A luxating patella is a kneecap that slips out of its normal position in the groove at the front of your dog’s thigh bone. It’s one of the most common orthopedic conditions in dogs, particularly small breeds, and ranges from a minor quirk you barely notice to a persistent problem that causes pain and lameness. The kneecap can slide inward (medial luxation, the most common direction) or outward (lateral luxation), and severity is graded on a scale from 1 to 4.
How a Dog’s Knee Normally Works
Your dog’s knee, called the stifle joint, is built around three main structures: the bottom of the thigh bone (femur), the top of the shin bone (tibia), and the kneecap (patella). The kneecap sits in a vertical groove on the front of the femur called the trochlear groove. When your dog bends and straightens their leg, the kneecap glides up and down inside this groove, held in place by the quadriceps muscle group, its tendon, and surrounding ligaments.
In a healthy knee, the groove is deep enough and the surrounding soft tissues are balanced enough that the kneecap stays centered between the two rounded knobs (condyles) at the bottom of the femur. When something goes wrong with the depth of that groove, the alignment of the leg bones, or the tension in the soft tissues on either side, the kneecap pops out to one side. That’s luxation.
What Causes It
Most cases are congenital, meaning the dog is born with structural features that set the stage for luxation. A trochlear groove that’s too shallow, a slight rotation or bowing of the leg bones, or an attachment point for the patellar tendon that sits slightly off-center on the shin bone can all allow the kneecap to drift. These structural quirks tend to run in families, which is why certain breeds are heavily predisposed.
Less commonly, a luxating patella results from trauma. A hard impact to the knee, a torn ligament, or a fracture can damage the structures that keep the kneecap in place. Large breed dogs with patellar luxation are more likely to also have related problems like cranial cruciate ligament disease, hip dysplasia, or excessive angulation of the long bones, which complicates both the cause and the treatment.
Which Dogs Are Most Affected
Small and toy breeds are far more likely to develop this condition. Yorkshire Terriers, Pomeranians, Chihuahuas, Miniature Poodles, Boston Terriers, and French Bulldogs are among the most commonly affected. In small breeds, the kneecap almost always luxates medially (toward the inside of the leg). Large breeds can also develop it, though less frequently, and lateral luxation (toward the outside) is more common in bigger dogs. Many dogs develop the condition in both knees.
The Four Grades of Severity
Veterinarians classify luxating patellas into four grades based on a hands-on exam of the knee:
- Grade 1: The kneecap can be pushed out of the groove manually but pops back into place on its own when released. Dogs at this grade rarely show any lameness.
- Grade 2: The kneecap slips out when the knee is bent or with manual pressure and stays out until the leg is straightened or the vet pushes it back. This is the grade where owners typically start noticing the classic “skip” in their dog’s gait.
- Grade 3: The kneecap sits outside the groove most of the time. It can be manually pushed back in, but it immediately slides out again. Dogs at this stage often walk with a persistent limp or a bowlegged stance.
- Grade 4: The kneecap is permanently out of the groove and cannot be repositioned by hand. The leg may appear noticeably crooked, and the dog may avoid using it altogether.
Grades can progress over time. A knee that starts as a Grade 1 in a young dog may worsen to a Grade 2 or 3 as the cartilage in the groove wears down from repeated slipping.
Signs You Might Notice at Home
The hallmark sign is an intermittent skip or hop during a walk or run. Your dog might be trotting along normally, then suddenly lift one back leg for a few strides before dropping it back down and walking fine again. What’s happening in that moment is the kneecap popping out, then the dog extending the leg to let it slide back in.
Other things you might see include reluctance to jump on furniture, stiffness after resting, a crouched or bowlegged posture in the hind legs, or occasional yelping when the knee catches. In higher grades, the lameness becomes more constant. Over time, the repeated displacement wears away cartilage and can lead to arthritis in the joint, even if the luxation itself doesn’t seem painful at first.
When Surgery Is Recommended
Grade 1 luxations that cause no lameness typically don’t need surgery. Grade 2 is a judgment call depending on how often symptoms appear and whether the condition is progressing. Grades 3 and 4 are almost always surgical candidates because the kneecap is out of position often enough to cause cartilage damage, chronic pain, and progressive arthritis.
Surgery usually involves a combination of techniques tailored to the specific anatomy of the dog’s knee. The three most common approaches are: deepening the trochlear groove so the kneecap sits more securely, moving the bony attachment point of the patellar tendon on the shin bone to realign the pull of the quadriceps muscle, and tightening or loosening the soft tissues on either side of the kneecap to rebalance it. A surgeon may use one, two, or all three of these strategies in a single procedure.
The overall prognosis after surgery is good to excellent. However, complication rates range from about 17% to 51% across published studies. The most common complications are the kneecap re-luxating, pin migration or other implant issues, fracture at the site where the bone attachment was moved, and wound healing problems. Re-luxation is more common in smaller dogs and in cases where the underlying bone alignment is significantly abnormal.
What Recovery Looks Like
Recovery requires strict rest and a gradual return to activity over roughly 12 weeks. For the first 10 weeks, your dog should be confined to a crate when unsupervised and restricted to the house, a leash, and the crate when you’re watching them. No running, jumping, or playing during this period.
In the first 24 to 36 hours, you’ll apply an ice pack to the knee for 10 to 15 minutes, four times a day, to control swelling. Once swelling and redness subside, you switch to a warm compress three times daily, followed by gentle range-of-motion exercises: slowly bending and straightening the knee through 10 repetitions. Short leash walks of less than 10 minutes, three times a day, begin after the third day post-surgery. By the 12th week, most dogs have returned to near-full activity.
Managing Without Surgery
For mild cases or dogs that aren’t good surgical candidates, conservative management focuses on keeping the joint comfortable and the surrounding muscles strong. Weight management is the single most important factor. Extra body weight puts more strain on an already unstable knee and accelerates cartilage breakdown.
Joint supplements like glucosamine and chondroitin support cartilage health, and fish oil provides anti-inflammatory omega-3 fatty acids. These won’t fix the structural problem, but they can slow the progression of arthritis. Your vet may also recommend injectable joint-support treatments that help lubricate and protect the cartilage.
Physical therapy and targeted exercises to strengthen the quadriceps and hamstrings can improve stability around the knee. At home, simple adjustments help too: using ramps instead of stairs, providing supportive bedding, and avoiding activities that involve sudden stops or sharp turns. Anti-inflammatory medications can be used during flare-ups to manage pain.
Cost of Surgical Correction
In the United States, luxating patella surgery typically costs between $1,500 and $5,000 per knee, with a national average around $3,300. If both knees need correction, expect roughly double that total. The cost varies based on geographic location, the surgeon’s specialization (board-certified veterinary surgeons tend to charge more), the complexity of the repair, and whether advanced imaging like CT scans is needed for surgical planning. Many pet insurance plans cover the procedure if the condition wasn’t pre-existing at the time of enrollment.