Knee Replacement Surgery

Knee replacement is done when the surfaces in the knee are worn out and painful. These days it is not as painful as it used to be thanks to better anaesthetic techniques.

Better materials and implantation methods also mean that knee replacements will last longer and may be ok for some younger (and older) people than before.

When arthritis severely damages the surfaces of the knee walking, getting out of a chair, climbing stairs and driving for long periods may be difficult. Eventually there may even be pain at night that wakes you. Wear of one surface more than another may cause a gradual worsening of the alignment of the limb.

Initially non-surgical measures like NSAIDs, activity modification and walking aids are insufficient to relieve pain and achieve function. Knee replacement may then be considered.


The knee is the largest joint in the body where the ends of the femur and tibia articulate. The patella sits at the front of these two bones and act as a pulley for the quadriceps muscle to work around. The ends of the bones are covered in articular cartilage. It is the wearing of the articular cartilage that results in arthritis.

The menisci are C-shaped fibrocartilage discs that act as shock absorbers in the knee. A thin lining of tissue called synovium surrounds the joint and produces lubricating fluid.

The knee is the largest joint in the body where the ends of the femur and tibia articulate. The patella sits at the front of these two bones and act as a pulley for the quadriceps muscle to work around. The ends of the bones are covered in articular cartilage. It is the wearing of the articular cartilage that results in arthritis.

The menisci are C-shaped fibrocartilage discs that act as shock absorbers in the knee. A thin lining of tissue called synovium surrounds the joint and produces lubricating fluid.

The main types of knee arthritis are osteoarthritis, rheumatoid arthritis and post traumatic arthritis.

Preparing for Surgery

Evaluations and Tests

Dr Simon Hutabarat may recommend that you see your GP or another specialist to assess your general health before surgery. He or she will identify any problems that may interfere with the procedure. If you have certain health risks, a more extensive evaluation may be necessary before surgery.

To help plan your procedure, Dr Simon Hutabarat may order preoperative tests. These may include blood tests or an electrocardiogram (ECG). You may be seen at a preadmission clinic where staff will review your results.

A CT scan is often used to take a high quality image of the knee and an image from the hip to the ankle to assess the alignment of the limb. This must be done at least 4 weeks prior to the actual procedure.

The CT images are used to ‘perform’ a virtual operation and make adjustments as required to optimise the sizing and positioning of the implant.

When the best placement of the implant is achieved 3D printed guides are made that are specifically designed to fit the individual patient. The sterilised guides are placed in the knee during surgery to reproduce the optimal cuts planned for the knee.

Feel free to discuss your concerns with Dr Hutabarat. Never hesitate to ask questions when you do not understand. The more you know, the better you will be able to manage the changes that knee replacement surgery will make in your life.

Realistic Expectations

An important factor in deciding whether to have knee replacement surgery is understanding what the procedure can and cannot do. Most people who undergo knee replacement surgery experience a dramatic reduction of knee pain and a significant improvement in their ability to perform the common activities of daily living.


With normal use and activity, the polyethylene bearing between the knee replacement implants begins to slowly wear. Excessive activity or being overweight may speed up this normal wear and cause the knee replacement to loosen and become painful. Therefore, most surgeons advise against high-impact activities such as running, jogging, jumping, or other high-impact sports.

Realistic activities following total knee replacement include unlimited walking, swimming, golf, driving, hiking, biking, dancing, and other low-impact sports.

With appropriate activity modification, knee replacements can last for many years.

  • Preparing Your Skin

    Your skin should not have any infections or irritations before surgery. If either is present, contact the hospital or the rooms for treatment to improve your skin before surgery. 

    If you have particularly dry flaky skin it may be an idea to moisturise it to improve its condition in the weeks prior to surgery. Organisms live on our skin. We do not want them floating around the operating room on tiny flakes of your dry flaky skin.

  • Blood Management

    You may be advised to improve your ability to produce blood cells prior to surgery. This can be done several ways. If you are not able to have blood products for any reason please inform Dr Hutabarat.

  • Medications

    Tell the practice about the medications you are taking. The practice or the preadmission clinic staff will advise you which medications you should stop taking and which you can continue to take before surgery.

  • Weight Loss

    If you are overweight, you may be asked to lose some weight before surgery to minimise the stress on your new knee and possibly decrease the risks of surgery.

  • Dental Evaluation

    Although infections after knee replacement are not common, an infection can occur if bacteria enter your bloodstream. Because bacteria can enter the bloodstream during dental procedures, major dental procedures (such as tooth extractions and periodontal work) should be completed before your knee replacement surgery. 

  • Urinary Evaluation

    Individuals with a history of recent or frequent urinary infections should have a urological evaluation before surgery. Older men with prostate disease should consider completing required treatment before having surgery.

  • Specialised Geriatric Assessment

    Some elderly people may require specialised geriatric assessment preoperatively or postoperatively. If you think either yourself or your relative may benefit from this, please notify Dr Hutabarat’s staff. 

    There are several geriatricians and rehabilitation experts at the facilities at which surgery or recovery may take place. The practice has considerable experience in managing these issues and Dr Hutabarat has given many talks on a national level regarding orthopaedic management of elderly patients.

  • Social Planning

    Although you will be able to walk with crutches or a walker soon after surgery, you will need some help for several weeks with such tasks as cooking, shopping, bathing, and laundry.

    If you live alone, a discharge planner or the rehabilitation team at the hospital can help you make advance arrangements to have someone assist you at your home. A short stay in a rehab facility during your recovery after surgery also may be arranged.

  • Home Planning

    Several modifications can make your home easier to navigate during your recovery. These are more likely to be required in the very frail patient who is still in rehab postop. A discharge planner and a home visit prior to discharge may be used to determine what is required. The following items may help with daily activities:

    • Securely fastened safety bars or handrails in your shower or bath
    • Secure handrails along all stairways
    • A stable chair for your early recovery with a firm seat cushion, a firm back, and two arms
    • A raised toilet seat
    • A stable shower bench or chair for bathing
    • A long-handled sponge and shower hose
    • A dressing stick, a sock aid, and a long-handled shoe horn for putting on and taking off shoes and socks without excessively bending your new knee
    • Tongs or a reacher
    • Removal of all loose carpets and electrical cords from the areas where you walk in your home


Admissions Instructions

Your knee replacement will be performed as an inpatient. Generally admission is on the day of surgery. 

Be sure to inform the team of any medications or supplements that you take. You may need to stop taking some of these before surgery.

The hospital will contact you ahead of time to provide specific details of your procedure. Make sure to follow the instructions on when to arrive and especially on when to stop eating or drinking prior to your procedure.


Before your surgery, a member of the anaesthesia team will talk with you. Knee replacement can be performed under a combination of local, regional, or general anaesthesia:

  • Local anaesthesia numbs just your knee
  • Regional anaesthesia numbs you below the waist
  • General anaesthesia puts you to sleep

Dr Hutabarat and your anaesthetist will talk to you about which method is best for you.

The Procedure


In a total knee replacement damaged bone and cartilage is removed and replaced with prosthetic components.

The path a surgeon takes into the body is known as the approach. The three main approaches used for knee replacement are the medial parapatellar, lateral parapatellar and subvastus approaches. Each of them have different pros and cons. The medial parapatellar approach is generally the commonest approach used for knee replacement.


Once the approach has been completed and adequate access has been achieved, the sterile 3D printed jigs are fitted to the knee and double checked to ensure alignment is optimal.

Bone resections are then performed and after trialling and adjusting ligament tensions, the prosthetic components are either cemented or press fit in place into the tibia, femur and patella. A polyethylene spacer is locked in place on the tibia to allow a smooth low friction articulation with the femoral component.

Further infiltration of local anaesthetic is then given before the knee is closed up and a dressing applied.

Sometimes a special suction dressing and/or drain is placed to drain away any excess blood from the wound.

After surgery, you will be moved to the recovery room where you will have an x-ray taken and where you will remain for several hours while your recovery from anaesthesia is monitored. After you wake up, you will be taken to your hospital room.


The success of your surgery will depend in large measure on your weight and how well you follow your instructions regarding home care during the first few weeks after surgery.

  • Wound Care

    You may have stitches or staples running along your wound or a suture beneath your skin. The stitches or staples will be removed approximately 2 weeks after surgery.

    Avoid getting the wound wet until it has thoroughly sealed and dried. You may continue to bandage the wound to prevent irritation from clothing or support stockings.

  • Diet

    Some loss of appetite is common for several weeks after surgery. A balanced diet, often with an iron supplement, is important to promote proper tissue healing and restore muscle strength. Be sure to drink plenty of fluids.


Exercise is a critical component of home care, particularly during the first few weeks after surgery. You should be able to resume most normal light activities of daily living within 3 to 6 weeks following surgery. Some discomfort with activity and at night is common for several weeks.

Your activity program should include:

A graduated walking program to slowly increase your mobility, initially in your home and later outside.

Resuming other normal household activities, such as sitting, standing, and climbing stairs.

Specific exercises several times a day to restore movement and strengthen the knee. You may be able to perform the exercises without help, but you may have a physiotherapist help you at home or in a therapy centre the first few weeks after surgery

Possible Complications of Surgery

The complication rate following knee replacement surgery is low. Serious complications, such as joint infection, occur in less than 2% of patients. Major medical complications, such as heart attack or stroke, occur even less frequently. However, chronic illnesses may increase the potential for complications. Although uncommon, when these complications occur they can prolong or limit full recovery.

  • Infection

    Infection may occur superficially in the wound or deep around the prosthesis. It may happen while in the hospital or after you go home. It may even occur years later.

    Minor infections of the wound are generally treated with antibiotics. Major or deep infections may require more surgery and removal of the prosthesis. Any infection in your body can spread to your joint replacement.

  • Blood Clots (Deep Vein Thrombosis)

    Blood clots in the leg veins (DVT) are one of the most common complications of knee replacement surgery. These clots can be life-threatening if they break free and travel to your lungs (pulmonary embolism). Dr Hutabarat has a prevention protocol which may include blood thinning medications, support stockings, inflatable leg coverings, ankle pump exercises, elevation of the foot of the bed and early mobilisation. 

  • Clicking and Numbness on the Lateral (Outer) Side of the Incision

    It’s very common to sense clicking in the knee when you walk. This is due to separation and then contact between the plastic and metal components of the implant. This is totally normal. It may become less noticeable when the muscles return to a good level of tension.

    Some numbness on the lateral side of the scar is also inevitable. The area of numbness decreases over time to an area about the size of a 20c piece. Over time patients get used to this small area of numbness and it doesn’t trouble them.

  • Loosening and Implant Wear

    Over years, the knee prosthesis may wear out or loosen. This is most often due to everyday activity. It can also result from a biologic thinning of the bone called osteolysis. If loosening is painful, a second surgery called a revision may be necessary.

  • Other Complications

    Nerve and blood vessel injury, bleeding, fracture, and stiffness can occur. In a small number of patients, some pain can continue or new pain can occur after surgery. It’s important to maintain your bone quality as you get older to minimise the risk of fracture.

Avoiding Problems After Surgery

  • Recognising the Signs of a Blood Clot

    Follow Dr Hutabarat’s instructions carefully to reduce the risk of blood clots developing during the first several weeks of your recovery. He may recommend that you continue taking the blood thinning medication you started in the hospital. Notify your doctor immediately if you develop any of the following warning signs.

  • Warning signs of blood clots

    The warning signs of possible blood clot in your leg include:

    • Pain in your calf and leg that is unrelated to your incision
    • Tenderness or redness of your calf
    • New or increasing swelling of your thigh, calf, ankle, or foot

    Warning signs of pulmonary embolism. The warning signs that a blood clot has travelled to your lung include:

    • Sudden shortness of breath
    • Sudden onset of chest pain
    • Localised chest pain with coughing
  • Preventing Infection

    A common cause of infection following knee replacement surgery is from bacteria that enter the bloodstream during dental procedures, urinary tract infections, or skin infections.

    Following surgery, patients with certain risk factors may need to take antibiotics prior to dental work, including dental cleanings, or before any surgical procedure that could allow bacteria to enter your bloodstream. There are differing opinions regarding the taking of preventive antibiotics before dental procedures. Dr Hutabarat generally prefers antibiotic coverage for dental procedures where drilling or extraction may cause a shower of organisms into the blood stream.

  • Warning signs of infection

    Notify your doctor immediately if you develop any of the following signs of a possible knee replacement infection:

    • Persistent fever (higher than 38°C orally)
    • Shaking chills
    • Increasing redness, tenderness, or swelling of the knee wound
    • Drainage from the knee wound
    • Increasing knee pain with both activity and rest
  • Avoiding Falls

    A fall during the first few weeks after surgery can damage your new knee. You should use a cane, crutches, a walker, or handrails or have someone help you until you improve your balance, flexibility, and strength.

    Dr Hutabarat and your physiotherapist will help you decide which assistive aids will be required following surgery, and when those aids can safely be discontinued.

Other Precautions

Prior to discharge from the hospital, your physiotherapist will provide you with any specific precautions you should follow.


How Your New Knee Is Different

You may feel some numbness in the skin around your incision. You also may feel some stiffness, particularly with excessive bending. These differences often diminish with time, and most patients find these are minor compared with the pain and limited function they experienced prior to surgery.

Your new knee may activate metal detectors required for security in airports and some buildings. Tell the security agent about your knee replacement if the alarm is activated. You may ask for a card confirming that you have an artificial knee.

Protecting Your Knee Replacement

There are many things you can do to protect your knee replacement and extend the life of your implants. These include:

Participating in a regular light exercise program to maintain proper strength and mobility of your new knee. Cycling is an excellent form of exercise both before and after knee replacement.

Try and maintain your weight within a healthy weight range.

Take special precautions to avoid falls and injuries. If you break a bone in your leg, you may require more surgery.

Make sure your dentist knows that you have a knee replacement. Talk with your orthopaedic surgeon about whether you need to take antibiotics prior to dental procedures.

Dr Hutabarat may see you periodically for routine follow-up examinations and x-rays, even if your knee replacement seems to be doing fine. If there are problems outside these scheduled follow ups, please contact the rooms. We frequently fit patients in at short notice to deal with possible issues earlier rather than later.

Frequently Asked Questions

  • How long am I in for?

    For about 5-7 days. Some people may require rehabilitation in hospital thereafter for a further week or so.

  • What time will I need to come in?

    You will generally be called the night before surgery by a nurse at the hospital to tell you the time to come in. Generally the joint replacements occur earlier on the list.

  • How much does it cost?

    Surgeons charge different fees for many different reasons so it pays to ask around and get other opinions!  We do a quote for all our patients. Don’t be afraid to ask questions. We like questions and are happy to answer them.

  • When can I return to work?

    This depends upon the work, the level of its intensity and the individual. Generally most people can budget on return to work around about 3 months after surgery, maybe earlier if you work at a desk and can work from home.

  • When can I get it wet? Or swim?

    Generally wounds need to stay dry for two weeks and then we may give a bit more time as a precaution. Patients generally return to walking in the shallow end of the pool before swimming. It is generally advised to avoid the breaststroke kick when you do return to swimming.

  • What about timing for my holidays/travel?

    This is a very important question! It’s best to allow 3 months before a trip… again it depends on the situation.

This information has been adapted from information on the American Academy of Orthopaedic Surgeon’s website which may have other useful information on other orthopaedic topics. The information on Dr Hutabarat’s website is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance should consult Dr Hutabarat’s rooms for an appointment on 1800 686694 or via email (

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