Knee replacement surgery offers a significant improvement in quality of life for many experiencing severe knee pain and mobility issues. While these artificial joints are designed for durability, patients often wonder about their longevity and potential failure. Like any mechanical device, knee replacements are not immune to issues that can compromise their function over time, potentially necessitating further medical intervention.
Understanding Knee Replacement Durability
While highly successful, knee replacements are not designed to last indefinitely. “Breaking” typically refers to issues like implant detachment, excessive plastic wear, or infection, which compromise the implant’s function. Modern knee replacements are robust, with 85% to 90% of implants functioning well for at least 15 to 20 years, and some lasting even longer, up to 25 years or more. The longevity of an implant can vary based on patient factors and advancements in surgical techniques and materials.
Primary Causes of Knee Replacement Failure
Several factors can lead to knee replacement failure, ranging from mechanical issues to biological responses. Aseptic loosening is a common reason, where the implant detaches from the bone without infection. This often occurs due to wear debris generated from the implant surfaces, which can trigger an inflammatory response that leads to bone resorption around the implant, weakening its bond.
Polyethylene wear is another frequent cause of failure, involving the gradual wearing down of the plastic spacer component within the knee replacement. This wear can produce tiny particles that contribute to aseptic loosening and osteolysis, a condition where healthy bone is broken down. Implant infection, known as periprosthetic joint infection (PJI), is a serious complication that can necessitate the removal of the implant. Although relatively uncommon (less than 1-2% of cases), infection is a significant reason for revision surgery.
Fractures can also occur around the implant, known as periprosthetic fractures, often resulting from trauma. These fractures can compromise the implant’s stability and may require complex surgical treatment. Issues with instability or malalignment can also lead to failure, occurring when the knee becomes unstable due to stretched soft tissues or improper positioning of the implant components. This can result in the knee feeling like it will give out. While rare, a literal fracture of the metal or ceramic components of the implant can occur, usually after many years due to material fatigue or extreme stress.
Identifying Potential Problems
Recognizing the signs and symptoms of a failing knee replacement is important for seeking timely medical attention. Any sudden change in the knee’s function or the development of these symptoms warrants an immediate consultation with an orthopedic surgeon for evaluation. Common indicators include:
- Persistent or new pain, especially if it worsens with activity or at rest.
- Swelling, redness, or warmth around the knee joint, potentially signaling an infection.
- Stiffness, which can limit the knee’s range of motion.
- Instability, where the knee feels like it might buckle or give out.
- Clicking or grinding noises from the joint.
Strategies for Long-Term Success
Maximizing the longevity of a knee replacement involves diligent post-operative care and certain lifestyle adjustments. Key strategies include:
- Adhering to the prescribed rehabilitation protocol, including regular physical therapy to regain strength and mobility.
- Consistent follow-up appointments with the surgeon to monitor the implant’s condition and address any potential issues early.
- Maintaining a healthy weight, as excessive body weight places increased stress on the implant, accelerating wear.
- Avoiding high-impact activities like running or jumping; instead, engage in low-impact exercises such as walking, swimming, or cycling to maintain joint flexibility and muscle strength.
- Preventing infection by practicing good hygiene and promptly treating any infections elsewhere in the body. Prophylactic antibiotics may be recommended for certain medical procedures to minimize the risk of bacteria spreading to the joint.
If a knee replacement does eventually fail, revision surgery is often an option to replace the problematic components. Revision procedures are typically more complex and may have a longer recovery period than the initial surgery.