OBJECTIVES: To compare the effect of medial femoral muscle stimulation with medium frequency electrotherapy and conventional rehabilitation therapy on knee function recovery after anterior cruciate ligament (ACL) reconstruction. METHODS: Medical records of 50 patients with ACL reconstruction, treated in our hospital between July 2019 and December 2020, were retrospectively analyzed. Patients were divided into control group and study group (n=25, 18 males and 7 females in each group), based on the rehabilitation method used. The control group included patients that received conventional rehabilitation therapy, active quadriceps femoris exercise, traction, and acupuncture. The study group included patients that received medium frequency electrotherapy to stimulate the medial femoris muscle in addition to conventional rehabilitation therapy. The limb circumference recorded before and after the treatment was compared between the two group. The Lysholm scores of the two groups were compared to assess knee function, knee range of motion, and knee motor comfort assessed by visual analogue scale (VAS). RESULTS: We found similar thigh circumferences, Lysholm scores, knee motion ranges and VAS scores between the patients in both groups before the treatment (P > 0.05). After the treatment, the thigh circumferences and motion ranges were larger, the Lysholm scores higher, and the VAS scores lower in patients of the study group than those in patients of the control group (all s < 0.05). CONCLUSION: Intermediate frequency electrotherapy to stimulate the medial femoris muscle can improve knee function and motion range and reduce the patient's pain after ACL reconstruction.