KINEMATICALLY ALIGNED TOTAL KNEE REPLACEMENT SURGERY USING COMPUTER ASSISTED | PATIENT SPECIFIC | 3D TECHNOLOGY

At Midwest Orthopaedics, a total knee replacement procedure is performed using 3D-printed patient-specific instruments (PSI), 3D anatomical mapping tools, augmented reality, and the kinematic alignment (KA) knee replacement surgical approach.

A kinematically aligned total knee replacement aims to restore your natural knee motion and alignment by using advanced computer-assisted and patient-specific 3D technology. This technique differs from traditional knee replacement surgery, which relies on implant alignment guides that are based on the mechanical axis of the leg rather than the patient’s unique anatomy.

When performing your kinematically aligned, total knee replacement, Dr Singh will use 3D imaging to create a detailed map of your knee joint. This map is then used to design and create your patient-specific instruments (PSI) that will guide him during your procedure, ensuring a precise fit and alignment of the knee implant.

During your procedure, Dr Singh will make some small incisions and then use the patient-specific instruments to position your implant in accordance with your natural knee motion and alignment . The computer-assisted technology also provides real-time feedback in surgery on the alignment and positioning of your implant and it is this added support in surgical accuracy why Dr Singh performs all his total knee replacement procedures using advanced technology unless there is a specific reason not to.

Anatomy of the knee

Your knee is the largest and most complex joint in your body. It consists of three bones: the femur (thigh bone), the tibia (shin bone) and the patella (your kneecap). Knee movement is powered by the muscles in your thighs, with the biggest muscle being your quadriceps.

Your thigh muscles and the shin bones are connected by tendons and ligaments which work together to maintain your normal knee function and provide the stability required for you to get moving.

The surfaces on your kneecap, thigh, and shin bones, are coated with a smooth tissue called cartilage. This cartilage, together with a substance called synovial fluid acts as a protective ‘cushion’ in the knee, preventing your bones from rubbing against each other and stopping them from wearing down and becoming damaged.

Arthritis of the knee

Osteoarthritis is the most common form of arthritis in the knee. It is a degenerative, “wear-and-tear” type of arthritis that occurs most often in older people, although it can occur in younger people too. With osteoarthritis, your cartilage deteriorates, and your bones start to rub directly against each other causing pain. 

Osteoarthritis pain will often be felt in your thigh, and on the side of your knee which radiates through to your shin bone. It can occur in one knee or in both, and the symptoms and pain may come and go depending on the time of day and even with changes in the weather. Other symptoms may include stiffness and limping, a loss in flexibility and swelling. The pain can become worse over time, it can limit your range of motion, and is often extremely uncomfortable, reducing your ability to perform your normal day-to-day activities.

There are a variety of surgical and non-surgical solutions to treat arthritic knee pain. Treatment usually starts with simple measures such as the use of a walking stick, knee strengthening exercises and weight loss. Your General Practitioner may recommend joint supplements as a suitable first step for you, as well as prescription arthritis tablets called non-steroidal anti-inflammatory medication (NSAID’s).

If your pain however is no longer being relieved by the nonsurgical treatments, is occurring frequently, is interfering with your day-to-day activities, and reducing your overall quality of life, a total knee replacement procedure may be a viable treatment solution for you. 

Suitable candidates for a knee replacement

The goal of total knee replacement surgery is to improve your function in daily life so, if you have been consistently experiencing severe knee pain, have difficulty walking, reduced mobility and stiffness or a limited range of motion and if you are suffering from osteoarthritis and non-surgical interventions such as pain relief, physiotherapy and walking aids are no longer helpful, total knee replacement surgery may be an option for you.

It is important to understand however that total knee replacement surgery is an elective operation and whilst Dr Singh can advise and recommend options, the final decision must be yours. 

Benefits of a knee replacement

The main benefits of a successful total knee replacement include a significant reduction in the symptoms of arthritis including a reduction in knee pain, recovery of your mobility and an overall improvement in the quality of your life. Your everyday activities and your social life should no longer be limited by pain and reduced mobility once you have had total knee replacement surgery.

In addition, total knee replacement surgery that incorporates patient-specific cutting guides may also mean a shorter and less-invasive surgical procedure. This is because patient-specific cutting guides can reduce the number of steps required to perform total knee replacement surgery and potentially eliminate the need to insert guide rods into the thigh bone, resulting in less time spent in the operating room.

Prosthetic implants used in total knee replacement surgery

Total knee replacement surgery, (also called total knee arthroplasty surgery), involves removing the damaged bone and cartilage in your knee joints and replacing these worn-out surfaces with high-resistant metallic pieces, called the femoral component (highly polished Chrome Cobalt) and tibial baseplate (titanium alloy). 

Between these two components, a plastic tibial insert (polyethylene) is implanted which replaces your cartilage and synovial fluid function, allowing your thigh and shin bone to slide smoothly on each other again, and ultimately eliminate your pain and stiffness.

Dr Singh will usually use the GMK Sphere, medially stabilised knee implant in his total knee replacements as it is designed to provide a more natural motion, replicating this movement of your healthy knee. When your knee bends, the lateral (outer) side rolls back, while the medial (inner) side remains stable. The GMK Sphere implant allows stability on the inner side of your knee through a ball-in-socket mechanism which is essential for common activities such as going up and down stairs, sit to standing, getting into a car, and more demanding activities like shopping and gardening.

Mechanical and kinematic alignment knee replacement surgical techniques

Traditionally, total knee replacement surgery was performed using a mechanical alignment technique (or MA), which aims to give every patient a straight “knee alignment” after surgery. We all recognise however, that people look different, their faces and their bodies. It turns out that knees are also different in shape and in alignment, even when they are healthy, 

Some people have legs that are naturally ‘almost straight’ however, many peoples’ legs are naturally Varus (bowlegs), or Valgus (knock-knees), and for those patients, making their leg ‘straight’, when it is not normally, could actually make their pain and recovery worse following knee replacement surgery.

A kinematic alignment technique (or KA), which Dr Singh utilises in total knee replacement surgery, aims to restore the alignment of both your joint-line, and your leg alignment to recreate what you had had when your knee was still healthy. It uses computer-assisted technology and 3D mapping to analyse your unique anatomy, ligament function, and movement patterns. This technique also uses patient-specific instruments (PSI) and augmented reality technology to guide Dr Singh when placing the prosthesis. With kinematic alignment, your knee replacement is matched to your individual anatomy and can potentially make recovery easier and faster compared to traditional MA surgery.  A kinematic alignment technique may also improve your pain and, possibly, improve the biomechanics of walking and your daily activities following surgery.

Technology and knee replacement surgery

Technology plays an important role at Midwest Orthopaedics especially in total knee replacement procedures because of the added benefits it provides to our patients:

COMPUTER NAVIGATION AND AUGMENTED REALITY TECHNOLOGY 

Augmented reality (AR)-based navigation systems such as NextAR™ use smart glasses which are worn in the knee replacement surgical procedure. This technology allows Dr Singh to visualise his surgical actions which are ‘superimposed’ onto the operative field. This perception of a ‘real-life environment’ in surgery can enhance surgical precision as it enables Dr Singh to make data-driven decisions during your procedure.

The total knee replacement surgery process

1. GP REFFERAL – If you have knee osteoarthritis (OA), your GP will refer you to Dr Singh if they consider you may be a potential candidate for total joint replacement (TJR) surgery.  It is not clear which patients end up having this surgery.

3. PHYSICAL EXAMINATION – Dr Singh will perform a complete physical examination to confirm that you do not have any conditions that could interfere with the surgery or the outcomes.

4. GENERAL HEALTH – If you smoke, you should make every effort to STOP at least 2 weeks (or even longer) before your operation. Smoking increases your risk of infection and slows down wound healing. If you have ever needed an incentive to quit, having surgery is it!

5. MEDICATIONS – Provide Dr. Singh with a complete list of any medications you are taking especially, any blood thinning medications. He will inform you if you need to stop or change any medications prior to surgery.

6. CHECK YOUR PRIVATE HEALTH INSURANCE COVER – Call your private health insurance provider to check that you are covered for joint replacement surgery. Some common item codes to check with them include 48915, 49519, 49521 & 49524.

7. CT SCAN– Dr Singh will arrange for you to have a CT scan of your knee at least, 6 weeks prior to your surgery date for the engineers in Switzerland to create a 3D model of your knee and create your personalised surgical instruments.

10. EQUIPMENT REQUIREMENTS – Prior to your procedure, an Occupational Therapist from the hospital will call you to conduct a brief assessment of your post-op needs. This will include details regarding what equipment you will require to assist you during your rehabilitation, and how to safety proof your home.

11. PACK YOUR BAG FOR THE HOSPITAL – Be sure to pack a small bag of things to take with you to the hospital including your regular medications, some clean clothes, and your toiletries. Your hospital stay following a total knee replacement is usually 3 nights but may be longer, depending on your individual situation.

The surgical procedure

After total knee replacement surgery

Immediately after total knee replacement surgery, you will be wheeled into a recovery room on your ward bed and given oxygen to help you breath. Leads will be on your chest to monitor your heart rate, and an intravenous line (drip) will be in your arm which dispenses fluid and paracetamol for the first 24-36 hours following your procedure. 

When you wake up in the recovery ward, you may feel a bit groggy. Dr Singh and the hospital team will monitor you, checking your blood pressure, temperature, and pulse. Post-operative x-rays will be performed in recovery so that Dr Singh can check the position of your prosthesis and after 45 minutes – 1 hour, you will be transferred back to your room on the ward.

The nursing team at the hospital will help you perform your normal day to day activities as required. The hospital physiotherapists will also help you to achieve independence with the following post-surgery goals:

• Lifting your leg in and out of bed (using a small device)
• Walking with a frame
• Walking with crutches or a walking stick on a level surface
• Walking up and down stairs
• Getting in and out of a chair
• Your exercise program at home 
• Going to the bathroom

Your hospital stay following total knee replacement surgery is usually 3 – 5 nights, however, may be longer based on your individual situation. Dr Singh takes into consideration your age, general health, whether you have help at home, if your home has a lot of steps among other factors when determining your required stay in the hospital.

In the first week following surgery, you may experience:

SWELLING– From your thigh down into your foot is common. Swelling may increase for the first few days after surgery and will gradually lessen although some swelling can still be present for 12 months or so after surgery.

BRUISING – Bruising is common and can usually be found anywhere on your thigh and down into your foot. At times the bruising can be quite dramatic, but it will resolve. Bruising is the result of some residual bleeding making its way to the surface or, it can also come about from the blood thinning tablets you will be taking. 

BLISTERING – In some patients, blisters will develop near your incision. The blistering is usually due to surface fluid, and although they may look alarming, they are usually of no consequence. Blisters can be caused by the bandages rubbing on your skin or from tissue swelling. They may burst and leak fluid and can sometimes be large and alarming, but they are harmless, and will always resolve.

MUSCLE SORNESS – During surgery, some stretching and pulling on your muscles occurs. Your muscles can feel stiff and sore to touch with pain like a corked thigh. Walking and stretching can usually help alleviate this.

INCISION WARMTH – For some patients, the operated hip may radiate heat and feel very warm. This is because, part of the body’s natural healing process is to supply more blood to areas in the body that have been wounded, and it is the extra blood around the incision which creates the warm feeling.

For the first 2 weeks after surgery, your activity level is usually limited however you will be able to walk independently, use the bathroom and perform normal daily activities.

After 2 weeks, you will be able to engage in moderate activities, such as driving a car and climbing stairs.

Within 6 weeks, you should be able to resume most of your normal activities. 

Within 8 weeks you will have resumed most of your normal activities. Complete surgical healing takes 6 – 8 weeks but sometimes longer if the arthritis was very severe or the knee very deformed. 

Follow-up appointments with Dr Singh following total knee replacement surgery are 1 month, 3 months then, 12 months post-surgery. 

Potential surgery risks

The majority, (95%) of total knee replacements are performed without complication, resulting in a pain free knee which is stable and your everyday activities, like walking, will no longer be restricted by the severe pain. With technological advancements such as the custom-made, patient specific instrumentation, improved bearing surfaces of the implants and the utilisation of augmented reality, knee replacement outcomes should improve even further giving you a pain free knee that lasts for the rest of your life.

As with all surgeries however, there are certain risks and potential complications. The following is a list of possible complications, and the measures Midwest Orthopaedics uses to mitigate them from occurring:

Blood clots: Clots (deep venous thrombosis or DVT) can occur in the veins of the legs after any surgery. Occasionally these clots travel to the lungs causing a clot in the lung (pulmonary embolus or PE).  A pulmonary embolus has the potential to cause death so, if you develop pain or swelling in your calf post-surgery or find yourself suddenly short of breath, please contact Midwest Orthopaedics, the hospital, or your local GP immediately. 

To reduce the risks of clots forming, Dr Singh will prescribe aspirin to thin your blood and he uses special compression sleeves during and after your operation. The Midwest Orthopaedics team will also spend time educating you on calf muscle exercises to be performed after surgery and ensure the hospital team get you up and mobile as quickly as possible after surgery. 

Midwest Orthopaedics will also arrange an ultrasound of your legs prior to discharge to exclude the presence of any clots before going home.

Infection: This is a very serious complication which occurs in approximately 1% of cases. 

Although uncommon, the Midwest Orthopaedics team take the following precautions to further minimise this risk: 

• prior to surgery, your skin is tested to ensure resistant organisms are not present
• your limb is pre washed with Betadine prior to surgery
• intravenous antibiotics are used at the time of surgery 
• the surgical team are required to wear special, self-enclosed theatre gowns
• any infection that develops after surgery is treated immediately

Delayed infection has been reported years after joint replacement and appears to be related to the ability of the implants, in general, to harbor bacteria transported by the blood stream from other sites of the body. Bladder or kidney infections can be a source, but dental abscesses, infected ingrown toenails, or skin infections may also be a significant danger to a joint implant. If dental surgery, bladder surgery, bowel surgery or rectal surgery is planned, the surgeon or dentist should be informed that you have had a joint replacement. 

If an infection does occur, it is important to seek treatment immediately as it is often possible to save the prosthesis if treated early enough. If this is not possible, then it may be necessary to remove the prosthesis and give antibiotics through a drip for a six-week period.

A new prosthesis can usually then be re-implanted once the infection has resolved.

Fracture: Although rare, it is possible for the bones around the joint to break during or after surgery. Dr Singh avoids this risk by taking appropriate care during insertion and using a knee replacement system with many size options.

Prosthesis loosening: A small percentage of patients require revision surgery because of excessive wear or loosening of the prosthesis. This may cause pain and a limp, and the diagnosis can be confirmed with x-rays 

Post operative stiffness: In a small group of patients, (1-2%) the knee can remain quite stiff after total knee replacement surgery and further surgery may be required to resolve the stiffness.

To reduce the chance of the knee remaining stiff, Dr Singh adheres to the following surgical protocol:

• he uses a smaller incision and thereby less soft tissue destruction
• he mobilises your knee quickly after your procedure
• he does not use a tourniquet during surgery, 

Implant malposition: Despite the best intentions and effort, it is possible for a prosthesis to be inserted at a slight angle or rotated. To avoid this risk, Dr Singh utilises advanced software in the operating room during your procedure which assists him during the intra-operative assessment of your replacement.

Joint dislocation: Sometimes, the knee joint can dislocate because muscles and ligaments have not yet repaired themselves to provide support to the joint.

Allergies to metal: Metal allergies, particularly nickel, can occur in some people. The prostheses Dr Singh uses are made of titanium, chrome cobalt and polyethylene which do not contain nickel so should not cause an allergy.

The patients general and mental health: As with all surgeries, patients can develop problems such as a heart attack or stroke during or after an anaesthetic. This is often related to health problems present before the surgery though and is why Dr Singh arranges a specialist physician review prior to your procedure. 

Discovering any potential problems before surgery drastically reduces the risk of any of these complications from occurring.

Estimate of fees

Typically, costs associated with total knee replacement surgery as a privately insured patient at Midwest orthopaedics include your initial consultation fee, review consultation fee & Dr Singh’s surgical fees. Other related charges include the Anaesthetist, the hospital fees, implants/prosthesis and any in-patient pathology and radiology charges if x-rays or scans were required:

• Initial consultation fee – $76.80 back from Medicare
• Review consultation fee – $38.60 back from Medicare
• Surgical Fees – For privately insured patients, Dr Singh’s fees are typically a proportion of the AMA Fee or a “Known Gap” Fee. Please check with your health fund to ensure you have appropriate cover.
• Anaesthetist’s fees – The Anaesthetist s fees will be given to you by the hospital. Your anaesthetist will contact you prior to surgery and obtain informed financial consent.
• Hospital fees – If you have private health insurance this is confined to your excess, but certain orthopaedic procedures are excluded from some policies and therefore should be checked prior to booking in.
• Pathology and radiology – These are blood tests and imaging taken during your inpatient stay that may also incur added costs.
• Implants and prosthesis – Most of these are covered by your insurance company, but once again it is important to check with your health fund prior to the surgery.

Your level of healthcare and your provider greatly influence your out-of-pocket expenses, so we recommend that you check with your health fund prior to booking in for surgery.

Self-Insured Patients

An increasing number of people without private health insurance are choosing to “Self-Insure” or pay for their own surgery. This is because, even though Dr Singh operates in the public sector at Geraldton Regional Hospital, the waiting list to even meet with him can be long (too long), followed by even longer waiting lists for their operation.

All the private hospital fees associated with your surgery are however an out-of-pocket expense. Our team can assist you in obtaining an estimate of costs before proceeding.