ObjectiveTo clarify the intervention guidance of return to sports WeChat applet and evaluate the rehabilitation effectiveness after anterior cruciate ligament (ACL) reconstruction. MethodsBetween September 2020 and September 2022, 80 patients who met the selection criteria and underwent ACL anatomical single bundle reconstruction were selected as the research objects. According to the double-blind random method, they were divided into the applet group and the regular group, with 40 cases in each group. Patients in the applet group were rehabilitated under the guidance of the return to sports WeChat applet, and the patients were asked to perform the test once a month after operation, including patients’ subjective scores [Tegner score, knee injury and osteoarthritis outcome score (KOOS), International Knee Documentation Committee (IKDC) score, American Hospital for Special Surgery (HSS) score], psychological assessment [ACL recovery sports injury scale (ACL-RSI) score], jumping test, balance test, bending angle test. Patients in the regular group were followed up by doctors and nurses regularly by telephone every month. All the patients were reexamined at 3, 6, 9, and 12 months after operation, and the range of motion of the knee joint with 6 degrees of freedom (flexion and extension angle, varus and valgus angle, internal and external rotation angle, anteroposterior displacement, superior and inferior displacement, and internal and external displacement) recorded by Opti_Knee three-dimensional knee joint motion measurement gait analysis system was observed. The anterior tibial translation difference (ATTD) was measured by Ligs knee measuring instrument when a forward thrust of 120 N was applied to the posterior part of the proximal tibia. Tegner score, IKDC score, KOOS score (including KOOS-Pain score, KOOS-Symptoms score, KOOS-Activities of daily living score, KOOS-Sport score, and KOOS-Quality of life score), HSS score, ACL-RSI score, jumping ability, balance ability, patients’ satisfaction with the rehabilitation process, and ACL healing grading according to ACL continuity and signal intensity shown by MRI. Results There were significant differences in various indicators between different time points after operation in the two groups (P<0.05). At 3 months after operation, except that the ACL-RSI score of the applet group was significantly higher than that of the regular group (P<0.05), there was no significant difference in the other indicators between the two groups (P>0.05). At 6 months after operation, the ACL-RSI score, IKDC score, Tegner score, KOOS scores of different items, HSS score, balance and jumping ability of the applet group were significantly higher than those of the regular group (P<0.05), and there was no significant difference in the other indicators between the two groups (P>0.05). At 9 months after operation, there was no significant difference in all indicators between the two groups (P>0.05). At 12 months after operation, 27 cases (67.5%) in the applet group and 21 cases (52.5%) in the regular group returned to sport, with a significant difference of the return to sports incidence between the two groups [RR(95%CI)=1.50 (1.00, 2.25), P=0.049]. In the applet group, 27 cases were very satisfied with the rehabilitation process, 10 cases were satisfied, 2 cases were basically satisfied, and 1 case was not satisfied, while 19, 13, 5, and 3 cases in the regular group, respectively. The satisfaction degree of the applet group was significantly better than that of the regular group (P=0.049). MRI examination of the two groups showed that the ACL was continuous without secondary rupture or necrosis. The ACL healing grade of the applet group was 31 cases of grade 1 and 9 cases of grade 2, and that of the regular group was 28 cases of grade 1 and 12 cases of grade 2, there was no significant difference in ACL healing grade between the two groups (P=0.449). ConclusionThe application of return to sports WeChat applet in the rehabilitation of patients after ACL reconstruction can significantly reduce the fear of return to sports and improve the rate of return to sports. The return to sports WeChat applet is convenient to operate, with high utilization rate and high patient compliance, which significantly improves the satisfaction.