Effects of low-intensity pulsed ultrasound on pain and recovery of range of motion after total knee arthroplasty: preliminary study

Introduction: Pain and limitation in knee range of motion (ROM) during the immediate postoperative period are the common outcomes after total knee arthroplasty (TKA) procedure. Low-intensity pulsed ultrasound in combination with cryotherapy is a promising physiotherapy intervention which has been shown to help in relieving inflammation and improving recovery of joint function of patients with TKA. However, the documentation on the effects of combining low-intensity pulsed ultrasound in post-operative rehabilitation programme is limited. Therefore, this study was conducted to determine the effects of low-intensity pulsed ultrasound as in-addition to conventional physiotherapy on pain and knee ROM in patients with TKA. This study also aimed to assess the relationship between the recovery of knee ROM and pain following the combined intervention. Method: This was an assessor-blinded quasi-experimental study among patients with TKA at the Universiti Kebangsaan Malaysia Medical Centre. Participants were alternately allocated to receive either pulsed ultrasound-added conventional physiotherapy (n=10, experimental group) or conventional physiotherapy alone (n=10, control group) for 3 weeks. Visual analogue scale and goniometer were used to assess post-operative pain and active knee ROM, respectively. The outcomes were evaluated at baseline (post-operative day 2), week 1 and week 4 after TKA. Mixed model ANOVA and Spearman’s rho were used to analyze the data. Result: This study showed a significant time and group effects for pain and knee ROM following interventions. The pain score decreased (p 0.05). Discussion and Conclusion: The findings from this study provide physiotherapists and other healthcare providers knowledge regarding the effects of combining low-intensity pulsed ultrasound in post-operative rehabilitation following TKA. The combined intervention demonstrated more promising results in pain alleviation and recovery of knee motion following TKA. Further study with larger sample size is needed to establish this study findings. Keywords: low-intensity pulsed ultrasound, physiotherapy, total knee arthroplasty