Who Is a Candidate for Knee Replacement Surgery?

Who Is a Candidate for Knee Replacement Surgery?

This article explains who qualifies for knee replacement surgery, detailing clinical criteria, age considerations, and when the procedure becomes necessary.

The knee is one of the most complex and weight-bearing joints in the human body. Over time, due to aging, injury, or chronic wear and tear, the cartilage that cushions this joint can deteriorate, leading to pain, stiffness, and reduced mobility. In advanced cases of knee osteoarthritis (gonarthrosis), knee replacement surgery—also known as total knee arthroplasty—becomes a highly effective treatment option.

However, not every person with knee pain is a suitable candidate for knee replacement. The procedure is most beneficial when performed on the right patient at the right time. In this article, we explain the ideal candidate profile, clinical criteria, and evaluation process for knee replacement surgery in detail.

What Is a Knee Replacement?

Knee replacement is a surgical procedure where the damaged cartilage and bone surfaces in the knee joint are removed and replaced with artificial components made of metal and polyethylene. These prosthetic parts restore the smooth movement of the joint, reduce pain, and improve overall function.

There are two main types:

• Total knee replacement (TKR): Both the femur and tibia joint surfaces are replaced.
• Unicompartmental (partial) knee replacement: Only the inner or outer compartment of the knee is replaced—suitable for earlier-stage, localized damage.

Who Is a Good Candidate for Knee Replacement?

1. Patients with Advanced Knee Osteoarthritis

• Radiographic evidence of stage 3 or 4 osteoarthritis
• Complete loss of joint space and visible bone-on-bone contact
• Structural deformities and bone spurs (osteophytes)

Knee replacement provides significant pain relief and functional improvement in these cases.

2. Patients with Severe Daily Life Limitations

• Difficulty walking, climbing stairs, or performing basic activities
• Dependence on assistive devices even inside the home
• Night pain disrupting sleep
• Inability to squat, kneel, or sit comfortably

Knee replacement can dramatically improve quality of life in such individuals.

3. Patients Unresponsive to Conservative Treatments

• Those who have failed to respond to medications, physical therapy, injections (e.g., hyaluronic acid, PRP)
• Lifestyle changes such as weight loss and exercise have not provided relief

When all non-surgical treatments fail, surgery becomes the definitive option.

4. Typically Age 60 or Older (But Not Always)

Knee replacement is commonly performed in individuals over the age of 60. However, biological age is more important than chronological age.

• Patients with good bone quality and realistic expectations
• Younger individuals with debilitating conditions (e.g., rheumatoid arthritis, congenital deformities) may also benefit

Each case must be evaluated individually.

5. Patients with Joint Deformity

• Varus (inward bowing) or valgus (outward bending) deformities
• Poor alignment affecting gait and increasing stress on surrounding joints

Knee replacement helps correct alignment and improves walking mechanics.

Who Is Not a Good Candidate?

• Patients with active joint infection (surgery must be postponed)
• Uncontrolled diabetes, cardiovascular instability, or poor general health
• Early-stage osteoarthritis or tolerable symptoms
• Non-compliant patients with severe neurological or cognitive disorders

In such cases, conservative treatment should be prioritized.

Preoperative Evaluation for Knee Replacement

Before scheduling surgery, a thorough assessment is essential:

• Radiographic evaluation (weight-bearing X-rays)
• Laboratory tests and anesthesia clearance
• Cardiology or internal medicine consultations if needed
• Patient education about surgical expectations and outcomes

A successful knee replacement begins with choosing the right patient and planning the right procedure.