There is no role of acupuncture in ACL tear Since you are young , you need arthroscopic ACL reconstruction

ACL is strong ligament in knee which stabilises knee. When it's torn, knee does not remain stable. Patient feels some give way sensation but there is NO PAIN. This very dangerous because patient doesn't feel any problem except occasional instability. After repeated episodes of instability, Meniscus gets torn. This causes pain. Main treatment for ACL tear in symptomatic patients with instability is ACL reconstruction. If meniscus is also torn, it needs to be repaired. Early surgery gives excellent outcomes! Dr Prashant Parate Shoulder and Knee Surgeon Arthroscopy, Joint Preservation and Joint Replacement Specialist

ACL is required for stabilising the knee in certain angle while walking fast or running. If that is torn completely your knee will buckle repeatedly causing other structures vulnerable for damage and leads to early arthritis. Hence needs reconstruction to get back the stability. Same injury in aged person with sedentary lifestyle or already arthritic knee may not need surgery as activity level is low. Alternate therapy will help you make you feel better but will not heal the ligament. Some hamstring and quadriceps strengthening will substitute the ACL function partially.