Luxating Patella Surgery in Dogs: Our Vet Surgeon Explains

I see dogs suffering from luxating patella on a regular basis in practice, and many of these are candidates for surgery. Patella luxation can be a complicated condition and it’s not surprising that many owners are intimidated with the options they are presented with for their canine companion. Following is a list of frequently asked questions that will aim to shed some light on what luxating patella surgery is and when it can help your dog.

Patella luxation is a common condition affecting mainly small dogs, and refers to the ability of the patella (knee cap) to slip out of place. The knee cap usually sits in a groove on top of the knee joint within a tendon, where it slides up and down as your dog’s leg moves.

Dogs suffering from patella luxation have a shallow groove, which allows the knee cap to dislocate out of position. Because of the tendency of the patella to spontaneously pop in and out, dogs affected may be walking fine on their back legs one moment, followed by limping and holding the leg up the next. 

What is luxating patella surgery?

Luxating patella surgery aims to achieve two goals: Firstly to deepen the groove that the patella sits within and secondly to move the point at which the tendon holding the patella in place attaches. The hope is that by combining these two techniques, the patella is moved into better alignment where it is less likely to pop out of place. 

The whole procedure is performed under a general anesthetic and involves making an incision on the side of the knee to gain access to the joint. Metal pins are placed within your dog’s knee joint to hold everything in place once it has been realigned. X-rays are usually taken before and after the procedure to assess how successful it has been. 

How will luxating patella surgery help my dog?

Ultimately, if successful, luxating patella surgery aims to re-stabilize your dog’s knee joint thus allowing them to walk on their leg again pain-free. Surgery is the only way to resolve persistently luxating patellas. 

What happens if I do not do the surgery? Will my dog be in pain?

When the patella luxates out of place it can be very uncomfortable for your dog. It causes their leg to be locked in place, preventing them from being able to bend their knee. Over time, the surrounding soft tissue becomes weaker and the patella pops out of place more often. Eventually, the continuous abnormal rubbing of the patella against the femur can result in arthritis, a painful inflammatory disease of the joint. The leg also becomes generally less stable, predisposing these dogs to other injuries. 

When is luxating patella surgery warranted? What are the signs I should not wait and see?

Patella luxation is given a grade based on how easily and often the kneecap slips out of place. The grading system used is from 1 to 4, with 4 being the worst:

Grade 1 – The patella can pop out but moves back into place immediately.

Grade 2 – The patella pops out and will only move back into place when the leg moves or it is manually put back into place.

Grade 3 – The patella sits outside of the groove all of the time, but can be manually put back into place. 

Grade 4 – The patella sits outside of the groove and cannot be manually put back into place. 

Surgical correction is advised in all cases grade 2 or above. 

How much does the surgery cost?

The cost of luxating patella surgery will depend on many factors, including the degree of patella luxation and which vet performs the procedure – referral-level surgery will be much more expensive than surgery performed in a first opinion practice. The surgery generally costs between $1,500-$5,000, but it’s important to know that post-operative care such as checkups and bandaging are usually not included in those costs. 

Luxating patella surgery is one procedure where having your pet insured can pay dividends. Most pet insurance companies will cover the costs of investigations and procedures related to a luxating patella, provided the condition wasn’t present prior to the policy being taken out. 

What is the success rate of the surgery?

The success rate for luxating patella surgery is very good with more than 90% of dog owners being satisfied with the results according to the American College of Veterinary surgeons. Dogs who undergo successful surgery can return to a normal level of activity. Success rate will depend on the grade of disease that your dog was assigned prior to surgery, with grade 2 dogs having the best outcomes at 100% success rates. Surgery for grade 3 dogs was approximately 89% successful and grade 4 dogs had about a 64% success rate according to this study.

The success rate is lower for large dogs and those dogs with other orthopedic conditions such as hip dysplasia. 

What are the risks or potential complications from the surgery?

As with any major surgery, complications can occur, although these are rarely serious. Apart from the small risk of the procedure not being successful (see section above), complications include:

• Anesthetic-related risk – there’s a small risk when any anesthetic is involved, this risk is higher for older dogs and those with other health conditions.
• Infection – of the external wound or deeper within the joint capsule. Most cases respond to antibiotics, very rarely does the metalwork implanted need to be removed. 
• Implant loosening – the implant is in place to stabilize the knee following surgery, this is not required once the bones have fully healed. Sometimes the implant will loosen with time causing some discomfort; this can be removed if necessary. 
• Osteoarthritis – usually occurs later on in your dog’s life where the joint has been unstable for a prolonged period of time. The sooner surgery is carried out, the lower the risk of arthritis.

Is luxating patella surgery (and recovery) painful for dogs?

Your dog is under a general anesthetic for the duration of the surgery and so won’t feel a thing during the procedure itself. Your dog may feel some discomfort following the procedure, but this usually subsides pretty quickly. This pain is usually associated with the wound made to access the knee joint and normal postoperative inflammation. As time progresses and your dog recovers, they should become gradually less painful with time until they are hopefully pain-free!

How do dogs recover from the surgery?

The typical time for a complete recovery from patella surgery is 8-12 weeks while the bones heal and regain strength. The first 2-4 weeks involve minimal exercise, followed by a gradual increase in the duration of on-the-lead walks. The recovery period will vary greatly between dogs, depending on the age of the dog, grade of luxation and how long the surgery took. 

Are there good alternatives to surgery?

Because patella luxation is a mechanical problem, there is no real alternative to performing surgery. Dogs with grade 1 patellar luxation will likely cope fine without surgery as their kneecap dislocates very infrequently, if at all. While pain relief can provide relief short term, it is not a long term solution. 

Prevention – how can dog owners try to prevent luxating patella issues?

Unfortunately, patella luxation is a genetic condition and there’s therefore little owners can do to prevent it. While restricting exercise might reduce the frequency of the patella luxating, it isn’t a long term solution. Hydrotherapy and physiotherapy can help in preventing a recurring luxating patella following surgery. 

Example dog undergoing luxating patella surgery: Rufus

Rufus was a 3-year-old shih-tzu who first came to the vet as he had developed a ‘hop’ when out on walks. It wouldn’t happen every time, but when it did he seemed in extreme pain, however very shortly afterward he would return to normal as if nothing had happened. This is the classic presentation of luxating patella – as the patella locks out of place, the dog can’t put weight through their leg at all, but then once it pops back into position the dog is back to normal. 

We first tried anti-inflammatory medication to see if that helped the issue – it did provide Rufus some relief, but didn’t decrease the frequency of the ‘hopping’ episodes. In fact, over time rufus’ patella became locked out of position for longer periods of time. Rufus was therefore booked in for further investigations and X-rays. On examination, Rufus’ luxating patella was graded at a borderline between grade 2 and 3, therefore surgery was suggested. The next week, Rufus was booked in and the surgery was a success. Following a recovery period of about 8 weeks with a gradual increase in exercise, Rufus was given the all clear to go back to normal activities and has never looked back since!