In the article "Differential Diagnosis of a Patient Presenting With a Knee Effusion," by K. Sue Hoyt, RN, PhD, FNP, APRN, BC, CEN, FAEN, and Amy Smith Peard, MSN, ENP, CEN, CNS, published in Advanced Emergency Nursing Journal, Volume 29, Number 3, pp. 209-227, incorrect images inadvertently appeared in Figures 3 to 6. The corrected figures appear in the online version of the article, available at http://www.AENJournal.com.