Luxating Patella in Dogs: Grades, Symptoms and Treatment

What Is a Luxating Patella?

The kneecap (patella) normally glides up and down in a groove at the end of the thigh bone. In a luxating patella, it rides out of that groove, usually when the knee bends.² Medial luxation, where the kneecap slips toward the inside of the leg, is far more common. Lateral luxation, toward the outside, is less common and seen relatively more often in large breeds.^1,3 Most cases are developmental, caused by the shape and alignment of the bones and muscles of the leg, though trauma can occasionally cause it.^3,1 For an overview of other knee conditions, see dog knee problems.

Luxating Patella Grades

Vets use a standard four-grade system:¹

• Grade 1: the kneecap can be pushed out by hand but goes back into place on its own.
• Grade 2: the kneecap slips out on its own or when pushed, and goes back when the leg is straightened or it's pushed back.
• Grade 3: the kneecap is out of place most of the time but can be pushed back in; lameness is consistent and bone changes are visible.
• Grade 4: the kneecap is permanently out of place and can't be pushed back.

The grade can get worse over time, for example from grade 2 to grade 3, as the edges of the groove wear down.^9,1

Symptoms of a Luxating Patella

• A sudden "skip" or hop, where the dog carries a back leg for a few steps and then uses it normally^2,1
• Kicking or stretching the leg out behind, which can pop the kneecap back in¹
• Lameness that becomes more frequent, and eventually constant, as the condition progresses²
• Bow-legged or knock-kneed back legs in more severe cases^5,1
• Signs usually start before 1 year of age, though many dogs aren't diagnosed until later^1,7

Both knees are often affected.^10,5

Which Dogs Get It?

Small and toy breeds are most at risk. In a large UK study, Pomeranians, Chihuahuas, Yorkshire Terriers and French Bulldogs had the highest odds, followed by Pugs, Lhasa Apsos, Bichon Frises, Bulldogs and Cavalier King Charles Spaniels.⁷ Boston Terriers and Miniature Poodles are also commonly affected.² Among large breeds, Shar Peis, Flat-Coated Retrievers, Akitas and Great Pyrenees are predisposed.² In the UK study, females had 1.3 times the odds of males and neutered dogs 2.4 times the odds of intact dogs.⁷

Medial patellar luxation is considered inherited, so affected dogs shouldn't be bred. The Orthopedic Foundation for Animals runs a patella registry for dogs 12 months and older.¹⁰

Treatment: With and Without Surgery

Without surgery: Dogs with grade 1, and some with grade 2 and no lameness, are often managed with weight control, regular moderate exercise to keep the thigh muscles strong, and vet-prescribed pain relief during flare-ups.^1,9 This doesn't correct the shape of the leg, so the condition can still progress and should be rechecked.¹ In the UK primary-care study, more dogs were managed medically (39%) than surgically (13%).⁷

Surgery: Surgery is usually recommended for grade 2 and above, especially for dogs with ongoing lameness or a condition that is getting worse.^1,2 Common procedures include:^1,2

• Deepening the groove the kneecap sits in (trochleoplasty)
• Moving the bony point where the kneecap tendon attaches to the shin bone (tibial tuberosity transposition)
• Tightening or loosening the tissues on either side of the kneecap
• Straightening a bowed thigh bone in severe cases

Results are best when surgery is done before arthritis develops, since arthritis can't be reversed.⁵ Complications are more likely in higher grades and in dogs 20 kg (44 lb) or heavier.⁸ In Pomeranians, the kneecap slipped again after surgery in about 11% of grade 3 cases and 36% of grade 4 cases, while grade 2 cases did very well.⁹ If your dog also has a torn cruciate ligament, both problems are usually addressed, often in the same operation.^1,11 See torn ACL in dogs.

How Much Does Luxating Patella Surgery Cost?

In the US, luxating patella surgery is often quoted at about $1,000 to $5,000 per leg, depending on the grade, the procedures needed, the dog's size and the region.¹² Referral and complex cases cost more; one UK university referral hospital lists simple cases from about £4,300 to £5,350 per knee (2026, including VAT).¹¹ Ask for a written estimate that includes X-rays, pain medicine and recheck visits.

Recovery After Surgery

Expect about 6 to 8 weeks of restricted activity, with short leash walks only, and follow-up X-rays at around 6 to 8 weeks.⁹ Activity is then increased gradually. Physical rehabilitation can help rebuild muscle. If both knees need surgery, your surgeon may do them one at a time, usually once the first knee has recovered.

See arthritis in dogs and why dogs limp.

Frequently Asked Questions

Can a dog live with a luxating patella?

Yes. Many dogs with grade 1 or mild grade 2 live normal lives. Higher grades often need surgery to reduce pain and slow arthritis.

Can a luxating patella heal on its own?

No. The underlying shape of the leg doesn't correct itself, but mild cases may never need treatment.

Is walking good for a dog with a luxating patella?

Regular, moderate leash walks help keep the thigh muscles strong. Avoid lots of jumping and sudden twisting.

Does a luxating patella get worse with age?

It can. The grade may increase over time, and arthritis can develop in the joint.

What happens if a luxating patella is left untreated?

Mild cases may stay stable. More severe cases can lead to constant lameness, arthritis and a higher risk of a torn cruciate ligament.

How much does luxating patella surgery cost?

In the US, often about $1,000 to $5,000 per leg, depending on the grade, the dog's size and the region.

Is luxating patella surgery worth it?

For dogs with grade 2 or higher and ongoing lameness, usually yes. Over 90% of owners are satisfied with the result.

Is a luxating patella painful for dogs?

Often not at first, but it can become painful as the grade increases and arthritis develops.