Survivorship of cemented knee replacements

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Medical Device Analysis

Background:

• Total knee arthroplasty (TKA) is a common procedure for knee osteoarthritis.
• Assessing long-term implant survival is crucial for patient outcomes and healthcare economics.
• Different TKA designs may have varying failure rates and survivorship.

Purpose of the Study:

• To compare the failure rates and overall success of three cemented primary total knee arthroplasty designs.
• To evaluate the 15-year survivorship of these prostheses.
• To identify factors influencing TKA survival.

Main Methods:

• Survivorship analysis of 1,430 cemented primary TKAs performed over 15 years.
• Comparison of three prosthesis types: Total Condylar (polyethylene tibia), Posterior Stabilized (all-polyethylene tibia), and Posterior Stabilized (metal-backed tibia).
• Data collected on implant failures and revision surgeries.

Main Results:

• The Posterior Stabilized prosthesis with a metal-backed tibial component demonstrated the lowest average annual failure rate (0.19%) and a 7-year success rate of 98.75%.
• The Posterior Stabilized prosthesis with an all-polyethylene tibia had a 10-year success rate of 97.34% (0.27% annual failure rate).
• The Total Condylar prosthesis showed a 15-year success rate of 90.56% (0.65% annual failure rate); no metal-backed tibial components required revision for loosening.

Conclusions:

• Posterior stabilized knee prostheses, particularly those with metal-backed tibial components, exhibit superior long-term survivorship compared to older designs.
• Implant survival was not significantly affected by patient demographics such as sex, age, diagnosis, or body weight.
• Infection is identified as a likely predominant cause of failure in cemented primary total knee arthroplasties.