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Knee Replacement


Knee Arthroplasty, also known as Knee Replacement, is a surgical procedure that replaces an arthritic knee joint or its part with an artificial joint. The primary goals of this surgery are to alleviate pain, restore function, and preserve knee anatomy.

The surgery is usually recommended for older patients who suffer from pain and a loss of function due to arthritis, especially when other conservative treatments have proven unsuccessful.

Total knee replacements are considered one of the most successful medical procedures. The surgery typically takes between one and two hours and involves replacing the ends of the femur (thigh bone) and tibia (shin bone) with a metal surface and a plastic spacer between them. In many cases, the patella (kneecap) surface is also replaced. The prosthesis replicates the knee’s natural ability to roll and glide smoothly as it bends.

In cases of less extensive knee damage, a partial knee replacement or unicompartmental knee replacement can be performed to replace only one segment of the joint.

While successful knee replacement surgery offers excellent benefits, it is essential for patients to take care of their new artificial knee by avoiding movements that may stress or damage its components. With proper care, patients’ efforts should be rewarded for many years to come.


Please find below more detailed information on the knee arthroplasty procedure, including what to expect prior to, during, and after the surgery, as well as information on the recovery period.

Indications and Contraindications


The most common indication for knee replacement (knee arthroplasty) is degenerative arthritis (osteoarthritis) of the knee joint. This type of arthritis is generally associated with ageing, congenital abnormalities of the knee joint, or prior trauma to the knee.

Other conditions that may necessitate a joint replacement include avascular necrosis, osteochondritis, past infection, and inflammatory arthritis.



While knee arthroplasty does not have any absolute contraindications, it is important to be mindful of certain relative contraindications, including cases involving skeletally immature patients and individuals with active sepsis joint infections, poor bone stock or patients with general conditions precluding any surgery.

Benefits and Risks

Benefits of Knee Arthroplasty:

  • Pain Relief: arthroplasty effectively alleviates chronic knee pain, improving the patient’s overall quality of life.
  • Improved Mobility: Patients experience enhanced joint mobility and functionality, allowing them to perform daily activities with greater ease.
  • Enhanced Quality of Life: The procedure often enables individuals to return to recreational activities, such as walking, cycling, and swimming, which may have been limited by knee pain.
  • Correction of Deformities: In case of total knee replacement, it can correct knee joint deformities, such as bow-legged or knock-kneed alignment.
  • Prevention of Secondary Damage: By addressing knee arthritis or joint damage, the surgery helps prevent further degeneration and secondary issues in the knee.
  • Long-Term Durability: Modern knee implants are designed to be durable and provide long-lasting relief, with many patients enjoying improved knee function for decades.

Risks of Knee Arthroplasty:

  • Complications from Anesthesia: Patients may experience complications related to anaesthesia.
  • Surgical Risks: As with any surgery, there are general surgical risks, including infection, blood clots, anesthesia-related complications, and post-operative pain.
  • Stiffness or Reduced Range of Motion: Some patients may experience post-operative stiffness or a limited range of motion, which may require intensive rehabilitation.
  • Nerve or Blood Vessel Damage: In rare cases, there is a risk of nerve or blood vessel injury during surgery.
  • Rehabilitation Challenges: Successful recovery and rehabilitation require active patient participation, and non-compliance or inadequate rehabilitation can lead to suboptimal outcomes.
  • Implant Loosening: Knee implant components may loosen over time, potentially causing pain or instability.
  • Implant Wear: Over time, the knee implant may wear out, which could require revision surgery.
  • Progression of arthritis: In case of partial knee replacement, there might be progression of arthritis in other parts of the joint, necessitating revision to total knee replacement.


Patients should discuss the potential benefits and risks of knee replacement with their healthcare provider. The decision to undergo the procedure should be based on individual medical history, condition, and the expertise of the surgical team.

Surgical Approach

Knee arthroplasty can be performed through various approaches. Total Knee Replacement typically involves a front incision, while Unicompartmental Knee Replacement is used for limited knee damage, requiring smaller incisions. The choice of approach depends on the patient’s condition and the surgeon’s expertise, with Total Knee Replacement being the most common method for comprehensive knee joint replacement.

Knee Arthroplasty Pre-Surgery Information

Prior to knee arthroplasty surgery, the following procedures and preparations will take place:

  1. Patient Evaluation: A thorough assessment of the patient’s overall health, medical history, and orthopaedic condition. When necessary, your health might need optimisation and we may refer you to another specialist.
  2. Medications: Inform your healthcare provider about any medications you’re taking, as some may need to be adjusted before surgery. You should stop taking aspirin or anti-inflammatory medications 10 days prior to the surgery. Also, you should discontinue any naturopathic or herbal medications during this period.
  3. Imaging: X-rays, CT scans, and MRIs are used to evaluate the extent of damage and plan the surgery. CT scans are especially helpful in planning the surgical steps.  
  4. Skin preparation: The night before and on the morning of the operation, you will be asked to wash the leg with a sponge provided at the pre-admission clinic. If there is any suspicion of an iodine allergy, a Betadine Skin test might be used.
  5. Bowel Prep: Glycerin suppositories will be provided at the pre-admission clinic, and you will need to administer them the evening prior to the surgery. An instruction leaflet will be given to guide them.
  6. Patient education: During a physiotherapy assessment, a qualified physical therapist will provide you with personalised instructions on gait training, the use of crutches, and pre- and postoperative exercises. You will be fitted with crutches to take home and practise before the surgery.

On the day of the Surgery

  • Surgical paperwork will be administered by the nurses, and the anaesthetist will meet with the patient to ask a few questions.
  • A hospital gown will be given, and the operation site will be shaved and cleaned.
  • Betadine skin prep will be applied to the area above the operation site and wrapped.
  • All x-rays are to be sent with the patient to the theatre.

Knee Arthroplasty Surgical Procedure

Knee arthroplasty, whether total or partial knee replacement, is performed under spinal or general anaesthesia. The entire procedure typically takes up to two hours.

Step 1: Bone Preparation

An incision is made to expose the bones of the knee joint. The damaged cartilage surfaces at the ends of the femur (thigh bone) and tibia (shin bone) are carefully removed along with a small amount of the underlying bone.

Step 2: Implant Positioning

Specialised jigs are used to precisely cut the femur and tibia at the appropriate angles. In our practice, many knee surgeries are performed with the use of a specialized robot for superior precision. Test components are then inserted to check the accuracy of the cuts and determine the thickness of plastic required to be placed between the two components. Each knee is unique to the patient, and the knee replacement implants come in various sizes to cater to individual needs. If there is more than the standard amount of bone loss, additional pieces of metal or bone may be added. Depending on the condition of the knee, the patella (kneecap) may also be replaced.

Step 3: Resurfacing the Kneecap

In some cases, the undersurface of the kneecap is cut and resurfaced with a plastic button. However, not all knee replacement surgeries involve this step; it depends on the specific case and the patient’s needs.

Step 4: Spacer Insertion

A medical-grade plastic spacer is carefully inserted between the metal components. This spacer serves as a smooth, gliding surface, allowing the knee joint to move freely and function properly.


Final Steps

After these steps are completed, the knee is thoroughly checked to ensure that all components are correctly positioned and working as intended. The knee is then meticulously closed, dressed and bandaged, and the patient is carefully monitored during recovery.

Knee Arthroplasty Post-Surgery Information

Immediate Post-Surgery:

Following the surgery, patients will be taken to the recovery room for monitoring. Once their condition stabilises, they will be transferred to the ward.

The patient will be set up with a button for self-administered pain relief through a machine called a PCA machine (Patient-Controlled Analgesia). It is crucial for patients to use the PCA machine as prescribed by their healthcare provider to avoid overmedication.

Patients will be encouraged to start moving their knees and walking within a day or two of the surgery. The surgical wound dressing will usually be reduced on the second-day post-op to make movement easier. A physiotherapist will be available to guide them through exercises and assist with rehabilitation and mobility.

The expected hospital stay after the surgery is approximately three to five days.

Discharge: Depending on individual needs and situations, patients may be discharged home or transferred to a rehabilitation hospital. It is essential to continue with the prescribed physiotherapy exercises for a successful recovery.


The Recovery Process:

Following discharge, patients may require a walker or crutches for about six weeks. As their leg gains strength and control, they can transition to using a walking stick under the guidance of a healthcare provider.


Regular follow-up appointments with the team will help monitor your progress and address any concerns:

  • 1 week postop: for wound check,
  • 2 weeks postop: for suture removal
  • 6 weeks postop: for x-ray assessment of healing and your progress,
  • Later at 3, 6, 9, 12 months postop and further annually an x-ray will be mandatory.


Patients may resume driving around the six-week mark, but only when they feel confident that they’ve regained leg control. More demanding physical activities, such as sports, may resume comfortably after three months.

The degree of knee flexion will vary from patient to patient, but ideally, by six weeks, the knee should be able to bend to about 90 degrees. The goal is to achieve a range of movement between 110 and 115 degrees after surgery. This goal should be discussed with and determined by your healthcare provider.

Upon returning home, an occupational therapist will assess the patient’s living space and provide necessary precautions. This may include installing rails in the bathroom or adjusting sleeping arrangements if there are stairs in their home.


If patients are worried about their level of pain, experience significant bleeding, or notice fever or redness around the surgical site, they should contact the office immediately. If assistance is needed after hours, patients can contact the hospital where the surgery was performed, and they will contact Professor Al Muderis on their behalf.

Norwest Private Hospital: (02) 8882 8882

Macquarie University Hospital: (02) 9812 3000

This treatment could be eligible for our No 'Out-of-Pocket' Expenses Program

For further information, click here or to check your eligibility, please contact our team.