Patella certification is also extremely important. We never breed dogs that have luxating patellas. Luxating patellas are extremely common in French Bulldogs and small breeds in general. There is NO way to guarantee that a dog will never develop this condition. There is evidence that loose knees (luxating patellas) have a genetic component BUT it can also be caused by an injury to the knee. It is still important to have all of your breeding dogs checked for this condition. The patella, or kneecap, is part of the stifle joint (knee). In patellar luxation, the kneecap luxates, or pops out of place, either in a medial or lateral position. Bilateral involvement is most common, but unilateral is not uncommon. Animals can be affected by the time they are 8 weeks of age which is usually attributed to being genetic. If it occurs later in life, it could be due to an injury or genetics. This condition is VERY common in bulldog breeds due to their shortened structure. There are varying grades of severity. Only the most severe grades require surgery. Most of the time, if you put your dog on a Glucosamine supplement they will be just fine.