Had this problem with an ESS, there are a number of different operations available, all differing in cost, but most are based on having a plastic ring inserted into the joint to keep the thigh and lower leg together. My ESS still works for short periods but his leg is not the same.
The standing jump is very bad on Cruciates - the sudden and explosive contraction and then expansion of those muscles in the back legs, can easily rupture the ligaments.