is allowed to travel post-op as soon as they feel comfortable. It is recommended that they get up to stretch or walk at least once in an hour, every hour, when taking long trips. This is important to help prevent blood from clotting. Long flights (or long car rides, for that matter) may increase the risk of a blood clot. Often, in some cases, the use of a blood thinner such as aspirin may be indicated after consultation with a physician.

Will an implant set off a metal detector say, at an airport?

Since knee implants are made of metal, there’s a chance they could set off metal detectors; whether it actually does so depends, of course, on the type of implant that has been put in and the sensitivity of the security checkpoint equipment. It is customary to provide the patient who has undergone a TKR with a special card or certificate to keep with oneself, explaining that they have a knee implant.

When can I start driving after total knee replacement surgery?

Driving is not recommended for at least eight weeks after the operation, especially if one is on a course of strong painkillers like narcotics.

How long will my new knee last and can a second replacement be done?

A joint implant’s longevity will vary from patient to patient. All implants have a limited life expectancy, and how long they last would depend on an individual’s age, weight, activity level and medical condition. By and large, over 90% of knee replacements will be functioning well even 10 to 15 years after the operation. With continued improvements in knee replacement technology, a new knee may soon last well beyond this time period.

Can a knee be ‘partially’ replaced?

Some patients can be suitable candidates for a partial knee replacement – or a ‘Mini Knee’- if the arthritis is limited to only one compartment of the knee with the cartilage in the other half being in good condition. There must also be no instability of the knee. The partial knee replacement is a shorter surgery and therefore has a quicker recovery time.

  • Ravinder

    I need some more insight about total knee transplantation. about its effect over other joint above and below knee ie ankle joint and also over thigh joint .

    • India.com Health

      Ravinder, can you please post a question on our ‘Ask an expert’ section?