Total knee replacement is the definitive treatment for end-stage knee arthritis. Dr Chien-Wen Liew performs all knee replacements using kinematic alignment - a technique that positions the implant to match each patient's unique anatomy rather than a standardised target. Combined with patient-specific planning and disposable instruments, every surgery is prepared and executed with precision.
What Is a Total Knee Replacement?
The knee is a complex joint involving the femur (thighbone), tibia (shinbone), and patella (kneecap). In knee arthritis, the cartilage covering these surfaces gradually wears away, causing bone-on-bone contact that produces pain, stiffness, swelling, and progressive loss of function.
Total knee replacement resurfaces all three compartments of the knee joint with precision-engineered metal and polyethylene components. The diseased cartilage and bone are removed and replaced with an implant designed to replicate the smooth, pain-free movement of a healthy knee.
When performed correctly - with components well-matched to the patient's anatomy and correctly positioned - knee replacement is one of the most transformative procedures in orthopaedic surgery.
Who Needs a Knee Replacement?
Knee replacement is considered when arthritis has progressed to the point where quality of life is significantly affected and non-surgical measures are no longer providing relief. Indicators that surgery may be appropriate include:
- Persistent knee pain that limits walking, climbing stairs, or daily activities
- Pain at rest or at night that disrupts sleep
- Stiffness and swelling that does not settle with rest or anti-inflammatories
- Deformity of the knee - bow-legged or knock-kneed appearance
- Failure of non-surgical treatment including physiotherapy, weight management, and injections
- X-ray evidence of significant joint space loss consistent with symptoms
On imaging, knee arthritis is graded on the Kellgren-Lawrence scale from 1 to 4. Grades 3 and 4 - significant joint-space narrowing and established structural change - are usually where surgical discussion becomes appropriate, provided the symptoms match. There is no mandatory threshold; the decision is always made individually.
The decision is based on symptoms and the impact on your life - not on age or X-ray findings alone. Surgery is considered only once non-operative ways to manage knee arthritis have been explored. Dr Liew assesses each patient individually, taking into account their overall health, activity goals, and expectations - and is transparent about the cost of joint replacement from the outset.
Dr Liew's Approach - Kinematic Alignment
Traditional knee replacement uses a standardised "mechanical alignment" that targets the same fixed angles for every patient. Kinematic alignment takes a different approach - the implant is positioned to restore each patient's specific pre-arthritic anatomy, respecting the individual joint line and ligament tensions that are unique to that person.
"No two patients are alike. The goal of kinematic alignment is to give each patient a knee that feels like their own - not a standardised result."
Dr Chien-Wen Liew, FRACSThis is combined with patient-specific cutting guides - designed from a CT scan of the patient's own anatomy - and single-use disposable instruments that reduce infection risk and improve cutting precision. Dr Liew also uses a lateral curved incision that improves the ability to kneel post-surgery and produces a less visible scar.
Because the alignment is matched to your own anatomy rather than a population standard, the surrounding ligaments are already in balance - so the soft-tissue releases required by traditional mechanical alignment are generally avoided. Patients frequently describe a kinematically aligned knee as feeling closer to their original knee than they expected.
Kinematic vs Mechanical Alignment
| Feature | Kinematic Alignment | Mechanical Alignment |
|---|---|---|
| Alignment reference | Your own anatomy | Population standard (0° axis) |
| Ligament releases | Generally not required | Often required |
| Soft-tissue balancing | Provided by your anatomy | Manual, during surgery |
| Pre-arthritic anatomy | Restored | Corrected to neutral |
| Planning | Patient-specific 3D CT | Standard templating |
| Long-term survivorship | Equivalent in published data | Established benchmark |
Implant Specifications
| Femoral & tibial components | Cobalt-chromium |
| Bearing insert | Cross-linked polyethylene |
| Design | Medial pivot |
| Fixation | Cemented (Palacos with antibiotics) |
| Instruments | Disposable, patient-specific |
| Registry | AOANJRR-listed |
Implant size, position and the final kinematic target are all determined from a CT scan around 6-8 weeks before surgery, then translated precisely to the bone with patient-specific cutting guides. Read more about patient-specific technology and single-use instrumentation.
What Happens During Knee Replacement Surgery
Total knee replacement removes the worn surfaces of the femur, tibia and - in most cases - the patella, replacing them with precision-engineered components. The operation is performed under spinal anaesthesia in most cases, combined with an adductor canal nerve block and a small amount of local anaesthetic at the back of the knee. This gives excellent post-operative pain control and allows early mobilisation. The procedure typically takes 60 to 90 minutes.
Pre-operative planning - A CT scan taken 6-8 weeks earlier is used to build a 3D model of your knee. Implant size, position and the kinematic target are set before surgery, and custom cutting guides are manufactured for you.
Bone preparation - The patient-specific cutting guides are placed on the bone surfaces, directing each cut to match the pre-operative plan exactly.
Implant placement - Cobalt-chromium femoral and tibial components are cemented into position with a cross-linked polyethylene insert, and alignment and stability are confirmed.
Same-day mobilisation - Physiotherapy begins the same day; most patients stand and walk with a frame within hours of a morning procedure.
What to Expect - From Consultation to Recovery
Initial consultation - Dr Liew reviews your imaging, symptoms, and goals. If knee replacement is appropriate, pre-operative planning is arranged including a CT scan for patient-specific guide fabrication.
Surgery day - The procedure takes approximately 60-90 minutes under spinal or general anaesthesia. Most patients walk with a frame on the day of surgery or the morning after.
Hospital stay - Most patients spend 2-3 nights at Eastwood Private Hospital before discharge.
Early recovery (weeks 1-6) - Physiotherapy begins immediately. Return to driving in automatic vehicles is typically at 2-3 weeks. Swelling and stiffness gradually improve over this period.
Full recovery (3-12 months) - Most patients reach a functional plateau between 3 and 12 months, with continued improvement possible beyond that. Low-impact activities such as walking, cycling, and swimming are well-supported. Running and high-impact activities are discussed individually.
Long-term outlook - Modern knee replacements are durable. According to the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), around 92% of total knee replacements are still in place at 20 years - and more than 95% at 15 years. You can read more about what the registry data shows about knee replacement longevity, and use the Oxford Knee Score self-assessment to gauge how your knee is currently affecting you.
Frequently Asked Questions
Request a Consultation
A GP referral is required. Contact Orthopaedics 360 to arrange your appointment at Eastwood Private Hospital.