CRP and synovitis: LB 95% CI: Lower bound of 95% confidence interval; UB 95% CI: Upper bound of 95% confidence interval; TS: transient synovitis; LA: Lyme arthritis; SA: Septic arthritis; WBC: white blood cell; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; PMNs: polymorphonucleocytes