If you have small dogs, you may be familiar with the term floating or luxatingpatellas. Patellar luxation (or floating kneecap) is a common cause of lameness in pets (most notably small dogs).The patella, or knee cap, is a bone that is tucked under a tendon of the quadriceps muscle. The patella usually sits in a grove at the tip of the femur (thigh bone). Patellar luxation (or dislocation) happens when the patella moves out of the grove it normally sits in. It can also be classified as medial or lateral depending on which direction it dislocates.

What causes a luxating patella?
Conformational issues are the most common inciting cause of luxatingpatellas but trauma such as falling from a height or getting hit by a car, can also cause a luxating patella. Small dogs including Yorkies, Boston Terriers, Chihuahuas, Pomeranians, and Miniature Poodles are typically prone to abnormal confirmation to hips, femurs, tibias, or the patellar tendon itself.

What signs do my pet show?
Lameness in one or both back legs, a “bow-legged” stance, or a “knocked knee” stance are the most common signs of luxatingpatellas. Typically the lameness will be intermittent and your pet will hold his/her leg up or in a flexed position. Then sometimes the lameness can spontaneously resolve. I often hear owners declare that their dog would suddenly hold up his/her leg then use it properly again after a few seconds, almost like a “skip.” Luxatingpatellas are not typically painful unless arthritis has formed.

How does my doctor diagnose a luxating patella?
Your doctor will do a physical examination on your dog to determine if he/she has a luxating patella. They will feel the knee when the leg is flexed and in extension. They may also grade the luxation. There are 4 grades of luxatingpatellas with grade 4 being the worst. Radiographs are sometimes taken to evaluate for arthritis and joint effusion. Bloodwork is typically also recommended if the doctor is going to prescribe anti-inflammatories.

How do we treat a luxating patella?
Many dogs can live normal, relatively pain free lives without surgical correction. Sometimes pain medications and anti-inflammatories are needed if the luxating patella is causing inflammation. If the lameness becomes severe, the patient is young and growth plates are involved, arthritis is progressive, or the patient is in constant pain, surgical correction is recommended. There are several techniques that can be done to correct a luxating patella including a fascial release, trochlear wedge or block recession, tibial crest transposition, and lateral imbrication. Prognosis for a full recovery with grade 4 luxations is guarded due to the severity of the orthopedic abnormality and will often result in chronic joint inflammation and boney changes. Dr. Alec Land is our surgeon who performs these types of procedures. After scheduling a consultation with him, he can discuss the best course of action. Over 90% of luxatingpatellas corrected surgically result in a good outcome.