Luxating Patellas - What Can You Do?
What is a luxating patella?
A luxating patella (kneecap dislocation) occurs when the knee cap moves out of its natural position. The patella normally lies in a grove that is coated with cartilage at the end of the thigh bone just above the joint space. It is bean or almond shaped and it's job is to help with extension of the knee. The end of the quadriceps muscles form the patella tendon and attach it to the shin bone on a bump called the tibial tuberosity. The patella sits inside the tendon and rides in the groove mentioned above. When quadriceps muscles contract, they pull on the tendon and the knee cap, resulting in extension of the knee. If the patella is pulled out of its normal groove with knee extension, this is called a luxating patella. If it is pulled toward the inside of the leg it is referred to as a medial patellar luxation (MPL). If it is pulled toward the outside of the leg it is referred to as a lateral patellar luxation (LPL).
The causes of this condition can be congenital, genetic and/or traumatic. Certain breeds are more likely to have or develop this condition. These breeds are Miniature and Toy Poodles, Maltese, Jack Russell Terriers, Yorkshire Terriers, Pomeranians, Pekingese, Chihuahuas, Cavalier King Charles Spaniels, Papillons and Boston Terriers. Large breed dogs prone to this condition include Labrador Retrievers, Golden Retrievers, Akitas, Malamutes, Boxers, Huskies and St. Bernards. Any dog with minimal hock angulation or poor body condition can also develop luxating patellas.
This condition is usually diagnosed early in life when the owner notices that the dog limps, skips or stretches the limb behind them repeatedly. Some dogs with patellar luxation will sit with the knee extended out to the side. All of the symptoms however are intermittent meaning they come and go until there is damage to the cartilage and arthritis is starting to set in.
Luxating patellas can lead to a ruptured cranial cruciate ligament (commonly known as the ACL in humans). It is proposed that at least 15% to 20% of dogs with patellar luxation will eventually rupture their cranial cruciate ligament because the patella luxation changes how the knee works and thus puts more stress / strain on the cruciate ligament and in chronic cases the arthritic changes in the knee set off an inflammatory cascade that weakens the ligaments of the knee.
Luxating patellas are diagnosed during a pets physical examination with their veterinarian and are graded based on the severity of the condition. Grade 1 means the kneecap will pop out of place but can easily be put back into a normal position. Grade 4 means the kneecap is stuck and sits outside the groove at all times. Grades 2 and 3 are in between. is usually diagnosed by feel and is assigned a grade based on the severity of the condition.
Dogs with Grades 1 or 2 can do quite well without surgery and often can recovery with rehabilitation therapy alone. Dogs with Grade 3 or 4 luxations typically require surgical repair to prevent further pain and arthritic changes from occurring.
If your dog suffers from this condition, the earlier you intervene the less likely your pet will develop arthritis and you may be able to prevent him from going through surgery. The best way to support your pet is to start supplements and schedule an appointment with a rehab veterinarian to start a safe and effective home exercise program.
Supplements
Omega 3 fatty acids (fish oil) - these are natural anti inflammatories and can be very helpful in slow the onset of arthritis due to inflammatory mediators in the knee joint
Glucosamine / Chondroitin / MSM - these are the building blocks to healthy cartilage / joint tissue and can help to keep the joint healthy
Polysulfated Glycosaminoglycans - these injectable medications help to promote healthy cartilage in the joint.
There are also a few whole food supplements on the market that can support healthy musculoskeletal and ligamentous tissues but are available only with a prescription.
Exercise
xercise is the other component that can be very helpful in correcting patellar luxation. If you pet has medially patellar luxation then it is likely that his quadriceps and lateral thigh muscles are weak. If your pet has lateral patellar luxation then it is likely that his quadriceps and medial thigh muscles are weak. With the help of a rehabilitation veterinarian a home exercise program can be developed to strengthen these areas in the earliest stages before problems have developed.
What to do next
If your veterinarian has indicated that your pet has patellar luxation here are the best steps to take.
1. Start Glucosamine / Chondroitin Supplementation (talk to your vet about the product they prefer)
2. Start Adequan or Pentosan Injections (talk to your vet about the product they prefer)
3. Have xrays of the knees and hips taken to evaluate the joints for arthritis or other changes
4. Ask your vet for a referral to a rehabilitation veterinarian or therapist to start a home exercise program.
(If your pet is a puppy ask for a referral to a rehabilitation veterinarian or therapist right away as we may be able to prevent the issues from developing at all)