4. Discussion
postoperative knee pain, postoperative pain, knee flexion ROM, pain, TKA, knee pain
In this study, we investigated the effects of a 1-week comprehensive FR intervention on pain, knee joint ROM, isometric knee extensor muscle strength, walking speed, and balance function from the second to the third postoperative week in patients with TKA. The results showed that adding one week of FR intervention to regular physical therapy significantly improved pain scores at stretching, but there was no synergistic effect on the other parameters.In general, knee pain is known to occur after TKA, and Seo et al. reported that 60% of patients who underwent TKA experienced severe postoperative knee pain, whereas 30% experienced moderate pain [On the other hand, we considered increasing knee joint ROM through FR intervention on the anterior thigh muscles, specifically the knee joint extensors; however, there was no significant interaction between knee flexion ROM in the FR and control groups. Kiyono et al. reported a significant increase in ROM after five weeks of an FR intervention [Both the FR and Control (regular physical therapy only) groups significantly improved 10-m walking speed, TUG time, time to stand on one leg, and isometric knee extensor muscle strength from postoperative weeks two to three. However, there were no significant differences in the changes in these variables between the FR and control groups. A meta-analysis of the effects of the FR intervention on motor function in young subjects reported no change in performance after several weeks of FR intervention training programs [Stretching is a typical postoperative ROM exercise for TKA patients but stretching may also put stress on the wound. Conversely, FR intervention is an approach that can reduce pain by increasing tissue temperature and stimulating proprioceptors without putting stress on the wound. Additionally, FR intervention can approach the quadriceps muscle without putting stress on the wound. Therefore, FR intervention for the quadriceps muscle is used in clinical practice and, as a result, early postoperative knee pain can be suppressed. Early postoperative pain after TKA has been linked to persistent knee pain and reduced walking speed three months post-surgery, suggesting the importance of effective early pain control. Previous research has also found that the severity of pain on postoperative days one and five is associated with improved motor function at three months post-surgery [