From the Guidelines
The average lifespan of a knee replacement is typically 15 to 20 years, though many modern implants can last even longer, with long-term TKA failure rates of <1% per year 1.
Factors Influencing Longevity
Several factors influence the longevity of a knee replacement, including:
- The patient's age, weight, and activity level
- The type of implant used
- Proper surgical technique during the initial procedure
- Following post-operative rehabilitation protocols
Implant Materials and Design
The implant material matters significantly, with most modern knee replacements using metal alloys (typically titanium or cobalt-chromium) for the femoral component and high-density polyethylene for the tibial component, designed to withstand years of stress 1.
Revision Surgery and Complications
Some patients may eventually need revision surgery if the implant wears out or develops complications, such as loosening, infection, or instability, though improvements in materials and surgical techniques continue to extend the functional lifespan of knee replacements 1.
Monitoring and Follow-up
Regular follow-up appointments with orthopedic surgeons are important to monitor implant performance over time and identify potential issues early on, allowing for prompt intervention and minimizing the risk of complications 1.
From the Research
Average Lifespan of a Knee Replacement
The average lifespan of a knee replacement can vary depending on several factors, including the type of replacement, patient age, and overall health.
- According to a systematic review and meta-analysis published in the Lancet in 2019 2, approximately 82% of total knee replacements (TKRs) last 25 years, while about 70% of unicondylar knee replacements (UKRs) last 25 years.
- A study published in Clinical Orthopaedics and Related Research in 2012 found that pain relief and functional improvement can remain 20 years after knee arthroplasty 3.
- Another study published in Acta Orthopaedica in 2010 found that younger age increases the risk of early prosthesis failure following primary total knee replacement for osteoarthritis 4.
- A study published in The Bone & Joint Journal in 2014 analyzed the failure mechanisms of knee replacements and found that aseptic loosening was the predominant mechanism of failure, followed by instability and infection 5.
- A population-based cohort study published in the Lancet in 2017 found that the lifetime risk of requiring revision surgery after total knee replacement increases for younger patients, up to 35% for men in their early 50s 6.
Factors Affecting Knee Replacement Lifespan
Several factors can affect the lifespan of a knee replacement, including:
- Patient age: Younger patients are at a higher risk of early prosthesis failure 4, 6.
- Type of replacement: TKRs and UKRs have different lifespans, with TKRs lasting longer on average 2.
- Overall health: Patients with certain health conditions or comorbidities may be at a higher risk of complications or early failure 5.
- Surgical technique and implant quality: Improvements in implant manufacture and surgical technique can help reduce the risk of early failure 5.