Total Knee Replacement

Total Knee Replacement Surgery (TKR) 

Total knee replacement, also called total knee arthroplasty, is a surgical procedure in which damaged or worn-out surfaces of the knee joint are removed and replaced with artificial components.  
The aim is to relieve chronic pain, correct deformity, and restore functional movement when conservative treatments no longer provide relief.

When Is Total Knee Replacement Needed

• Persistent knee pain at rest or while walking
• Severe stiffness limiting daily activities
• Progressive knee deformity such as bow legs or knock knees
• Poor response to medicines, physiotherapy, injections, or lifestyle modification

Common Conditions Leading to TKR

• Osteoarthritis, the most common cause
• Rheumatoid arthritis
• Post-traumatic arthritis following injury
• Advanced degenerative joint disease

How Is The Surgery Performed

1. Damaged cartilage and bone surfaces of the knee joint are removed
2. Femur and tibia are shaped to fit the implants
3. Metal components are fixed to the bone
4. A medical-grade plastic spacer is placed between them for smooth movement
5. The kneecap may be resurfaced if required
6. Surgery duration is usually 60 to 120 minutes

Implant Materials Used in Total Knee Replacement

Cobalt–chromium 

Used for its strength, wear resistance, and corrosion resistance

Titanium alloy 

Used for its lightweight nature and excellent bone compatibility

Ultra-high molecular weight polyethylene 

Used as a smooth cushioning spacer between metal parts

All materials are bio-compatible, well tested, and safe for long-term use

Implant Lifespan

Average implant lifespan is 15 to 20 years or more
Longevity depends on age, activity level, body weight, surgical technique, and rehabilitation

Risks, Disadvantages, and Limitations of Total Knee Replacement

1. It is a major surgical procedure requiring anaesthesia and hospital stay
2. Risk of infection, which may require prolonged treatment or further surgery
3. Risk of blood clots in the legs or lungs, especially in early recovery
4. Possible knee stiffness or reduced range of motion
5. A small number of patients may have persistent pain or dissatisfaction
6. The knee may not feel exactly like a natural joint
7. Kneeling may remain uncomfortable
8. High-impact activities such as running and jumping are discouraged
9. Implants have a limited lifespan, usually around 15 to 20 years
10. Revision surgery may be required in the future and is more complex

• Residual pain despite successful surgery

A small group of patients continue to experience pain even when X-rays and implant position are satisfactory. This may be due to soft tissue imbalance, nerve sensitivity, muscle weakness, or altered pain perception. Complete pain elimination cannot be guaranteed in every case.

• Instability or feeling of knee “giving way”

Some patients experience a sense of looseness or instability while walking or changing direction. This can result from ligament imbalance, muscle weakness, or implant positioning and may require prolonged physiotherapy or, rarely, revision surgery.

• Reduced knee flexibility compared to expectations

While knee movement improves after surgery, full bending like a normal knee may not be achieved. Activities requiring deep flexion such as squatting or sitting cross-legged may remain limited, especially in patients with long-standing preoperative stiffness.

• Mechanical noises or awareness of the implant

Clicking, grinding, or awareness of the artificial joint during movement can occur. These sounds are usually harmless but may cause anxiety. The knee may feel mechanical rather than natural during certain activities.

• Bone loss around the implant over time

Gradual bone thinning can occur around the implant due to stress redistribution. This may not cause immediate symptoms but can complicate future revision surgery if needed.

• Allergic or sensitivity reactions to implant materials

Very rarely, patients may develop sensitivity to metal components, leading to pain or swelling without infection. This requires careful evaluation and may influence implant selection in future surgeries.

• Psychological adjustment and expectation mismatch

Some patients struggle emotionally if recovery is slower than expected or if the knee does not feel normal. Unrealistic expectations can lead to dissatisfaction even when surgical outcomes are technically good. Proper counselling before surgery plays a key role in satisfaction.

• Revision Surgery Due to Loosening

Loosening of a knee replacement can occur over time if the implant wears out, the surrounding bone weakens, or rehabilitation and long-term care are inadequate. When loosening becomes symptomatic, a revision total knee replacement may be required, which means removing the old implant and replacing it with a new one.

How Much More Difficult Is Revision Knee Surgery

1. Revision surgery is significantly more complex than the first operation.
2. More bone loss is usually present, making fixation of the new implant harder.
3. Surgery time is longer and requires specialised implants and techniques.
4. Risk of complications such as infection, blood loss, and stiffness is higher.
5. Hospital stay and recovery period are usually longer.
6. Functional outcomes may be slightly inferior compared to the first knee replacement.

Proper care can significantly delay or prevent implant loosening, reducing the need for revision surgery.

Why Is Total Knee Replacement Recommended Despite the Limitations

For severe knee disease, benefits of pain relief and restored function outweigh the risks

• Irreversible Joint Damage

Advanced knee arthritis permanently destroys cartilage and joint alignment. Once this stage is reached, the knee cannot heal or regenerate, and no medicine or injection can reverse the damage.

• Temporary Relief From Non-Surgical Treatments

Pain medicines, injections, and physiotherapy provide only short-term relief. Over time, their effect reduces while side-effects and dependency increase, without restoring normal walking.

• Progressive Loss of Mobility and Strength

As pain increases, patients reduce movement. This leads to muscle wasting, poor balance, weight gain, and higher risk of falls, making recovery more difficult later.

• Impact on Daily Life and Mental Well-Being

Chronic knee pain affects sleep, mood, social life, and independence. Many patients gradually become dependent on others for basic daily activities.

• Delay Makes Surgery and Recovery Harder

Postponing surgery allows deformity, stiffness, bone loss, and ligament weakness to progress. Surgery becomes technically more complex and recovery may be slower with reduced final outcome.

• Addresses the Root Cause, Not Just Symptoms

Total knee replacement removes the damaged joint surfaces and restores alignment. It provides predictable pain relief, improved walking, and correction of deformity.

• Long-Term Quality-of-Life Benefit

Although it involves cost and recovery, total knee replacement is a one-time intervention that provides long-term relief, independence, and improved quality of life for patients with severe disease.

Who Is an Ideal Candidate

• Severe knee arthritis affecting daily life
• Failure of non-surgical treatments
• Realistic expectations about outcomes
• Medically fit for surgery

Why Proper Maintenance Matters

1. Good outcomes after total knee replacement depend on:
2. Regular physiotherapy and lifelong muscle strengthening
3. Maintaining healthy body weight
4. Avoiding high-impact activities
5. Early treatment of infections anywhere in the body
6. Regular orthopaedic follow-up

Recovery and Rehabilitation

1. Hospital stay is usually 2 to 4 days
2. Walking with support begins within 24 to 48 hours
3. Physiotherapy starts early to regain movement and strength
4. Most patients resume routine daily activities within 4 to 6 weeks
5. Full recovery and maximum benefit may take 3 to 6 months
6. Regular exercises and follow-up are essential for long-term success

Key Takeaway

Total knee replacement is not meant to create a perfect knee but to restore function and comfort. 

With proper patient selection and rehabilitation, it provides reliable pain relief, improved mobility, and long-term functional recovery and remains one of the most successful procedures in orthopaedic surgery