Knuckling: What is it, what causes it, and what can be done about it?

“Knuckling” and “knuckling over” are terms that refer to loss of proprioception in dogs. Knuckling occurs when a dog’s leg and/or paw fail to flex properly when walking. This condition may first appear as dragging the top of the paw across the ground and progress to walking on the knuckles, rather than the pads of the foot.

Causes of knuckling include spinal trauma as a result of vehicular accidents, intervertebral disc disease, fibrocartilaginous embolisms (FCE) and spinal tumors. Knuckling can also be caused by degenerative myelopathy (DM) and, on occasion, inflammatory or infectious etiologies. Lastly, it can be caused by general hind limb weakness that often comes with age.

Knuckling can result in a loss of balance, which can lead to painful falls. Frequent knuckling, or dragging of the paws, can also lead to abrasions and open sores, which may become infected or ulcerated. Importantly, knuckling diminishes a dog’s enjoyment in walking which, in turn, reduces the quality of the dog’s life.

Introducing the Canine Mobility Anti-Knuckling Device™

The Canine Mobility Anti-Knuckling Device (AKD) is a therapy tool for dogs suffering from knuckling caused by various forms of spinal trauma. It uses an adjustable elastic cord secured to a material paw strap at one end, and a dog harness at the other. The paw strap consists of a loop that fits around the dog’s two innermost toes (Phalanges) and another loop that fits around the dog’s lower leg bones (Metatarsus).

The unique design of the AKD differs from other available products in that it brings the affected leg forward while simultaneously lifting the toes, effectively reducing or eliminating knuckling. The device has proven to be effective, comfortable, and easy to use.

Is your dog knuckling? We may have the solution. Click here for instructions on how to measure your dog.

Kirby is a 14-year-old Labrador Retriever who fell on the ice several times in February, 2014 and was favoring his left rear leg. An MRI showed spondylosis at T13-L1, bridging and multiple disc protrusions, and osteoarthritis of some facets, specifically L3-4. Kirby knuckled occasionally but could still go on walks. He subsequently received underwater treadmill and laser therapy and acupuncture for 2 years.

In early March, 2016 Kirby’s back legs gave out and he was only able to walk short distances. There was moderate knuckling and/or dragging of his hind legs on these walks. His treatments in the underwater treadmill were discontinued.

Kirby began using bilateral AKDs in April 2016 and was able to resume therapy in the underwater treadmill.  As shown in this video at Veterinary Orthopedics and Sports Medicine, he started with short sessions with increases in the number of minutes on each weekly visit.

Klaire is a 6-year-old Labrador Retriever who suffered a fibrocartilaginous embolism (FCE). She was completely paralyzed from the waist down for several weeks. After extensive rehab, she regained mobility in her right hind leg but she had lost virtually all use of her left hind leg.

This video shows Klaire in two months after her FCE. She is shown first walking first with a RuffWear boot on her left hind paw, and then with the AKD affixed to the boot. The next video shows Klaire nine months post FCE using the AKD without the boot. The AKD has enabled her to walk again, and in doing so has strengthened her good leg and assisted in rebuilding strength in her weakened left leg. It has also significantly improved the quality of her life.

Reilly is a 13-year-old Irish Setter with arthritis and intervertebral disc disease and is 15 months post L4-S1 dorsal laminectomy. His knuckling began approximately two months after his surgery when he was able to resume his daily walks. It was heartbreaking to see something he enjoyed and looked forward to be the source of continued pain.

The effects of Reilly’s knuckling are shown in this video. He is also shown in this video, using the AKD on his right hind leg. He had been using the AKD for one year at the time of this video. As a result of his use of the AKD, the muscles that had atrophied during the course of his recovery from surgery were strengthened and he was able to resume walking with a normal gait.

Gus is a nine-year-old Rhodesian Ridgeback who has been diagnosed with Degenerative Myelopathy (DM) and intervertebral disc disease (L7-S1). With great effort he is still able to walk on his own although he knuckles on both rear paws and has developed “wear sites” on his toes. He continued to knuckle while using an Eddies Wheels and he experienced episodes of bleeding of the nails and on the tops of his paws.

Gus is shown in this video using his Eddies Wheels cart. The cart takes some of the weight off his hind legs and allows him to continue walking with all four legs. He has, however, continued to have problems knuckling and dragging his hind legs and has experienced episodes of bleeding of the nails and on the tops of his paws.

In this video, Gus has bilateral AKDs affixed to his Eddie’s Wheels cart to prevent him from knuckling. The shock cords are attached to the cart’s frame on either side of Gus’s shoulders instead of the typical arrangement in which they are connected to a harness. He had been using the AKDs for one month at the time of this video and a noticeable reduction in the frequency of his knuckling can be seen.