However, other studies proposed that preoperative health education had no effect on postoperative pain control for joint-replacement patients (McDonald et al. 2004, Kearney et al. 2011). In their review of five independent studies, McDonald et al. (2004) found no significant differences between the levels of postoperative pain experienced by patients who received preoperative education and those who did not. Furthermore, Kearney et al. (2011) found that preoperative education had no significant effect on patients’ pain levels following joint-replacement surgery. These findings may be attributed to the additional guidance provided after surgery, as well as the educational invention prior to surgery.