Robotic Arm Assisted Partial Knee Replacement Surgery

Drs Baird, Fassina and Munt were integral in introducing Mako Robotic Arm Assisted Joint Replacement Surgery to South Australia. This innovative and accurate option offers patient specific management of arthritic knee and hip conditions. Robotic Assisted Joint Replacement Surgery has been used throughout the world over the last 10 years with excellent patient outcomes.

A Robotic Arm Assisted Partial Knee Replacement is a minimally invasive procedure for those suffering with painful arthritis of the knee. It is performed using a surgeon controlled Robotic Arm, enabling our team of specialists to treat a patient’s specific knee condition with precision.

The Robotic Arm allows the surgeon to accurately resurface only the diseased portion of the knee, saving as much of the original knee as possible — including healthy bone and ligaments.

This minimally invasive approach enables our surgeons to help you strive for a more natural feeling knee.

A Robotic Arm Assisted Partial Knee Replacement can be performed on any one of the three knee compartments: the inner side (medial), behind the kneecap (patellofemoral), or outer side (lateral) compartments, known as a unicompartmental procedure, or it can be performed on both the medial and patellofemoral portions of the knee together, which is known as a bicompartmental procedure.

All people have unique anatomy (the way your bones, joints, muscle and soft tissues are made). Mako Robotic arm assisted surgery references your unique anatomy in order to plan and implement a patient specific partial knee replacement. This process involves

Patient Specific Planning:

Before surgery, a CT scan is taken of your knee, and a 3-D anatomical model is created. This allows the surgeon to plan the size, placement and alignment of your knee implants prior to surgery, and helps to accurately position them.

Functional Implant Positioning:

During your surgery, your knee is taken through a range of movement to assess how it moves and loads. This helps to determine where the implants need to be placed for your unique anatomy to result in the best outcome possible (to reduce load, wear and to increase lifespan of the implant).

Robotic Arm Assisted Bone Preparation:

The robotic arm allows the surgeon to accurately and reproducibly carry out the patient specific plan. Diseased bone is accurately removed by a high speed burr that is controlled by the surgeon at all time. The robot sets up boundaries that cannot be broken hence protecting the healthy tissues inside of the knee. The robot also gives tactile, visual and auditory feed back to the surgeon when the boundaries are approached. If the surgeon does try to “push through” the boundary, the power to the robotic arm will cut off preventing any injury to the non-diseased bone, cartilage and/or soft tissues.

The Benefits of a robotic arm assisted partial knee replacement are:

Minimally invasive

A small incision can be made to allow access into the joint. Direct visualisation of structures inside of the knee is not necessary as the virtual boundaries set up by the robot helps to ensure only diseased tissue is removed.

Fast recovery

There is a growing body of evidence to support the use of robotics in joint replacement surgery. Many aspects of patient outcomes have been investigated and published in peer reviewed journals as well as presented at international conferences.

Some early and promising results include:

  • In a study by Borus et al, Less physiotherapy was required for UKA patients compared with TKA patients to reach the same functional goals (ROM 5-115, recovery of flexion and extension strength to 4/5 of pre-operative strength, 100m of gait with minimal limp and no assistive device, able to ascend and descend stairs with step over gait and good control) ISTA KYOTO Japan.
  • Zuiderbaan et al reported on the “forgotten knee score”. This is a scoring system used by researchers to assess how “normal” a knee feels, following joint replacement surgery. This study found patients who undergo UKA are better able to “forget” their artificial joint in daily life compared to patients with similar health status undergoing TKA.

Ultimately the results that each individual experiences will be determined by many factors specific to their condition and treatment. Please discuss your goals with one of our trained surgeons.

Little post-operative pain

  • Factors leading to little post operative pain include:
  • A small incision generally results in little post operative pain.
  • During knee replacement surgery it is common practice to use a tourniquet to control bleeding. MAKOplasty® allows our surgeons to limit the use of such a device to only a short period of time.  This reduces the damage to the soft tissues of the thigh and leg. It also allows for the control of bleeding within the operative site at the time of surgery. This can reduce postoperative bruising, bleeding and swelling.
  • With small incisions, the same dose of local anaesthetic results in a higher concentration at the operative site.  This higher concentration of local anaesthetic results in longer lasting pain relief.

Evidence-based results

A list of independent studies about MAKOplasty® and it’s results can be found in the Resources and Links section of this website.

  1. Study evaluating 201 MAKOplasty patients (224 knees) who had partial knee resurfacing with RESTORIS® MCK medial onlay implants.
  2. Roche MW, Coon T, Pearle AD, Dounchis J. Two year survivorship of robotically guided medial MCK onlay. 25th Annual Congress of ISTA, October 3-6, 2012, Sydney, Australia.
  3. Kreuzer S, Conditt M, Jones J, Dalal S, Pourmoghaddam A. Functional recovery after bicompartmental arthroplasty, navigated TKA, and traditional TKA. 25th Annual Congress of ISTA, October 3-6, 2012, Sydney, Australia.

Patients with the best outcomes typically have osteoarthritis in one or two parts of the knees. These patients often share the following characteristics:

  • Knee pain with activity, usually on the inner knee and/or under the kneecap
  • Start-up knee pain or stiffness when activities are initiated from a sitting position
  • Failure to respond to non-surgical treatments or non-steroidal anti-inflammatory medication
  • Pain at night

As with any surgery there are associated risks to a robotic assisted partial knee replacement. The general complications of any surgery include:

  • Deep vein thrombosis (blood clot legs) or pulmonary embolus (blood clot lungs)
  • Blood loss requiring transfusion
  • Heart attack, strokes, kidney failure, pneumonia, bladder infections
  • Complication from nerve blocks such as infection or nerve damage
  • Anaesthetic complications including nausea and vomiting

The complications specific to knee surgery include:

  • Infection
  • Dislocation
  • Damage to nerves or blood vessels
  • Wound irritation or breakdown
  • Patella instability (kneecap can move out of place)
  • Failure to relieve pain
  • Fracture through pin sites
  • Wear of the new joint and revision surgery for this or progression of your arthritis
  • Stiffness in the knee
  • Numbness and tenderness around your wound and difficulty kneeling

Preparing for your Robotic Assisted Partial knee replacement

Preparation begins prior to your admission to hospital. Your surgeon will discuss your surgery and what to expect.

Arrangements should be made in advance to prepare for your recovery including:

  • Ensuring your home is free from tripping hazards.
  • Ensuring regularly used items are easily accessible.
  • Arranging to have someone at home with you or to check in on you when you are discharged.
  • A referral to the pre-admission service at the hospital you are having your surgery at can be very useful in helping you plan your transition home following your hospital stay/

Your surgeon may refer you to have:

  • Routine blood tests and other investigations prior to your surgery.
  • A pre-rehabilitation physiotherapy review to ensure you are as fit as possible prior to your surgery.
  • A review by peri-operative physician, if you have medical problems that need to be managed around the time of your surgery.

You will be given instructions regarding your medications and it is important you follow these. These may include:

  • Cease blood thinning medication such as aspirin and anti-inflammatory medications up to 10 days prior to your surgery.
  • Cease naturopathic or herbal medications 10 days prior to your surgery.
  • Ceasing certain medications used to treat inflammatory arthritis such as Rheumatoid arthritis.

Certain lifestyle risk factors can slow your healing following your surgery. In preparation for your recovery aim to:

  • Eat healthy
  • Quit smoking
  • Limit alcohol intake
  • Reduce weight if overweight (follow medical advice on safe exercise prior to and following surgery)

Remember to bring your x-rays with you to hospital.

Post surgery

Following your surgery, you will usually remain in hospital for 3 days. In this time, you may require antibiotics and pain relief. A physiotherapist will start you moving and help you with post-operative exercises as soon as your are assessed as being safe to move, which in most cases is the day of the surgery. It is important you follow the instructions of the physiotherapist to ensure you get the best out of your new knee.

You will need to use a walking aid initially following the surgery. Once you are assessed as safe, you can also stop using this.

On discharge, you will be given an appointment to see your surgeon as an outpatient. You will need to continue physiotherapy as instructed.

Recovery and wound care:

Sutures are usually dissolvable but if not will need to be removed 10-14 days after surgery.
Your dressing is water proof and allows you to shower as usual. Your surgeon may have some particular instructions about your wound care.

Avoid rubbing creams or lotions on your leg until you have discussed this with your surgeon
Driving can be recommenced following discussion with your surgeon

Hydrotherapy should not commence before 4 weeks, or after your surgeon tells you so.

Other precautions:

If you are having procedures such as dental work or other surgery, you should consult your surgeon who may recommend you take antibiotics before and after your procedure to prevent infection in your new prosthesis. All non essential dental work should be avoided for 3 months following your new joint replacement.
Your new prosthesis may cause the metal detector to alarm at airports. A letter from your surgeon is generally not required prior to travel.
Your surgeon will continue to follow your progress and how you and your new joint is functioning as time passes. Regular reviews and X-rays will be performed to ensure that you are performing well.

Robotic arm assisted total knee replacement surgery is a patient specific procedure for those suffering from painful knee arthritis. It is performed using the same surgeon controlled Robotic arm technology that Drs Fassina, Munt and Baird have been utilising since 2015. Globally this system has assisted with over 100 000 robotic arm assisted hip and knee procedures.

This innovative surgical treatment now also allows our surgeons to achieve consistently reproducible precision in total knee replacement surgery.

All people have unique anatomy (the way your bones, joints, muscle and soft tissues are made). Mako Robotic arm assisted surgery references your unique anatomy in order to plan and implement a patient specific knee replacement.

Robotic arm assisted total knee replacement surgery scans

Enhanced Patient Specific Planning:

Before surgery a CT scan is performed on your knee joint. To help understand your unique alignment, your hip and ankle are also scanned. The information obtained from this CT scan allows for a 3-Dimensional model of your knee joint to be created. This allows the surgeon to pre-operatively plan the size and orientation of your knee replacement.

Functional Implant Positioning

During surgery your knee joint is placed through a range of movement and the overall alignment, ligament tension and the way the knee moves is assessed. Precise movements of the knee replacement components can then be made to best match your anatomy. The robotic software provides real time information to allow accurate implant positioning. This occurs before bone preparation occurs.

Robotic Arm Assisted Bone Preparation

The Mako Total knee application does not require cutting blocks, sizing guides or intramedullary rods for bone preparation. The surgeon controlled robotic arm creates a virtual boundary to assist with the removal of only the damaged bone and cartilage while protecting to soft tissues such as the PCL and the blood vessels and nerves at the back of the knee. It provides the surgeon with tactile feedback, 3-D visualisation and auditory guidance to facilitate precise bone removal.

Robotic arm assisted surgery bone preparation scans

Finally once all components have been implanted, a summary screen allows your surgeon to confirm that your results are accurate and according to the pre-operative plan.

The Mako total Knee system uses the Triathlon Total knee replacement. This prosthesis is manufactured by Stryker, one of the worlds largest orthopaedic companies. The triathlon has over 10 years of proven performance in both Australia and New Zealand. The 10 year survival rate is one of the best seen being 96.6% on the Australian joint replacement registry and 97.4% on the New Zealand Joint replacement registry after 10 years. (1,2).

Mako robotic-arm assisted Total Knee Arthroplasty has the potential to increase the accuracy of TKA bone cuts and component placement to plan, even for an experienced user of manual instrumentation who is new to robotic technology.(4)


Comparing the means for all six matched pairs (n=6), RATKA final bone cuts and final component positions were as or more accurate to plan than MTKA control, for 11/12 and 5/5 measurements, respectively, and all (17/17) measurements when comparing the last three matched pairs (n=3).On average, RATKA (n=6) final bone cuts and final component positions were 4.2 and 3.2 times more accurate to plan than the MTKA control, respectively.


Comparing the standard deviations for all six matched pairs (n=6), RATKA final bone resections and final component positons were as or more precise to plan than the MTKA control on all femoral and tibial V/V measurements, and all measurements when comparing the last three matched pairs (n=3).

On average, RATKA (n=6) final bone cuts and final component positions were 5.0 and 3.1 times more precise to plan than the MTKA control, respectively.

Adequate soft tissue protection is achieved using Mako robotic-arm assisted surgery for Total Knee Arthroplasty. It offers protection of the medial collateral ligament (MCL), lateral collateral ligament (LCL), posterior cruciate ligament (PCL), and patellar ligament with no visible evidence of disruption of any of the ligaments. Tibial subluxation was not required for tibial cutting, which may reduce ligament stretching. All cases were left with a bone island on the tibial plateau, which protected the PCL. In addition, patella eversion was not required for visualization.(5).

Further reading


The information held on this page is for educational purposes only.

Individual results may vary from patient to patient and not all patients are suitable for this treatment. Please consult your specialist prior to considering any medical intervention.

As with any surgery, knee replacement surgery has serious risks associated with it and these should be considered prior to deciding to proceed.

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