Teenagers diagnosed with Osgood-Schlatter disease, or OSD, experience knee pain resulting from tendon inflammation below the kneecap. It's usually due to trauma, especially in young athletes. However, the term OSD is not used in a canine's diagnosis.
Tibial Tuberosity Avulsion
A dog's tibia, or shinbone, includes the tibial tuberosity, a large bump above and in front of the bone, underneath the knee. It attaches the dog's kneecap by a tendon from the animal's quadriceps, muscles located on the front of the thigh. If the tibial tuberosity fractures, an avulsion might occur. That means a small bit of bone becomes displaced because of the quadriceps muscles pulling. Symptoms include lameness, typically the sudden inability to bear weight on a hind leg. The dog will be in pain, and the knee joint might swell up.
Just as Osgood-Schlatter disease occurs in adolescent humans, tibial tuberosity avulsion is often a condition of growing dogs, the canine equivalent of teenagers. It also can occur in puppies and adult canines. Often, minor trauma causes the displacement, such as playing too roughly with another dog, jumping off stairs or furniture or any of the numerous ways rambunctious young animals manage to harm themselves.
Diagnosis and Treatment
Your veterinarian likely will examine your dog and perform X-rays of both hind legs. That's because the displacement might be quite small and it's easier to compare images of both legs to locate the problem. For best results, your vet likely will recommend that your dog have surgery to put the displaced segment back into its proper position. For mild displacements, or if the surgical expense is prohibitive, the vet can apply a cast to the affected leg and prescribe anti-inflammatories to ease discomfort. However, this option requires your dog's leg to be extended for at least two to three weeks, followed by exercise restrictions for a few more weeks.
Surgical Recuperation and Recovery
You must keep your dog quiet while he recuperates, which is often easier said than done. If your dog had surgery, your vet also will give you instructions for mild physical therapy several times a day, consisting of gently flexing the knee. She'll also show you how to massage the quadriceps muscles above the knee. You can take your dog out for brief potty breaks a few times daily. By the second week, your dog should start walking normally and you can take him for longer, slow walks. Your vet will check your dog's progress, including taking X-rays, and prescribe additional exercises. Your dog should return to normal within six weeks of the surgery.