Abstract: Objective To investigate the clinical effectiveness of arthroscopic in situ suture repair through Endobutton suspension fixation for partial injury of anterior cruciate ligament (ACL). 
Methods Thirty-eight patients with ACL partial injury were treated by arthroscopic in situ suture repair through Endobutton suspension fixation. The pre- and post-operative evaluation of knee stability was performed using anterior drawer test and Lachman test. Lysholm score and the international knee documentation committee (IKDC) score were used for assessment of knee function, and Likert five-level scale was used for postoperative patient satisfaction. 
Results The average duration of operation was (65.08±13.67) min. All patients achieved one-stage healing of incision, and no complications were reported, such as vascular injury, nerve damage and articular infect. All patients were followed up, and the duration ranged from 2.1 to 5.6 years, with an average of (3.10±0.89) years. At the last follow-up, Lachman test was degreeⅠpositive and anterior drawer test was negative in two patients. The other cases were negative for Lachman test and anterior drawer test. The Lysholm score and IKDC score were increased compared with those before operation (P＜0.05). For the evaluation of patient satisfaction, 16 cases were very satisfied, 20 cases were relatively satisfied, and 2 case was satisfied. The total patient satisfaction rate was 94.7%. 
Conclusion The arthroscopic in situ suture repair through Endobutton suspension fixation for ACL partial injury can effectively restore the function and stability of the knee joint, and can yield good mid-term clinical results. 

Key words: anterior cruciate ligament injuries, knee joint, suture repair