Fig. 1From: Increasing comorbidity is associated with worsening physical function and pain after primary total knee arthroplastyPost-operative interval was 6–12 months post-index TKA and subsequent intervals were 12–24 months long. The intervals were determined based on the time of QOL (SF-36 and WOMAC) assessment, so that comorbidity scores in the study period prior could be correlated with the QOL scoresBack to article page