Why Knee Replacements Fail

Knee replacements are designed to replace damaged or worn-out knee joints with artificial parts that restore movement and eliminate pain. Although knee replacements are designed to be tough and durable, they do sometimes fail. What follows is a brief list of the most common reasons why they don't last forever.

Loosening

• Loosening of the knee prosthesis is a major reason why knee replacements fail. As it becomes loose, the prosthesis loses its ability to function properly and causes pain as the condition worsens.

Wear

• Although knee replacements are designed to last for many years, they do eventually wear out and require revisionary knee replacement surgery, which replaces the worn-out prosthesis with a new one.

Osteolysis

• Osteolysis is a condition in which the bone surrounding a knee replacement prosthesis becomes soft and spongy and begins to wear away, which causes it to become unstable and eventually fail.

Injury

• Some times the replacement fails because of injury to the prosthesis itself. Any type of blunt force trauma to the knee, especially one that causes fracture of the prosthesis, can cause a knee replacement to break down.

Misuse

• Although artificial knee replacements are designed to be very durable and long-lasting, there are certain types of activities that should be avoided. High-impact, high-stress exercises such as running, jumping and contact sports can increase the speed of a knee replacement's deterioration and lead to early failure of the prosthesis.