Surgery Slide Show

Warning: This slide show contains graphic imagery that may not be appropriate for children!

Subluxating Patella

The canine patella is equivalent to the human knee. Dogs have a ligament called the patellar ligament which slides in the patellar groove, a ridge running along the front side of the dogs knee on the lower end of the thigh bone. The patella (kneecap) is held in the groove by the patellar ligament. Subluxation (dislocation) occurs when the kneecap pops out of the groove.

The cause of this condition is usually associated either by traumatic injury or a genetic defect. The most common traumatic patellar injury we see is when a dogs’ leg becomes stuck somewhere and the dog struggles to free it. Damage to the patellar ligament then occurs and the kneecap is no longer held strongly within the groove. Genetics plays a very important role in the frequency of patellar luxation. Many small breeds such as Boston Terriers, Pekingnese, Poodles, and Yorkshire Terriers are commonly found to have subluxating  patellas. Either one or both legs are affected, and male or female are equally affected. The patellar groove may be formed  to shallow do to a genetic defect, or the leg may grow bowed. The ligament holding the patella then becomes weakened or damaged and no longer holds the patella in place.

Common signs of a dog having issues with their patella are limping, yelping frequently while exercising, stretching the hind legs frequently, and hopping like a bunny on both hind legs.

We grade the condition between 1 and 4. Grade 1 is when the kneecap easily pops in and out of the patellar groove. Normally there are no signs and the condition is discovered during a routine physical exam by your veterinarian. Dogs with Grade 2 patellar problems will run normally but every so often let out a yelp or hold a back leg up for a few strides until the kneecap pops back into place. Many times these dogs will frequently stretch their hind legs, which pops the patella back in. Grade 3 is when the patella is dislocated most of the time. These patellas can still easily be put back in though not for long. Grade 4 patellas are dislocated all the time and will not go back in without surgery.

Surgery is the only form of correction and is usually recommended for those patients diagnosed with Grade 3 or 4 patella subluxation. (see slide show)  The surgery involves deepening the patellar groove, and thus helping prevent the kneecap from popping out as easily.
After surgery the patient is confined indoors for 4-6 weeks, and only brought outside on a leash. Range of motion exercises are encouraged. We recommend both passive as well as active exercises for the recuperating patient. A great passive exercise is “bicycling” your dogs limbs while he lays on his back or side. This motion helps to loosen muscles and improve circulation. A wonderful active exercise is swimming. You get the full benefits of range of motion without the stress of weight bearing on the limb. Swimming is only encouraged with those animals that are trained to voice commands and can be controlled when out of the water off leash.

To help prevent your pet from developing patellar problems there are a few things you can do. First off,  if your pet is one of the breeds prone to this condition, keep the extra weight off of him. Any unnecessary body conditioning puts undo stress on these limbs. Slow uphill (slight incline) walks help to strengthen the muscles around the patella, and thus help prevent strains on the ligaments.

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