Rand and Ilstrup asked whether implant design, diagnosis, age, fixation, earlier knee surgery and revision status changed how long total knee arthroplasties lasted before revision.
Mayo Clinic Total Joint Registry review of 9200 knee arthroplasties in 5810 patients (1971 to 1987), with revision or removal as the end point.
Key Findings
Four factors independently lowered revision risk: primary surgery, rheumatoid arthritis, age 60 or older and a metal‑backed condylar tibial component. With all four, survival was 97% at 5 and 10 years.
Across all 9200 knees, survival free of revision was 91% at 5 years, 80% at 10 and 69% at 15. At 10 years it was 81% after primary and 72% after revision arthroplasty (p < 0.0001).
Metal‑backed condylar knees had 98% 5‑year survival, vs 88% for older resurfacing, 84% older constrained, 81% newer constrained and 86% unicompartmental designs. Posterior‑stabilized knees (96%) did not differ within primary or revision subsets.
Patients under 60 had 76% survival at 10 years vs 82% for those 60 or older (p < 0.0001). After revision, age had no significant effect.
Primary knees with earlier non‑arthroplasty surgery had lower 10‑year survival, 72% vs 84% (p < 0.0001), but the difference was significant only for older resurfacing and unicompartmental designs. Post‑traumatic knees fared worst, 63% at 10 years in 55 knees.
Five‑year survival was 98% for cemented and 93% for cementless metal‑backed condylar knees (p < 0.02), but cementless patients were younger, and 918 vs 310 knees of one design did not differ. The authors concluded only that cementless fixation was no more durable.
Authors' conclusion
We concluded that the most favorable variables for prolonged survival (no revision) of a total knee arthroplasty are a primary arthroplasty, a diagnosis of rheumatoid arthritis, an age of 60 years or more, and use of a resurfacing condylar prosthesis with a metal-backed tibial component.
Rand and Ilstrup asked whether implant design, diagnosis, age, fixation, earlier knee surgery and revision status changed how long total knee arthroplasties lasted before revision.
Mayo Clinic Total Joint Registry review of 9200 knee arthroplasties in 5810 patients (1971 to 1987), with revision or removal as the end point.
Key Findings
Four factors independently lowered revision risk: primary surgery, rheumatoid arthritis, age 60 or older and a metal‑backed condylar tibial component. With all four, survival was 97% at 5 and 10 years.
Across all 9200 knees, survival free of revision was 91% at 5 years, 80% at 10 and 69% at 15. At 10 years it was 81% after primary and 72% after revision arthroplasty (p < 0.0001).
Metal‑backed condylar knees had 98% 5‑year survival, vs 88% for older resurfacing, 84% older constrained, 81% newer constrained and 86% unicompartmental designs. Posterior‑stabilized knees (96%) did not differ within primary or revision subsets.
Patients under 60 had 76% survival at 10 years vs 82% for those 60 or older (p < 0.0001). After revision, age had no significant effect.
Primary knees with earlier non‑arthroplasty surgery had lower 10‑year survival, 72% vs 84% (p < 0.0001), but the difference was significant only for older resurfacing and unicompartmental designs. Post‑traumatic knees fared worst, 63% at 10 years in 55 knees.
Five‑year survival was 98% for cemented and 93% for cementless metal‑backed condylar knees (p < 0.02), but cementless patients were younger, and 918 vs 310 knees of one design did not differ. The authors concluded only that cementless fixation was no more durable.
Authors' conclusion
We concluded that the most favorable variables for prolonged survival (no revision) of a total knee arthroplasty are a primary arthroplasty, a diagnosis of rheumatoid arthritis, an age of 60 years or more, and use of a resurfacing condylar prosthesis with a metal-backed tibial component.