Knee replacement surgery, or knee arthroplasty, is a procedure to replace a damaged or worn-out knee joint with an artificial implant (prosthesis). It is typically recommended for patients with severe arthritis or injury who continue to experience pain and limited mobility despite medications, physiotherapy, or lifestyle changes.

Common causes include osteoarthritis, rheumatoid arthritis, or trauma, which gradually wear down the joint cartilage, leading to stiffness and chronic pain. In the surgery, the damaged joint surfaces are replaced with metal, plastic, or ceramic components designed to restore natural knee movement.

Depending on the extent of damage, patients may undergo a total or partial knee replacement. Most patients experience significant pain relief, better mobility, and improved quality of life after recovery.