Arthro-IonX could be helpful especially if the ligament is not completely torn. It helps to reduce pain,and inflammation and stimulate healing. Try to limit the amount of running and jumping while the knee is still weak. Usually leash walks are in order to prevent further injury. If it is severe you can have a custom knee brace made to provide stability.
The oligotherapeutic mineral base found in the IONX products helps the body to better utilize the other nutritional substances given for a synergistic response and faster healing. The supplements I recommend are digestive enzymes with each meal, MSM, Canine probiotics, and Omega 3,6,9. Ligaplex 1 by Standard Process contains nutrition for ligaments. Also be sure to give sufficient fresh water that is free of chlorine and fluoride. If you can gradually phase into a grain free diet that can be helpful too. The other thing that is sometimes beneficial is to have a certified veterinary chiropractor check for spinal and hip alignment and make any necessary corrections.
Please let us know how you progress or if you have any other questions.