Knee Replacement

Overview

Knee replacement surgery (also called knee arthroplasty) is a procedure to replace a damaged knee joint with artificial components. It’s recommended for people with severe knee arthritis or joint damage that hasn’t improved with other treatments like medication, physical therapy, or injections. Your surgeon will remove the damaged bone and cartilage and position new metal and plastic implants to restore function and reduce pain.

Total knee replacement replaces the entire joint, while partial (unicompartmental) knee replacement replaces only the damaged compartment. Our surgeons use advanced imaging and surgical planning techniques, including 3D modelling and robotic-assisted surgery, to customise each procedure to your unique knee anatomy.

The aim of knee replacement is to restore your ability to walk, climb stairs, and enjoy daily activities with less pain and improved stability.

When Is It Needed?

Knee replacement is typically recommended when non-surgical treatments have not provided adequate relief. Common indications include:

• Severe osteoarthritis causing persistent pain and reduced function
• Rheumatoid arthritis or other inflammatory joint diseases
• Post-traumatic arthritis following a significant knee injury
• Severe knee deformities such as bowlegs or knock-knees
• Failure of previous knee surgery or implant loosening

Your surgeon will assess your symptoms, medical history, and imaging studies to determine if replacement is appropriate for you. Typical symptoms suggesting you may benefit from surgery include persistent knee pain (even at rest), significant swelling, reduced range of motion, difficulty walking or climbing stairs, a sensation of instability, and knee locking or catching.

The Procedure

Your surgeon will discuss the surgical approach most suitable for your anatomy and condition. Pre-operative planning involves imaging studies including standing X-rays, MRI, and sometimes EOS scans (which assess full-body alignment). Advanced 3D modelling software allows your surgeon to visualize your knee and plan precise implant positioning.

During surgery, your anaesthetist will administer general or spinal anaesthesia. An incision is made over the knee to expose the joint. Your surgeon carefully removes the damaged cartilage and bone from the ends of the femur (thighbone) and tibia (shinbone). Specialized guides ensure accurate bone cuts aligned with your natural knee anatomy. Test components are inserted to confirm proper fit and alignment. Once confirmed, the definitive metal and plastic implants are permanently secured. Your surgeon pays careful attention to balancing the ligaments and joint surfaces to restore natural knee movement. The incision is closed with sutures or staples and covered with a sterile dressing.

Some surgeons use robotic-assisted technology, such as the Zimmer ROSA system, to enhance the precision of bone cuts and implant positioning. This technology provides real-time data and verification during surgery, allowing customization based on your individual anatomy.

Recovery & Rehabilitation

Hospital stay is typically 2-3 days, though some patients return home sooner. Pain and swelling are normal in the first weeks. You will be prescribed pain-relief medications and may be given blood-thinning medication to reduce the risk of clots.

Early movement is crucial. Physiotherapists will guide gentle exercises starting within hours of surgery. Most patients begin walking with support (walker or crutches) within 1-2 days. You may need walking aids for 4-6 weeks.

Home-based physiotherapy is common and helps build strength and restore range of motion. Your knee should bend to about 90 degrees by week 6, progressing to 110-115 degrees over 3-6 months. Full recovery typically takes 3-6 months, though gradual improvement continues for up to a year.

Wound care is important: keep the incision clean and dry, and attend scheduled follow-up appointments for wound checks (usually at 1-2 weeks) and suture removal. Follow-up X-rays are taken at 6 weeks and 3 months to confirm healing.

Most people return to normal activities (walking, light tasks, swimming) within 2-3 months. Return to more demanding activities is gradual and guided by your surgeon and physiotherapist.

Risks & Complications

As with any surgery, knee replacement carries risks. These are generally uncommon but can include:

• Infection (superficial or deep) — treated with antibiotics or additional surgery if needed
• Blood clot formation in the leg (DVT) — managed with medication and compression
• Excessive bleeding or need for transfusion
• Nerve or blood vessel damage causing numbness or weakness
• Implant loosening or wear over time
• Persistent pain or stiffness despite surgery
• Reactions to implant materials (rare)
• Ongoing swelling

Your surgeon will discuss your individual risk factors and how to minimize complications. Staying well-hydrated, moving early, and following physiotherapy instructions all reduce risk.

Current research shows that modern knee replacements typically last 15-25 years, though implant durability varies by individual factors and activity level.

Frequently Asked Questions

How long do knee replacements last?

Studies suggest most modern knee replacements function well for 15-25 years. Some last longer; some may require revision if wear or loosening occurs. Factors affecting longevity include your weight, activity level, surgeon technique, and implant design.

Can I return to sports after knee replacement?

You can return to low-impact activities (walking, swimming, cycling, golf) within 3-6 months. High-impact sports (running, jumping, pivoting) are typically not recommended, as they accelerate implant wear. Your surgeon will advise based on your individual condition.

Will I set off metal detectors?

The metal implants may trigger security detectors at airports or buildings. You may be given a knee replacement card to carry. Inform security staff of your implant, and they can conduct a pat-down search if needed.

What if I need an MRI?

Most modern knee implants are MRI-safe, though some components may create artifacts. Always inform your doctor about your knee replacement before MRI, and ensure the facility confirms safety with your specific implant model.

Is there pain after surgery?

Yes, post-operative pain is normal and typically peaks in the first 1-2 weeks, then gradually decreases. Your surgical team will manage pain with medications, ice, elevation, and early movement. Pain that persists beyond expected timeframes should be discussed with your surgeon.