Ganglion cyst of Anterior cruciate ligament (ACL) is rare and is lack of specific symptoms and signs, as a result, it is not easy to be diagnosed. In this study, we reported a 35-year-old male with presumed ganglion cyst of ACL, the case was demonstrated by MRI and further confirmed by arthroscopy and pathology. In order to avoid recurrence, complete resection of cyst and cyst wall is highly recommended. Autograft Hamstring Tendon Augmentation was performed improve the stability of the knee .18 months postoperatively, the patient was asymptomaticand clinical examination was normal, Therapeutic result is satisfactory. After the resection of cyst, it is advised to test the strength of the ACL, if the stability of the knee is reduced significantly, The auto graft augmentation of ACL repair surgery may be necessary.
