The study aimed to explore the impact of knee joint muscle energy technique on knee joint pain, functional scores, range of motion, muscle strength, and balance in individuals who had undergone knee joint arthroplasty due to osteoarthritis. Thirty patients aged 65 or older, diagnosed with osteoarthritis and having received knee joint arthroplasty at a Daegu-based orthopedic hospital in South Korea, were randomly assigned to either an experimental (muscle energy technique) or control group (static stretching). Over a 6-week period, both groups engaged in 12-minute sessions three times a week. Assessment tools included the Visual Analogue Scale (VAS), Knee Joint Function Score (LKS), proprioception, handheld dynamometer (HHD), and a plantar pressure measurement device. Statistical analyses employed paired t-tests for within-group comparisons and independent t-tests for between-group comparisons. The study revealed significant differences (p