Have you noticed your Chihuahua limping or holding one of their legs up when they walk? They could have a condition known as Patella Luxation. In laymen terms it is a floating kneecap. It can progressively get worse as time goes by so it is something your veterinarian should check out.
The patella, or kneecap, is a small bone, which normally sits in the tendon of the extensor muscles (the quadriceps muscles) of the thigh. The patella normally lies in a groove within the thighbone in the knee.
Patellar luxation or dislocation is a condition where the kneecap rides outside the femoral groove. It is one of the most common knee joint abnormalities in dogs. Patellar luxation is most common in Chihuahuas, as well as, in other toy and miniature dog breeds such as Yorkshire Terriers, Pomeranians, Pekingese and Boston Terriers.
Here is a great video that explains it all very well:
Patellar luxation can occur after a traumatic injury to the knee or as a result of a genetic malformation of the stifle joint. Traumatic luxation is the result of disruption of soft tissues and forceful dislocation of the patella. Your Chihuahua will have a very difficult time walking on the leg as the condition is very painful.
If corrected early, your dog could have a good prognosis. Congenital or developmental patellar luxation can be associated with varying degrees of deformities of the hip and stifle joint, as well as the tight and leg bones.
The signs of patella luxation will vary depending on the severity of the condition and on the presence of concurrent degenerative arthritis. Your Chihuahua may exhibit some of the following signs:
• Prolonged abnormal hind limb movement
• Occasional skipping
• Hind limb lameness
• Sudden lameness
• Holding up the hind limb
There are different grades of severity for this condition. It goes from Grade 1 to Grade 4. In grade 1, you may not even notice your dog has a problem. The higher the grade number, the more severe the condition is.
Your dog’s veterinarian will need to perform various tests including (ACVS):
• Palpation of the knee under sedation
• X-rays of the hind limb
• Analysis of the synovial fluid (the fluid that lubricates joints)
• Blood tests and urine analysis
Treatment and Management
You can do things to help your dog be more comfortable such as having stairs and ramps available for them. Vitamin and mineral supplements along with joint supplements can sometimes help too.
Although some dogs can live their entire lives with this condition and never have it progress, many of the cases will eventually need surgical treatment, which may consist of fastening the kneecap on the outside of the bone to prevent it from sliding towards the inside or deepening the groove of the thighbone so that it can better hold the kneecap. Chihuahuas who also have degenerative arthritis may also need medical treatment, which may include analgesics and chondroprotectants such as chondroitin sulfate. After surgery your dog will need frequent low-impact exercises such walking. Kneecap dislocation is genetically inherited; therefore, the breeding of affected dogs is highly discouraged.
Has your Chihuahua been diagnosed with Patella Luxation? Or do you suspect they may have it? Leave a comment and let me know your experience with this condition.
American College of Veterinary Surgeons (ACVS). Patellar Luxation. Retrieved on February 20, 2016 from: https://www.acvs.org/small-animal/patellar-luxations
Hettlich, B. (2014). Patellar Luxation. World Small Animal Veterinary Association World Congress Proceedings. The Ohio State University, Columbus, OH, USA