Common Symptoms of a Failed Knee Replacement

man having knee examined by doctorThe majority of patients who undergo knee replacement surgery experience successful outcomes, with long-lasting improvements in pain, mobility, and knee function. However, complications following knee replacement can occasionally arise for various reasons, resulting in what is commonly referred to as a “failed knee replacement”. When a knee replacement fails – whether it’s shortly after surgery, or many years later – it may require a revision, or “re-do”, knee replacement surgery.

In this blog, I’ll address the common reasons why a knee replacement may fail and the signs and symptoms that may suggest complications following knee replacement surgery.

What causes a failed knee replacement?

A knee replacement can fail for a variety of reasons, including the following:

  • Implant loosening and wear – An implant needs to be securely attached to the bone, but over time, it can loosen and cause pain. This can occur because of high-impact activities, wear and tear on the parts, or deterioration of the bone around the implant. Sometimes the bond between the cement and implant will fail (i.e., debonding).
  • Infection – Infection can occur after any surgery, including a knee replacement. It can happen shortly after your surgery or, in some cases, years later. Infections of total joint implants are called “peri-prosthetic joint infections” or “PJI”.
  • Instability – An implant works with the existing ligaments around the knee, so if these ligaments are damaged, your knee replacement can become unstable. Other times, there is a mismatch between the soft tissue tensioning when the knee is in extension (i.e., fully straight) and when the knee is flexed (i.e., bent).
  • Scar tissue – Scar tissue can build up around the knee joint, causing stiffness and a limited range of motion. This is called “arthrofibrosis”.
  • Fractures – A bone may break around a knee replacement, which is often caused by a fall or other trauma. Fractures around implants are called “peri-prosthetic fractures”.
  • Poor alignment – Knee replacements must be properly aligned in all three dimensions. Infrequently, components are placed in poor alignment at the time of the initial surgery. This malalignment can cause pain, instability, and poor function of the knee.

It is important to acknowledge that up to 10% of total knee patients may have residual pain that cannot be explained through routine or advanced diagnostic tests. Often the pain is mild in severity and should be treated without surgery. Very rare, and somewhat controversial causes for pain, can include: allergy to implant materials and cement; and complex regional pain syndrome.

What are the symptoms of a failed knee replacement?

Symptoms of a failed knee replacement may include:

  • Pain, which can occur during activity or at rest
  • Swelling around the joint, or recurrent joint effusions
  • Feeling as though your knee wants to “give out” when you’re standing, walking, or going up and down stairs
  • Noticeable warmth in the joint, long after your surgery was completed
  • Painful popping or scratching noises
  • A reduced range of motion and function
  • Inability to place weight on the leg

If you are experiencing any of these symptoms or other symptoms that cause concern, it is important to get evaluated by your surgeon.

How is a failed knee replacement treated?

When a knee replacement fails, I’ll provide conservative non-surgical treatment options whenever possible. The following treatments may be used to help alleviate your symptoms:

  • Rest
  • Activity modification
  • Physical therapy
  • Bracing the knee for additional support
  • Using non-steroidal anti-inflammatory medications (NSAIDs)

Residual pain after total knee replacement without a clear cause can be expected to decrease for up to 5 years after surgery. Therefore, non-surgical management is the treatment of choice when there is no clear diagnosis for residual pain.

When the pain is moderate to severe in quality and there is a clear diagnosis for implant failure, revision joint replacement surgery can help alleviate pain and restore knee function. During the revision surgery, one or more of the previously implanted prosthetic knee components are removed and replaced. The remaining bone may be strengthened with bone grafts, metal augments, and/or bone cement, and new components will be fixed around the joint.

For the vast majority of patients, revision knee replacement surgery has good long-term results, and it provides relief from pain and stiffness while increasing stability and function. However, revision surgery can have an increased risk for complications, and it may not last as long as a primary knee replacement.

If an infection is present, surgery is almost always required. I may need to complete the revision in two stages – one to remove the joint and give the infection time to heal, and one to replace the joint. This is called a “two-stage exchange arthroplasty”. A single stage exchange for infection, during which the infected implant is removed and the final revision is placed during the same surgery, is a possibility. We are currently investigating which approach is superior in terms of (1) eradicating infection and (2) providing the most clinical benefit to patients. If you have an infection and are interested in participating in this trial, please review the trial information on

If you have symptoms of a failed knee replacement, such as pain or instability, make an appointment today for a consultation at my New York City or Stamford office. I’ll conduct any necessary exams and tests, and take into account your overall health, the reason for revision surgery, and other factors to make the best recommendation for your needs.

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