4. Discussion
knee reduced pain, postoperative knee pain, TKA, pain
SECONDARY, CONTRACTION, BLIND
In this study, there was a significant difference in the primary outcome between the two groups, i.e., the difference in VAS scores before and after CPM on postoperative day 14, with a decrease in the bilateral group and an increase in the unilateral group. The secondary outcome, i.e., the difference in ROM before and after CPM on postoperative day 14, and the 10 m test results were not significantly different between the groups. Simultaneous exercise of the healthy side during rehabilitation with CPM was indicated to decrease pain during exercise on the operated side, while no significant improvement in motor function was observed.The number of patients undergoing TKA has been steadily increasing, with a projected 3.48 million patients expected to have undergone the procedure in the United States by 2030 [Postoperative CPM was thought to increase pain, which decreased after the first CPM on postoperative day 2 in both groups. Loading and repetitions performed for contraction failure increased postoperative knee pain, although this increase was transient [The limitations of this study include the unblinded design, the small sample size, and the fact that no confirmatory analyses could be performed to determine whether the effects were truly due to EIH. This study could not be performed with blinding, and patients become aware of their group at the time of CPM. This inability to blind may have affected the outcome. Although the sample size was small, we believe our results are reliable because we used statistically evaluated values. Although the effects of EIH could not be confirmed because we did not measure thresholds, tolerance, and/or rating of noxious stimuli, exercise for the healthy knee reduced pain during CPM. These findings represent a novel aspect of exercise therapy in the acute postoperative period. However, additional research is needed, and novel rehabilitation methods are expected to be developed based on the results of this study.