Objective : To evaluate the effects of manual lymphatic drainage (MLD) on knee swelling and the assumed consequences of swelling after total knee arthroplasty (TKA). Design : Randomized controlled trial. Setting : Primary care hospital. Participants : Two groups of 30 patients were randomized before TKA surgery (N=60; 65% women ; mean age, 70.7±8.8y; weight, 77.8±11.3kg; size, 1.64±0.08m; body mass index, 29.9±4.1kg/m2). Interventions : Participants received either 5 MLD treatments or a placebo, added to rehabilitation, in between the second day and the seventh day after surgery. Main Outcome Measures : Swelling was measured by blinded evaluators before surgery and at second day, seventh day, and 3 months using bioimpedance spectroscopy and volume measurement. Secondary outcomes were active and passive range of motion, pain, knee function, and gait parameters. Results : At seventh day and 3 months, no outcome was significantly different between groups, except for the knee passive flexion contracture at 3 months, which was lower and less frequent in the MLD group (−2.6°; 95% confidence interval, −5.0° to −0.21°; P=.04; absolute risk reduction, 26.6%; 95% confidence interval, 0.9%–52.3%; number needed to treat, 4). The mean pain level decreased between 5.8 and 8.2mm on the visual analog scale immediately after MLD, which was significant after 4 of 5 MLD treatments. Conclusions : MLD treatments applied immediately after TKA surgery did not reduce swelling. It reduced pain immediately after the treatment. Further studies should investigate whether the positive effect of MLD on knee extension is replicable.