Knee Replacement Surgery

What is Knee Replacement Surgery?

Knee replacement (total knee arthroplasty) is a procedure that resurfaces a knee damaged by arthritis or injury. Metal and plastic components are used to cap the ends of the bones that form the knee joint, along with the kneecap. It is one of the most successful operations in medicine, with the vast majority of patients achieving significant pain relief and improved function.

When is Knee Replacement Recommended?

Knee replacement is typically considered when:

• Severe knee pain or stiffness limits everyday activities including walking, climbing stairs, or getting in and out of chairs
• Moderate or severe knee pain occurs at rest or disturbs sleep
• Knee inflammation and swelling does not improve with rest or medication
• Knee deformity has developed — bowing in or out of the knee
• Non-surgical treatments have not provided sufficient relief

Types of Knee Replacement

Total Knee Replacement

The most common type. The entire joint surface — both the femur (thigh bone) and tibia (shin bone) ends — is resurfaced with metal components, with a plastic spacer between them. The back of the kneecap may also be resurfaced.

Partial (Unicompartmental) Knee Replacement

Only the damaged compartment of the knee is replaced, leaving healthy bone and tissue intact. Recovery tends to be faster, and the knee often feels more natural, but not all patients are suitable candidates.

Kneecap (Patellofemoral) Replacement

Only the kneecap joint is replaced. Suitable only for isolated kneecap arthritis in carefully selected patients.

Robotic-Assisted Knee Replacement

Increasingly available at specialist centres, robotic assistance helps surgeons achieve more precise implant positioning. Some evidence suggests improved short-term outcomes, though long-term data is still emerging.

What Happens During Surgery?

Under general or spinal anaesthetic, the surgeon makes an incision over the knee to expose the joint. Damaged cartilage and a thin layer of bone are removed from the femur, tibia, and usually the patella. Metal components are fixed to these bone surfaces, and a plastic spacer is placed between the metal parts to create a smooth, gliding surface. The procedure takes 1–2 hours.

Risks and Complications

• Blood clots (DVT/PE) — a significant risk with any lower limb surgery; preventable with anticoagulants and compression stockings
• Infection — deep infection requiring further surgery is rare but serious
• Stiffness — some patients develop significant stiffness; physiotherapy is essential to prevent this
• Implant problems — loosening, wear, or instability may require revision surgery over time
• Nerve or blood vessel damage — uncommon but possible
• Ongoing pain — a small number of patients continue to experience pain after knee replacement

Recovery After Knee Replacement

Knee replacement recovery requires active participation. Physiotherapy is critical for a good outcome:

• Hospital stay: Typically 2–4 days
• Walking aids: Crutches or a frame for 4–6 weeks
• Swelling: Expect significant swelling for several months; elevate the leg and apply ice regularly
• Return to driving: Usually 6–8 weeks
• Return to work: 6–12 weeks for sedentary roles; longer for physical work
• Bend in the knee: Goal is usually to reach 90° flexion within 3 months and 110–120° by 6 months
• Full recovery: Up to 12 months for complete improvement

How Long Will a Knee Replacement Last?

Modern knee replacements are highly durable. Studies show that around 90% of knee replacements are still functioning well at 15 years, and 80% at 20 years. Factors affecting longevity include age, weight, activity level, and implant design. Staying at a healthy weight and avoiding high-impact activities helps prolong the life of the implant.

Accessing Knee Replacement in North Wales

Knee replacement surgery in North Wales is provided through Betsi Cadwaladr University Health Board (BCUHB), with services at Ysbyty Gwynedd (Bangor), Wrexham Maelor Hospital, and Glan Clwyd Hospital. Your GP can refer you to an orthopaedic surgeon for assessment.

Private options are also available at independent facilities across North Wales and the wider region, which may offer shorter waiting times and more choice over your surgical team.