Medial means towards the middle of the body (towards the other leg), the patella is the knee cap bone, and luxation means displacement from its appropriate position. This is a hereditary condition where the patella doesn’t develop properly.
When the patella is displaced, dogs and cats have trouble unbending or extending their leg, which explains the hopping. MPLs may or may not be significant and may or may not require any medication or medical intervention. MPLs are a hereditary condition that is often associated with multiple other deformities of the bones of the hind leg.
Medial patellar luxation is very common in toy and small dog breeds, but it can also occur in cats and larger dogs. Larger dogs tend to have lateral (not medial) luxation of the patella. This can occur in dogs and cats of any age but tends to be present from birth and progress/worsen throughout life. Approximately 50% of dogs have a medially luxating patella in one knee, while the other 50% have it in both.
Contributing factors to the kneecap being displaced:
Clinical signs depend on severity. There are 4 grades we talk about when we define MPLs:
MPLs can typically be diagnosed during a physical orthopedic exam performed by your vet.
Treatment depends on the severity of the condition. Options may include:
1. Glucosamine/chondroitin supplements (for life) may be recommended by your vet to support joint health regardless of grade/severity.
2. Anti-inflammatory pain medications to reduce pain and swelling of the stifle (knee joint) are often prescribed for Grade II-IV MPLs.
3. Surgery (advised for some Grade III and almost all Grade IV MPLS) can include both orthopedic and soft tissue procedures, some of which are:
Prognosis after surgery:
Medial Luxating Patella in Dogs
Patellar Luxation in Dogs and Cats
Need to speak with a veterinarian regarding MPL in pets or another condition?Book a video consultation with an experienced veterinarian within minutes.