The knee joint can be vulnerable to injury in dogs just as it is in people because the bones are attached through soft tissues known as ligaments. I received a call a couple of weeks ago from a friend saying, “Kathleen, I was at the dog park with Lea and she cried out and pulled up lame. She won’t bear weight on it. What do you think is wrong?”
Since I’m not a vet, I’m not qualified to diagnose injuries but this particular one sounded to me like a ‘classic’ cruciate ligament tear or rupture. My friend didn’t want to pay after-hours vet prices on the weekend if he didn’t have to but equally didn’t want to wait to see a vet if her condition was serious or life-threatening.
I suggested that he rest Lea, keep her warm, dry and comfortable and go to the vet if there was an immediate change in her condition. Otherwise, if she still wasn’t weight-bearing on Monday, then a visit to their regular vet was warranted.
As it turned out, Lea’s condition didn’t change over the weekend and a visit to the vet confirmed a cruciate ligament tear. She’s now resting in the hope that the tear will heal itself.
In many cases, cruciate ligament injuries are partial tears and surgery isn’t required. In others, full rupture of the ligament may mean that surgical repair is required. Some dogs still need ongoing support for their legs regardless of whether the ligament was repaired surgically or not. Leg braces that are made from a cast of the dog’s leg work well in many cases.
I work on dogs with these injuries in my canine massage practice. Laser therapy helps to relieve the pain of the injury and support healing. Passive range of motion exercises assist in keeping the leg joints mobile, but without pressure on the knee joint. And hydrotherapy works wonders when the dog is ready for this type of more strenuous (but non-weight bearing) exercise!
Here’s a great video, courtesy of the folks at Vetstoria and YouTube about the symptoms and diagnosis of cruciate ligament ruptures.
DoggyMom.com 
I feel your advice is good, I have been a vererinary assistant for 40 yrs, I assist with the cruciate surgery, the Veterinarian I work with performs this procedure old fashioned, The Doctor cleans the knee joint of an complete tears, then he takes a strip of the Faciel lata tissue, leaving the lower portion attached, then drills a hole thru the tibial cress ( lower Knee) and pulls the strip through, then takes the tissue and puts it through the where he cleaned the cruciate ligament. Making a faux ligament. this has been quite successfull, However, the difficult portion is 12 weeks of on leash care, no running, jumping etc….