If your dog drags the top of his paw on the ground when moving, he's knuckling. Causes of canine paw knuckling range from minor to serious, from something your dog might outgrow to a disease that will eventually kill him. Conditions causing knuckling affect all ages. Get your paw-knuckling dog to the vet for diagnosis and treatment.
Carpal Flexural Deformity
Puppies might start knuckling over as they undergo growth spurts. While young dogs of any size might be affected, it's particularly common in large breeds. In carpal flexural deformity, generally seen in puppies under the age of 4 months, the animal's wrists hyperflex, or bulge forward. In most cases, treatment isn't necessary -- the puppy's wrists will straighten out within a few weeks. Your vet can recommend the right diet for your puppy, as excessive protein can cause the condition in large breeds. Until your puppy recovers, keep him relatively quiet and avoid exercising him or placing him in situations challenging his mobility, such as frequently going up and down stairs.
If your dog suddenly start knuckling over, carefully check his paws. He could have a thorn or other sharp object imbedded in his foot, causing pain when he walks. If it's hot out, he might have burned his footpads on pavement. Other possibilities include insect bites, or broken claws or toes. If you don't see an obvious cause, and the situation doesn't resolve itself within a day, take your dog to the vet.
Intervertebral Disc Disease
Intervertebral disc disease occurs when the shock-absorbing discs in a dog's spinal column start degenerating, generally a result of age. Although symptoms of IVDD vary, most affected dogs begin stumbling, walking oddly or knuckling paws. While mild cases might be treated with steroids and anti-inflammatories, more severe cases require surgery. Your vet can recommend a board-certified veterinary neurologist to perform the operation if surgery is necessary.
While any dog can experience a fibrocartilagenous embolism, this spinal condition more often occurs in big canines. It usually appears as a result of exercise trauma, with the knuckling-under of a rear paw a key sign. Fibrocartilagenous embolism occurs when a small piece of an intervertebral disc detaches and gets into a blood vessel, causing an embolism or blood clot. Dogs might or not might get better, but they usually do not get worse.
Older dogs who exhibit paw knuckling and dragging could be suffering from arthritis, or this lameness could be signs of degenerative myelopathy, or loss of myelin, a white matter sheathing the spinal cord. The dog's rear paws knuckle, especially when he tries to turn. Other signs include difficulty rising and frequent falling. While the disease is not painful, it is progressive, and most dogs are eventually humanely euthanized.
By Jane Meggitt
VCA Animal Hospitals: Degenerative Myelopathy in Dogs
Canadian Veterinary Journal: Canine Carpal Conundrums
Martha's Vineyard Times: Visiting Veterinarian: Tincture of Time
Veterinary Specialists and Emergency Service: Understanding Intervertebral Disc Disease in Dogs
WebDVM: Fibrocartilagenous Embolism
PetMD: Swollen Paws in Dogs
About the Author
Jane Meggitt has been a writer for more than 20 years. In addition to reporting for a major newspaper chain, she has been published in "Horse News," "Suburban Classic," "Hoof Beats," "Equine Journal" and other publications. She has a Bachelor of Arts in English from New York University and an Associate of Arts from the American Academy of Dramatics Arts, New York City.