In the report of Pichonnaz , pain intensity associated with walking on the seventh day after knee arthroplasty was 33.3mm. In contrast, in this study, the maximum loading pain at the knee 10 days after knee arthroplasty was 13.0 mm. Ten days after surgery corresponds with the latter stage of the peak inflammatory phase. It is conceivable that the management of pain associated with medication was effective in both groups, and therefore, the effect of manual lymph drainage was obscured.Additionally, the secondary endpoints did not show significant differences between the groups. This is consistent with previous research . Swelling ( inflammatory edema) is affected by obesity. When the skin is stretched due to obesity, tissue pressure is low and thus edema is likely to occur. Compared with Westerners, thinner Japanese have less edema after surgery and may be more likely to show differences due to the intervention. In fact, compared to the BMI of the subjects of the previous study, the subjects of this study showed a low average BMI of 26.0 kg/m2. However, as no significant difference was shown between the groups, we conclude that the difference in physique had little influence on the results of this study.Analysis of the immediate effects of manual lymph drainage was only within the intervention group and deviates from the random design of this study. Therefore, it cannot be determined whether there is an immediate effect. Pichonnaz et al. compared the immediate effects of hypnosis and manual lymph drainage intervention groups in an random and reported that both groups had immediate effects with no significant differences between