Dog Knee Problems and Knee Surgery

How a Dog's Knee Works

A dog's knee is called the stifle. It's the joint on the back leg where the thigh bone (femur) meets the shin bone (tibia), with the kneecap (patella) sliding in a groove at the front of the femur.^6,2 Two cruciate ligaments cross inside the joint and stop the tibia sliding forward and twisting. Two C-shaped pads of cartilage, the menisci, sit between the bones and act as shock absorbers.⁶ The front one, the cranial cruciate ligament, is the equivalent of a person's ACL.

Common Knee Problems in Dogs

• Torn cruciate ligament (CCL or "ACL" tear). One of the most common causes of back-leg lameness in dogs, especially medium and large dogs. The ligament usually weakens slowly over months or years and then tears, often during ordinary activity.^3,10 See torn ACL in dogs.
• Luxating patella (slipping kneecap). The kneecap pops out of its groove, usually toward the inside of the leg. It's most common in small and toy breeds and is usually present from a young age.^2,5 See luxating patella in dogs.
• Meniscal tears. The shock-absorbing cartilage often tears along with a cruciate rupture, which can cause a clicking or popping sound and more pain.^1,11
• Arthritis. Any knee problem that leaves the joint unstable leads to osteoarthritis over time. Surgery slows it down but doesn't completely stop it.^3,12 See arthritis in dogs.
• Osteochondritis dissecans (OCD). A developmental cartilage problem in young, fast-growing large-breed dogs, usually showing between 5 and 9 months of age.¹³
• Fractures and other injuries. Falls and car accidents can break the bones around the knee or tear several ligaments at once. These need urgent care.
• Bone tumors (less common). Osteosarcoma, the most common bone cancer in dogs, often affects the bones just above or below the knee in large and giant breeds.¹⁴ See bone cancer in dogs.

Signs of a Knee Problem

• Limping on a back leg, or holding the leg up, especially after exercise or rest⁶
• A "skip" in the step, where the dog carries the leg for a few strides and then uses it normally; this is typical of a slipping kneecap^5,2
• Sitting with the back leg kicked out to the side (a "lazy sit")⁶
• Difficulty getting up, jumping into the car or climbing stairs⁶
• Swelling or a firm thickening on the inner side of the knee¹
• Muscle loss in the thigh of the affected leg⁶

Limping can also come from the hip, paw or spine, so a vet check is the way to find the source. See why dogs limp.

How Vets Diagnose Knee Problems

Your vet will watch your dog walk and then feel the knee. For a cruciate tear, the main tests are the "drawer" test and the tibial thrust test, which check whether the shin bone slides forward abnormally. Tense or painful dogs may need light sedation for these tests.^3,6 For a slipping kneecap, the vet pushes the kneecap to see whether it moves out of its groove, and grades it from 1 to 4.² Ligaments don't show on X-rays, but X-rays help show swelling, arthritis and bone shape, and are used to plan surgery.^6,3 Sometimes the meniscus is only checked during surgery or with arthroscopy.

Treatment and Surgery Options

The right treatment depends on the problem, its severity, your dog's size and activity level, and your budget.

• Cruciate tears: Surgery is the most reliable option for most dogs, especially medium and large dogs.^1,15 The main operations are TPLO and TTA, which change the angle or shape of the shin bone, and the lateral (extracapsular) suture, which places a strong suture outside the joint.³ Some small dogs improve with rest, weight control, pain relief and rehabilitation.^16,6
• Luxating patella: Mild (grade 1) cases are often just monitored. Surgery is usually recommended for grade 2 and above, especially when the dog is lame or the condition is getting worse. The surgeon deepens the groove and moves the bony attachment of the kneecap tendon so the kneecap stays in place.^2,5
• All knee problems: Keeping your dog lean is one of the most helpful things you can do, since heavier dogs are at higher risk.^7,6 Vet-prescribed pain relief, controlled exercise and physical rehabilitation can also help, both with and without surgery.

After most knee surgeries, dogs need about 6 to 12 weeks of restricted activity, with leash walks only, followed by a gradual return to normal exercise.^17,10,18 See hip surgery in dogs for joint surgery of the hip.

Frequently Asked Questions

What is the most common knee injury in dogs?

A torn cranial cruciate ligament, the dog equivalent of a torn ACL, is the most common in medium and large dogs. A slipping kneecap is most common in small breeds.

How do I know if my dog hurt its knee?

Limping on a back leg, toe-touching, sitting with the leg out to the side, a skipping gait, or swelling around the knee are common signs.

Can a dog's knee injury heal on its own?

A torn cruciate ligament doesn't heal back together. Some small dogs improve with rest and rehab, but larger dogs usually do better with surgery.

How much does dog knee surgery cost?

In the US, cruciate surgery estimates range from about $3,800 to $5,000 per knee (2017–2021 figures) to $6,000 to $10,000 in a 2026 insurer guide. Kneecap surgery is often quoted at $1,000 to $5,000 per leg.

How long does a dog take to recover from knee surgery?

Most dogs need about 6 to 12 weeks of restricted activity, and full recovery can take several months or longer.

Can a dog walk with a bad knee?

Many dogs still walk, often with a limp, but walking on an unstable knee speeds up arthritis and can damage the meniscus.

Is my dog too old for knee surgery?

Age alone isn't a reason to avoid surgery. Your vet will look at your dog's overall health, weight and other conditions.