Younger age increases the risk of early prosthesis failure following primary total knee replacement for osteoarthritis

Abstract

Background and purpose: Total knee replacements (TKRs) are being increasingly performed in patients aged 65 years who often have high physical demands. We investigated the relation between age of the patient and prosthesis survival following primary TKR using nationwide data collected from the Finnish Arthroplasty Register. Materials: From Jan 1, 1997 through Dec 31, 2003, 32,019 TKRs for primary or secondary osteoarthritis were reported to the Finnish Arthroplasty Register. The TKRs were followed until the end of 2004. During the follow-up, 909 TKRs were revised, 205 (23%) due to infection and 704 for other reasons. Results: Crude overall implant survival improved with increasing age between the ages of 40 and 80. The 5-year survival rates were 92% and 95% in patients aged 55 and 5665 years, respectively, compared to 97% in patients who were > 65 years of age (p 65 years remained after adjustment for these factors (p < 0.001). Interpretation: Young age impairs the prognosis of TKR and is associated with increased revision rates for non-infectious reasons. Diagnosis, sex, type of TKR, use of patellar component, and fixation method partly explain the differences, but the effects of physical activity, patient demands, and obesity on implant survival in younger patients warrant further research.