Fig. 1

PRISMA 2009 flow diagram on selection of articles for effect of age on outcomes of TKA. *244 not in English, 3174 rejected by both initial reviewers for being irrelevant- did not address TKA as primary problem different surgical tech or med tx being compared, not knee, 274 Outcomes not addressed- eg not dvt/mortality/ssi/MI, 212 TKA bilateral or mixed with hip and knee, 1 qualitative study, 12 unavailable articles, review articles. ^49 studies did not separate hip and knee patients, 17 did not look at the outcome of interest, 4 were review articles, 60 did not study the effect of age, 8 did not have a control younger group, and 3 studies did not look at TKA