Knee problems in dogs

Written by Susan McCullough Reviewed by Kristin Westafer, DVM

Overview

Picture a large, middle-aged dog (maybe a Rottweiler) chasing a cat, a rabbit or other similar quarry. Suddenly the dog yelps, pulls up short and lifts her hind leg, clearly unable to put any weight on it, and needs to be carried home. Or here's another picture: a small-breed puppy, such as a Yorkshire Terrier, tears around his owner's backyard but suddenly halts, squeals and lifts his rear leg as though he's getting ready to urinate. Unlike the Rottie, however, the Yorkie hops around for a few steps, then resumes his backyard scampering. All seems well – until a few days later, when the same thing happens again.

Both dogs are having problems with their knees. The Rottweiler likely has a ruptured cruciate ligament, the repair of which is currently the most common surgical procedure performed on injured dogs. The Yorkie has a luxating patella – a very common condition among toy breeds that also occurs among short-legged breeds such as Dachshunds. Together, these two conditions account for the vast majority of canine knee problems.

Symptoms

Sudden pain while running
Lifting of affected leg off the ground
Inability to put weight on affected leg
Pain when moving
Intermittent lameness
Bunny hopping gait
Swollen knee joint
Shifting leg lameness

Prevention

Owners can't prevent their individual dogs from having luxating patellas, because the condition has a genetic component. However, a prospective buyer of a toy or short-legged puppy should ask the breeder whether any dogs in the puppy's pedigree have had a luxating patella. If any have, the buyer should reconsider buying that particular puppy.

Keeping your dog trim, particularly if he is a large breed such as an Akita, American Staffordshire Terrier, Golden Retriever, Chesapeake Bay Retriever, Labrador Retriever, Neapolitan Mastiff, Newfoundland, Rottweiler or St. Bernard, may help reduce the risk of cruciate ligament rupture.

Treatment

A luxating patella means that the dog's kneecap is dislocated. Instead moving smoothly within the groove at the bottom of the upper leg bone, the kneecap pops out of the groove, usually to the inside part of the leg. Many experts believe the toy dog's very small legs cause the kneecap to pop. And because the condition usually occurs within the first year of the dog's life, researchers believe that genetics are involved.

Some patella luxations are more severe than others. With a mild luxation, a veterinarian can easily push the kneecap back into place, and may prescribe restricting exercise, monitoring the dog's activities and giving him aspirin when necessary. More severe cases require surgery to return the kneecap to its proper position. Such surgery can cost between $1,000 and $1,500 per knee.

Unlike luxating patellas, a dog's cruciate ligament ruptures due to wear and tear, which is why this condition occurs more often in dogs that are middle-aged or older. The ligaments hold the bones and cartilage of the knee in place so that the knee bends properly. When a ligament ruptures, or tears, the knee can no longer bend correctly, and surgery is the only way to repair the ligament. Such surgery usually costs about $3,000 per knee.

Post-treatment

After surgery for a luxating patella, the patient won't be able to run or jump for three to eight weeks, but easy walking or swimming is recommended. The post-surgical cruciate ligament rupture patient probably won't put any weight on the affected leg for 10 days to 2 weeks. He'll need to limit his exercise to slow walking or short periods of swimming for about 8 weeks after the surgery.