Luxating Patellas and What It Means For Your Boston Terrier

The patella is your dog’s knee cap. Like the human knee cap, it is held in place by a combination of ligaments and the grooved track in which it sits. Unfortunately, sometimes this track can be too shallow and the knee cap can pop out of and back into place. This is called patellar luxation. Although it can be the result of an injury, that is fairly rare. It is usually a genetic issue and it is most common in small breed dogs like the Boston Terrier. Dogs that are going to be bred should always be examined by a veterinarian to rule out patellar luxation. Affected dogs should not be bred.

Grades of Luxation & Symptoms

Like hip dysplasia, patellar luxation is graded from 1 to 4, depending on the severity of the problem.

Grade 1: Bostons with grade 1 luxation have a knee cap that is in its proper place most of the time. It may periodically pop out, causing your dog to yelp and stop putting weight on the leg momentarily. He may skip or hop for a few steps to avoid standing on the affected leg. The patella will pop back into place on its own within a short period of time. Events where it pops occur once a week or less and tend to resolve quickly. Many owners will not necessarily realize that anything is wrong and the condition can remain undiagnosed for many years. Eventually though the popping in and out will result in arthritis and degeneration of the knee joint. Early diagnosis can be key to avoiding a more serious outcome and maintaining quality of life.

Grade 2: Boston Terriers with grade 2 luxation will require the knee to be manipulated back into place but once it’s there, it will stay in place for a while. It is easier for owners to spot grade 2 luxation as the joint will be held awkwardly and your dog will put no weight on it until the knee cap is back in place. Like grade 1 luxation, grade 2 will result in knee arthritis sooner or later.

Grade 3 & 4: Dogs with grade 3 and 4 luxation are in pain. The knee cap remains outside the groove most of the time in grade 3 but can be manipulated back into place where it will remain temporarily. In grade 4, the patella will not stay in the groove at all. This is very hard on the knee joint. Arthritis, stretched ligaments, and, eventually, bone on bone grinding at the joint. The arthritis tends to set in quite early and the pain can be substantial. In these cases, surgery is often the only option. Thankfully, the surgery for patellar luxation is somewhat less complicated and less expensive than many other orthopedic surgeries.


As mentioned above, grades 3 and 4 are usually treated surgically but there is lots that can be done for grades 1 and 2. Although surgery is an option, there are many less invasive treatments. One of the key aspects to caring for any knee issue is to keep your Boston Terrier at a healthy weight and well-muscled.  Excess weight just increases the stress the joint is under and brings on arthritis and joint degeneration much faster than would otherwise occur. By keeping your pet active and well-muscled you provide additional support to the patella by the muscles and ligaments surrounding it. These can help hold the knee cap in place, reducing incidences where it pops out.

Chiropractic treatments, massage, and physiotherapy can all help keep the patella properly aligned and delay onset of arthritis. You can also use supplements such as glucosamine chondroitin to provide additional support. Pain medication and anti-inflammatories can be used in more advanced cases to maintain quality of life. Catching the problem early and treating it promptly can make a huge difference in how joint degeneration progresses. Whenever your Boston does something that strikes you as odd, it is wise to have your veterinarian check it out. In most cases, early detection makes treatment easier, cheaper, and more effective.

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