Hi, I am Dr. Jeff. I will try to help you. Please feel free to follow up if any more information is needed. Clicks like this can occur for a number or reasons. With this surgical technique, there is a knot in the suture. Fascia can pass over this knot resulting in a click or pop. If this is the case, it is very unlikely to cause an issue. You may see a little more inflammatory or scar tissue near the know, but it should not have a serious effect on recovery. In some cases (and this breed would not be high risk), there can be a concurrent luxating patella (knee cap pops in and out) which can lead to a pop when the knee goes through its range of motion. Chances are, your vet would be able to feel this plus, this is not a high risk breed.
Finally, a secondary injury in ACL injuries, is a damaged Meniscus (padding that sits on top of the tibia). If the meniscus is not addressed properly, this can cause it to move back and forth in the joint. When it snaps back into place, a pop or click can occur. I would ask your vet about the condition of the meniscus and how it was addressed during surgery. If your vet states that then meniscus was "released" or removed, then this is less likely of an issue.
So, if she seems to be consistently improving, she will likely be okay. Remember, arthritis is going to occur no matter what. By having the surgery performed, you greatly slow the progression. Certainly, if use of the leg is worsening, then I would certainly be more concerned about an issue. I hope this helps and gives you direction.
Thanks
Dr. Jeff