This 1997 Insall series is a landmark survivorship analysis of 2,629 cemented primary TKAs performed over 22 years at HSS. It compares five implant designs using Kaplan-Meier actuarial methods, reporting both best-case and worst-case scenarios. The central question: which design lasts longest, and what actually causes failure?
The benchmark numbers in this paper are ones every trainee should know before counseling a TKA patient: a well-designed cemented implant with a metal-backed tibial component achieves greater than 98% survivorship at 14 years. That figure is why cemented fixation remains the standard against which cementless designs are measured.
The shift from all-polyethylene to metal-backed tibial components — introduced at HSS in 1981. Cut the annual failure rate from 0.46% to 0.14%. That difference compounds over decades of implant life and explains why metal backing became universal.
The finding that infection, not loosening, accounts for 56% of all failures reframes where the unsolved problem lies. The implant engineering challenge has largely been met; the remaining clinical challenge is preventing and managing periprosthetic joint infection.
The survivorship equivalence across age, weight, and diagnosis is directly actionable: age or rheumatoid disease alone should not be a contraindication to TKA, and this paper is part of the evidence base supporting that position.
This 1997 Insall series is a landmark survivorship analysis of 2,629 cemented primary TKAs performed over 22 years at HSS. It compares five implant designs using Kaplan-Meier actuarial methods, reporting both best-case and worst-case scenarios. The central question: which design lasts longest, and what actually causes failure?
The benchmark numbers in this paper are ones every trainee should know before counseling a TKA patient: a well-designed cemented implant with a metal-backed tibial component achieves greater than 98% survivorship at 14 years. That figure is why cemented fixation remains the standard against which cementless designs are measured.
The shift from all-polyethylene to metal-backed tibial components — introduced at HSS in 1981. Cut the annual failure rate from 0.46% to 0.14%. That difference compounds over decades of implant life and explains why metal backing became universal.
The finding that infection, not loosening, accounts for 56% of all failures reframes where the unsolved problem lies. The implant engineering challenge has largely been met; the remaining clinical challenge is preventing and managing periprosthetic joint infection.
The survivorship equivalence across age, weight, and diagnosis is directly actionable: age or rheumatoid disease alone should not be a contraindication to TKA, and this paper is part of the evidence base supporting that position.