L: low risk of bias; M: moderate risk of bias; H: high risk of bias; N: number of patients; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; IV: intravenous; NR: not reported; RA: rheumatoid arthritis; TKA: total knee arthroplasty; PMMA: polymethyl methacrylate; OA: osteoarthritis; ROM: range of motion. This evidence concerns the gene CRP and rheumatoid arthritis.