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Five Reasons Why Knee Replacements Fail

New York City—July 12, 2010

While most knee replacements will function well for years, patients should be aware of the signs of failure—including increased pain or decreased function—that may require a corrective procedure known as revision total knee replacement, if necessary.

"A failed knee implant is usually caused by wear and tear with subsequent loosening of the implant. Other causes are infection, instability, fracture, or stiffness," says Dr. Amar Ranawat, a hip and knee specialist in the Adult Reconstruction and Joint Replacement Division of Hospital for Special Surgery in New York City.

Each year, more than 300 patients elect to receive revision knee surgery at Hospital for Special Surgery, despite the fact that their original surgery was performed elsewhere.

The most common symptoms of a failed knee implant are pain, instability, swelling and stiffness across the entire knee (generalized) or in a small section (localized).

Although knee replacements normally perform well for at least 15-20 years in more than 95 percent of patients, Dr. Ranawat says there are five primary reasons why a knee implant fails:

  • Wear and loosening: Friction caused by joint surfaces rubbing against each other wears away the surface of the implant causing bone loss and loosening of the implants.
  • Infection: Large metal and plastic implants can serve as a surface onto which bacteria can latch.
  • Fracture: Fractures around the knee implant that disrupt its stability may require revision surgery.
  • Instability: A sensation of the knee "giving away" may mean that the soft-tissue surrounding the knee is too weak to support standing and walking. Improperly placed implants may also cause instability.
  • Stiffness: Loss of range of motion which causes pain and a functional deficit.

Revision total knee replacement is a complex procedure that requires extensive pre-operative planning, specialized implants and tools, prolonged operating times and mastery of difficult surgical techniques. It usually takes longer to perform than the original knee replacement, says Dr. Ranawat, and is composed of the following stages:

  • Pre-surgery: Preparation includes X-rays, laboratory tests, knee aspiration and in some cases additional assessments, such as bone scans, CT scans or magnetic resonance imaging (MRI).
  • Surgery: The implant is removed and bone grafts may be used to fill larger areas of bone loss. In some cases, metal wedges, wires or screws may be used to strengthen the bone. Finally, specialized revision knee implants are inserted.
  • Post-operative care: This is very similar to the care of the original knee replacement. Dr. Ranawat's prescription includes a combination of physical therapy, blood management and pain medication. A brace or splint may be used to protect the joint after the surgery.

Dr. Ranawat says that more than 80 percent of patients who undergo revision knee surgery can expect to have good to excellent results. However, he cautions that complete function is not restored for all patients and “up to 20 percent of patients may still experience pain following surgery for months or even years."

With the right tools at hand, revision total knee replacements can deliver the best outcomes possible. A center devoted to bone, joint, muscle and tendon conditions, like Hospital for Special Surgery, has the surgical expertise and resources necessary to deliver the best prognoses and to promise the best outcomes possible for this complex—but necessary—procedure.

Hospital for Special Surgery performs more knee replacements and more hip surgeries than any other hospital in the nation. Visit our Revision Total Knee Replacement page for more information.


About HSS | Hospital for Special Surgery
HSS is the world’s leading academic medical center focused on musculoskeletal health. At its core is Hospital for Special Surgery, nationally ranked No. 1 in orthopedics (for the eighth consecutive year) and No. 3 in rheumatology by U.S. News & World Report (2017-2018). Founded in 1863, the Hospital has one of the lowest infection rates in the country and was the first in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center four consecutive times. The global standard total knee replacement was developed at HSS in 1969. An affiliate of Weill Cornell Medical College, HSS has a main campus in New York City and facilities in New Jersey, Connecticut and in the Long Island and Westchester County regions of New York State. In 2017 HSS provided care to 135,000 patients and performed more than 32,000 surgical procedures. People from all 50 U.S. states and 80 countries travelled to receive care at HSS. In addition to patient care, HSS leads the field in research, innovation and education. The HSS Research Institute comprises 20 laboratories and 300 staff members focused on leading the advancement of musculoskeletal health through prevention of degeneration, tissue repair and tissue regeneration. The HSS Global Innovation Institute was formed in 2016 to realize the potential of new drugs, therapeutics and devices. The culture of innovation is accelerating at HSS as 130 new idea submissions were made to the Global Innovation Institute in 2017 (almost 3x the submissions in 2015). The HSS Education Institute is the world’s leading provider of education on the topic on musculoskeletal health, with its online learning platform offering more than 600 courses to more than 21,000 medical professional members worldwide. Through HSS Global Ventures, the institution is collaborating with medical centers and other organizations to advance the quality and value of musculoskeletal care and to make world-class HSS care more widely accessible nationally and internationally.


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