Total Knee Replacement Surgery

What is a Total Knee Replacement?

Total knee replacement is one of the most commonly performed and successful operations in orthopaedic surgery. It involves removing the damaged surfaces of the knee joint and replacing them with prosthetic components, restoring a smooth, functioning joint in place of one worn down by arthritis or injury.

The knee is the largest joint in the body. It is formed by the lower end of the femur (thigh bone), the upper end of the tibia (shin bone), and the patella (kneecap). These surfaces are covered by articular cartilage, which allows smooth, pain-free movement. When this cartilage wears away, bone-on-bone contact causes pain, stiffness, swelling, and progressive loss of function.

During the procedure, the damaged bone and cartilage are removed from the femur, tibia, and in most cases the undersurface of the patella. These surfaces are then resurfaced with metal components on the femur and tibia, with a high-grade polyethylene (plastic) spacer between them that acts as the new cartilage. The result is a smooth, stable joint that moves without the pain of bone-on-bone contact.

Who Needs a Total Knee Replacement?

The most common reason for total knee replacement is osteoarthritis, where progressive cartilage loss leads to pain, stiffness, and deformity that worsens over time. It is also used to treat:

• Rheumatoid arthritis
• Post-traumatic arthritis following fractures or ligament injuries
• Other conditions causing significant joint destruction

Surgery is generally recommended when knee pain is substantially affecting daily activities — walking, climbing stairs, getting in and out of a car — and when conservative treatments including physiotherapy, anti-inflammatory medications, weight management, activity modification, and injections have failed to provide adequate relief. The decision is based on the degree of symptoms, the extent of joint damage on imaging, and the patient’s overall health and goals rather than age alone.

Surgical Technique

Dr Slattery often uses a lateral incision for total knee replacement. Unlike the traditional midline incision, this approach preserves the nerves at the front of the knee, which reduces the risk of numbness after surgery and allows most patients to kneel comfortably on their replacement. The incision also heals with a less prominent scar.

Surgery is performed under spinal or general anaesthesia and typically takes one to two hours. Dr Slattery is experienced in the use of robotic-assisted knee replacement, where a detailed three-dimensional map of the knee is generated during the procedure. A robotic arm then assists with making highly precise bone cuts and positioning the implants accurately. This technology supports optimal alignment and may contribute to long-term implant performance. Not all patients require robotic assistance, and the most appropriate technique will be discussed with you at your consultation.

Implant Selection

Dr Slattery uses a range of knee implants and selects the most appropriate for each patient based on their anatomy, degree of deformity, bone quality, and activity level. Implants may be cemented or uncemented, and the polyethylene spacer may be fixed or mobile-bearing depending on the clinical situation.

What to Expect After Surgery

It is common to notice some clicking or mild sounds from the metal and plastic components when bending or walking — this is a normal feature of knee replacements and not a cause for concern. Most patients find these sensations diminish over time.

Knee replacement reliably reduces pain and improves the ability to perform daily activities. Realistic activities following total knee replacement include:

• Walking
• Swimming
• Cycling
• Golf
• Driving
• Light hiking and other low-impact pursuits

Higher-impact activities such as running are generally not recommended, as they accelerate implant wear. Your surgeon will discuss appropriate activity levels based on your individual circumstances.

Recovery

Most patients are up and walking with crutches on the day of surgery or the morning after, with the guidance of the physiotherapy team. Some discomfort in the first one to two weeks is normal and expected as the tissues heal.

The wound is typically reviewed at two weeks. By four to six weeks, most patients are walking comfortably without crutches. By twelve weeks, the majority have made significant progress and are managing everyday activities well. The following reflects Dr Slattery’s typical recovery guidance, though your treating team will tailor this to your individual progress:

• From ~2 weeks: exercise bike
• From ~4 weeks: hydrotherapy
• Up to 12 months: strength, range of motion and endurance continue to improve

Achieving good range of motion after knee replacement requires consistent effort with rehabilitation exercises in the early weeks. Moving the knee regularly and managing pain adequately to allow this movement is an important part of recovery. Your physiotherapy team will guide you through this process.

Return to office-based work is typically possible within two to four weeks. Physically demanding work may require six or more weeks away. Driving depends on which leg was operated on, vehicle type, and whether you have adequate strength and response time — your surgeon will advise you specifically on this.

Risks and Complications

Total knee replacement is a safe and well-established procedure, but as with any major surgery it carries risks. These include:

• Infection
• Blood clots (deep vein thrombosis or pulmonary embolism)
• Bleeding
• Stiffness
• Ongoing pain
• Implant loosening or wear over time
• Fracture
• Injury to adjacent nerves or blood vessels

Some patients experience numbness at the side of the knee due to small sensory nerve branches in the area — this typically improves over six to twelve months.

Stiffness is one of the more common challenges following knee replacement. Early and consistent physiotherapy is important in minimising this risk. In a small number of cases, further surgery may be required to address persistent stiffness.

Dr Slattery takes a thorough approach to minimising risk, and all relevant risks will be discussed in detail at your consultation.

How Long Will a Knee Replacement Last?

Modern knee replacement implants are highly durable. Joint replacement registry data shows that the majority of knee replacements are still functioning well at fifteen to twenty years, though longevity varies depending on patient age, activity level, body weight, bone quality, and implant type. Revision surgery — replacing a worn or failing implant — is generally more complex than the original procedure, which is why appropriate implant selection at the primary operation is important.

Frequently Asked Questions

How long will my recovery take?

Most patients notice significant improvement by six to twelve weeks. Full recovery — including strength, walking endurance, and return to recreational activities — typically takes three to six months, with ongoing improvement possible for up to twelve months. Recovery varies between individuals depending on overall health, preoperative fitness, and engagement with rehabilitation.

Will I be able to kneel after a knee replacement?

Where Dr Slattery uses a lateral incision, this preserves the nerves at the front of the knee, meaning most patients are able to kneel after their knee replacement. Kneeling may feel different or mildly uncomfortable for some patients, but it is not harmful to the joint.

Is the clicking I hear from my knee normal?

Yes. It is common to feel or hear some clicking or soft sounds from the metal and plastic components, particularly when bending the knee or walking. This is a normal feature of knee replacements and is not a sign of a problem. Most patients find it diminishes over time.

How much does a total knee replacement cost?

For patients with appropriate private health insurance, the majority of the cost is covered by the insurer. Out-of-pocket costs vary depending on your level of cover, the implants used, and the length of your hospital stay. It is worth confirming your policy covers joint replacement surgery, as this is often excluded on lower levels of cover. Dr Slattery’s rooms can provide a detailed cost estimate prior to surgery.

Medical Disclaimer
The information on this page is intended as general patient education and does not constitute medical advice. Every patient is different, and treatment decisions should always be made in consultation with a qualified medical professional based on your individual circumstances, health history, and imaging. Outcomes from surgery vary between patients and cannot be guaranteed. If you have concerns about your knee health or are considering surgery, please contact Dr Slattery’s rooms to arrange a consultation.