Introduction: Total knee arthroplasty (TKA) commonly cause physical impairments, which necessitate physiotherapy post-operatively. Low-intensity pulsed ultrasound is an adjuvant treatment to conventional physiotherapy; however, its effects on TKA recovery require further investigation. The study aimed to ascertain the outcome of adding low-intensity pulsed ultrasound therapy into conventional physiotherapy on recovery from physical impairments after TKA. Methods: This assessor-blinded quasi-experimental study was conducted in a tertiary medical centre in Central Malaysia. Patients with TKA due to grade III and IV knee osteoarthritis (Kellgren-Lawrence grading system) were alternately allocated into either an experimental group (n=10) or a control group (n=10). Other than low-intensity pulsed ultrasound as received by the experimental group’s participants, the two groups received the same amount and content of conventional physiotherapy. Participants’ pain, knee swelling, active knee flexion range, and quadriceps strength were assessed at baseline, week 1 of the intervention, and the 1-week follow-up. The two interventions’ effects were analysed using a mixed model ANOVA. Results: The pain score and knee swelling decreased (P<0.05), while the knee flexion range and quadriceps strength increased significantly (P<0.001) after both interventions. The experimental group had a significantly lower pain score [3.07(2.18) at visual analogue scale] and a greater active knee flexion range [80.48(26.42) degrees] compared to the control group [pain score=4.29(1.54); knee flexion=67.00(25.15) degrees] following the interventions. There were no significant interaction effects for all outcomes. Conclusion: The combination of low-intensity pulsed ultrasound into a conventional physiotherapy program demonstrated more promising results in pain alleviation and knee motion recovery following TKA.