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15 Reasons Your Old Dog’s Back Legs Are Collapsing

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“Doctor T., my old dog’s back legs are collapsing! She falls when she tries to walk. What’s causing my dog’s back leg weakness and what can we do about it?” This is a complaint I’ve heard many times in the vet clinic from dog owners facing a change in their pet’s mobility. 

The most common causes for a dog’s back leg weakness are osteoarthritis, intervertebral disc disease, lumbosacral instability and degenerative myelopathy. And some dogs have more than one issue contributing to their hind leg weakness.

You can do to help your dog maintain his quality of life despite his hind end weakness. Skip to the second half of the article if you’re looking for solutions.

There are many possible causes at play when you see a dog’s back legs collapsing. I’ve listed some of them below but I’m only going to cover the more common ones in detail.

15 Causes of Hind Leg Weakness and Collapse in Dogs

CauseCommon?Other Symptoms
OsteoarthritisVery CommonCrackling joints, limping, stiff gait
Degenerative MyelopathyCommon in some breedsUrinary and/or fecal incontinence
Lumbosacral InstabilityCommon in some breedsPain in the lower back, tail pain, incontinence
Intervertebral Disc DiseaseCommonPain in spine anywhere from last few ribs to tail
Blood LossUncommonPale gums, rapid breathing even at rest, palpable abdominal tumor
CancerCommonDepends on the location of cancer–palpable tumor, difficulty breathing
Chronic AnemiaUncommonLethargy, rapid breathing even at rest, pale gums, blood or tarry appearance to stools
Diabetes MellitusUncommonWeight loss despite increased appetite, thirst and urination
DiscospondylitisUncommonPain anywhere in the spine, sometimes urinary symptoms, fever
Fibrocartilagenous EmbolusUncommonDog has trouble walking all of a sudden, back legs weakness/paralysis, may cry out but the pain only lasts a few minutes
Heart DiseaseCommon in some breedsRapid breathing, pale or bluish gums and tongue, coughing
Kidney DiseaseCommonIncreased thirst and urination, poor appetite, weight loss
Liver Disease CommonPalpably enlarged liver, fluid distending the abdomen, jaundice of skin and whites of eyes, dark yellow color to stool and urine, vomiting, diarrhea
Myasthenia GravisUncommonWeakness and collapsing is worse after exercise, regurgitation of food without typical retching associated with vomiting
Tick ParalysisCommon in some geographic areasWeakness usually starts in hind limbs and progresses to affect all four limbs, presence of an attached tick

It’s hard for your vet to know which one of these problems is causing a dog’s back legs weakness without diagnostic testing. Radiographs (x-rays) are required in almost every case to make a diagnosis. Read on to find out more about each problem and treatment that can strengthen your old dog’s hind legs and help regain his mobility. 

Symptoms

Unless your is dog suddenly weak in his back legs, it might not be obvious that he has a problem. Back leg weakness in older dogs often comes on gradually. Some of the things that indicate a problem:

  • Stumbling or tripping
  • Drags back feet when walking
  • Slower going up stairs
  • Jumping on furniture less
  • Slow getting up from lying down
  • Doesn’t want to run as much as before
  • Reluctant to jump into the car
  • Worn down toenails on back feet from scuffing
  • Thigh/hip muscle atrophy
  • Change in tail position
  • Falling more often
  • Back legs become spastic/ involuntary kicking
  • Takes smaller steps with back feet
woman walking outdoors at sunset with two large dogs (old dog's back legs collapsing)
Large breed dogs experience weak/wobbly hind legs more often than small breeds.

Now let’s discuss the top four most common causes of weak, wobbly, splayed out, dragging, slipping, collapsing dog hind legs…

1. Arthritis: Very Common Cause of Weak Hind Legs

At least 25% of dogs will be diagnosed with arthritis/osteoarthritis (OA) during their lifetime and up to 60% have evidence of OA on x-rays (2). OA happens when the cartilage in joints breaks down which leads to inflammation and pain. OA can affect any joint, but the large joints in the front and hind limbs are frequently affected. 

Large breed dogs tend to get osteoarthritis at an earlier age than small breed dogs. Certain breeds have a higher likelihood of inheriting orthopedic abnormalities like hip dysplasia. My friend over at WorldofDogz.com has a great article about hip dysplasia in German Shepherds but the advice applies to all breeds.

Breeds Affected

  • German Shepherd
  • Labrador Retriever
  • Golden Retriever
  • Rottweiler
  • Mastiff

Affected dogs with advanced hip or knee arthritis are likely to have weak hind legs, trouble walking and sometimes can’t get up on their back legs without help. Pain leads to decreased activity, which leads to loss of muscle mass and even more hind end weakness. 

Dogs with arthritis may not show obvious signs of pain, but you can see they are painful by the way they stand, the way they walk and the way they have trouble getting up and down from a lying position. They tend to be very stiff-gaited when they first stand up after lying down for a while, but they become less stiff as they move around. You may hear “crackling” sounds when you manually manipulate an affected dog’s knee or hip. 

All breeds of dogs, including mixed breeds, are affected by OA. The older a dog is, the more likely they are to have some degree of osteoarthritis. 

Treatment

Treatment for canine arthritis has come a long way in the last few decades. We have many treatment options from oral medications to stem cell therapy to acupuncture and physical therapy. The basic supplements I recommend for dogs with arthritis are UCII (undenatured collagen), fish oil, and possibly turmeric. I have an entire article on how you can help your arthritic dog even without going to see a veterinarian.

The key points to remember in canine osteoarthritis are to keep their weight down, keep them moving, and treat their pain. Most dogs with arthritis can live a pretty normal life with diligent monitoring and appropriate medical care. 

Read my article about how to help dogs with arthritis: How to Help Your Arthritic Dog at Home.

2. Degenerative Myelopathy

Degenerative myelopathy (DM) is an inherited abnormality of the nervous system that causes weak back legs in older dogs. Puppies inherit a genetic mutation from their parents that puts them at risk for developing DM. (3).

DM has been compared to Lou Gehrig’s disease in humans (1). DM also occurs in mixed breed dogs. A dog owner usually notice occasional dragging of back feet that progresses to trouble walking due to back leg weakness and collapsing back legs.

Breeds Affected

  • German Shepherds
  • Pembroke and Cardigan Welsh Corgis
  • Standard Poodles
  • Pugs
  • Collies
  • Boxers

A diagnosis of DM is based on clinical symptoms, a vet exam, blood testing, and radiographs (x-rays). In some cases, electromyogram (muscle testing), spinal taps and CT/MRI help confirm the diagnosis. In real-world vet practice, ruling out other causes of hind end weakness (ataxia) is the mainstay of diagnosing DM.

Dogs 8 years and older are more likely to show symptoms of DM. Early signs include difficulty jumping, weakness in the dog’s back legs including collapsing, stumbling, splaying out, slipping, “crossing-over” of rear feet, worn down toenails and abrasions on the feet from scuffing. Degenerative myelopathy is not known to cause pain and most dogs don’t seem distressed in the early stages of the condition.

In the early stages, degenerative myelopathy may be difficult to differentiate from osteoarthritis and disc disease. Inflammatory diseases including bacterial infection, fungal infection and cancer affecting the dog’s spinal cord cause symptoms very similar to DM.

white German Shepherd dog carrying a toy in a grassy yard
German Shepherds are affected by several diseases that weaken the hind legs.

Treatment

Tragically, there are no proven effective treatments for DM at this time. A regimen of nutritional supplements, special diet, exercise, and various alternative therapies (acupuncture, cold laser, physical therapy, homeopathy) may slow the progression of the disease. Dr. Roger Clemmons, a vet neurologist at the University of Florida, has an interesting web site with his recommendations for treating DM.

The earlier you recognize the signs of DM, the better the chance of stalling the progression of back leg weakness. The long-term prognosis is poor. Most dogs lose the ability to walk within 6-12 months of diagnosis. 

Urination and defecation difficulties are major considerations in caring for dogs with degenerative myelopathy. Difficulties dealing with these challenges lead most dog owners to have their affected pets euthanized within 18 months. Smaller breeds are more easily managed for longer periods of time.

Dog's back foot with two middle toenails worn down due to weak back legs.
Common symptom of back leg weakness… a dog’s back paw with worn nails

3. Lumbosacral Instability

Also known as cauda equina syndrome, lumbosacral stenosis, lumbosacral instability, this problem affects the space between the last vertebrae and the sacrum. If you’re looking at a dog, the lumbosacral (LS) area is in his lower back, just behind the two pelvic bones that stand out in that area. Instability in this area leads to abnormal movement of the bones and pinched nerves. 

Lumbosacral disease symptoms depend on which nerves are affected. Some dogs have weak back legs and shaking (from pain) while others show limping and back legs collapsing, and some have urinary and fecal incontinence, while some have decreased tone and sensation to their tail. Dogs with LS instability often cry out or flinch when touched around the low back, tail and back legs. 

Breeds Affected

  • Airedale
  • Boxer
  • German Shepherds
  • Golden Retriever
  • Great Dane
  • Labrador Retriever
X-ray of a dog's lower back with new bone formation at the lumbosacral junction.
Radiograph of a dog with lumbosacral disease

Treatment

Treatment for LS trouble is often a matter of pain management and avoidance of activities like running and jumping. Surgery can help stabilize the lumbosacral joint, but due to the advanced age of most affected dogs and the chronic changes present, surgery is not as common as medical treatment. 

Steroids may be used for dogs with acute, severe pain and weakness, but non-steroidal anti-inflammatory drugs (NSAIDs) are used for long-term management. Acupuncture and cold laser therapy may relieve pain during flare-ups.

One of my dogs (a German Shepherd mix) has suffered from LS disease for over five years. She has stretches of time where she is quite comfortable thanks to nutritional supplements, steady moderate exercise, NSAIDs and pain medicines. Every couple of years she has a bad flare of pain and it can take months for her to return to normal. 

I go out of my way to keep her from jumping and running since those activities are likely to bother her LS disease. She’s a healthy dog in every other way, it’s just something we have to manage. 

4. Intervertebral Disc Disease 

Intervertebral disc disease (IVDD) happens when the disc cushion between the bones of the spine breaks down and presses on nerves branching off the spinal cord. In dogs, the most common locations for IVDD are the neck and the mid-to-lower back or thoracolumbar area. Dogs with IVDD in the thoracolumbar area sometimes have weak back legs and panting due to pain early in the disease. In severe cases, you’ll see an old dog’s back legs collapsing or becoming so weak they can’t stand at all.

IVDD is common in adult dogs of all ages, but older dogs may be more severely affected.  

Breeds Affected

  • American Cocker Spaniel
  • Bassett Hound
  • Beagle
  • Corgi
  • Dachshund
  • German Shepherd
  • Shih Tzu

Radiographs can sometimes identify IVDD lesions, but special imaging like MRI or myelograms is needed to know for sure. Special imaging is usually done by a vet specialist and requires the dog to be under anesthesia

Dog's back legs with one foot knuckled under and muscle atrophy in the thigh area.
Hallmarks of chronic neurologic problems that are the cause of an old dog’s back legs collapsing.

Treatment

IVDD treatment depends on the severity of the symptoms. For mildly affected dogs with pain only and no hind leg weakness, strict rest and anti-inflammatories bring improvement within a week or two.

Dogs who are stumbling, cannot stand, or have significant hind end weakness may improve with rest and medication prescribed by a vet. It can take dogs like this weeks to months to recover. Your vet will advise you that dogs with paralysis of their hind limbs are good candidates for surgery.

You can read much more about IVDD symptoms, treatment and prognosis in my article on the topic. 

Read all about IVDD in dogs in my article: IVDD in Dogs: Symptoms and How You Can Help.

Other Common Causes for Dogs’ Back Legs Collapsing

Other diseases can cause generalized weakness which is often first noticed in the rear legs. Many serious health problems lead to weakness that can cause a dog’s back legs to collapse, but there are usually other symptoms, too. 

  • Anemia (low red blood cell count)-lack of oxygen causes generalized weakness.
  • Blood loss (internal bleeding from gastric ulcer or tumor)-lack of oxygen and low blood pressure causes weakness.
  • Cancer-often comes with anemia or metabolic toxins that cause generalized weakness.
  • Diabetes mellitus-poorly controlled blood glucose means cells aren’t getting fuel to function, electrolyte imbalances lead to weakness.
  • Heart failure-poor oxygenation causes generalized weakness.
  • Kidney disease-anemia, electrolyte imbalances, dehydration, toxin buildup lead to weakness.
  • Liver disease-anemia, dehydration and toxin buildup lead to weakness.
Two Weimaraner dogs playing outdoors
Weimaraners are susceptible to pericardial disease that can cause hind leg weakness.

Uncommon Causes of Rear Leg Collapse in Dogs

Among the less common diseases that lead to young or older dogs’ back legs giving out are tick paralysis, myasthenia gravis and discospondylitis. 

  • Tick paralysis is caused by the toxic effects of an attached tick. It is more common in certain parts of the country. The good news about this one is that simply removing the tick helps the dog recover.
  • Fibrocartilagenous embolus, sometimes called spinal stroke, is relatively uncommon. This problem arises when a small piece of tissue breaks free from one body area and gets lodged in the blood supply to the spinal cord. Without adequate blood flow, nerve impulses can’t be conducted to the hind limbs.
  • Myasthenia gravis occurs in younger dogs from a genetic mutation. In older dogs, MG is an autoimmune problem that disrupts the message from the nerve to the muscle. Dogs with myasthenia gravis experience muscle weakness that is worse after exercise. It’s not uncommon for senior dogs with myasthenia gravis to have a tumor somewhere in their body, the most common being thymoma. There is a treatment for MG, but the long-term prognosis is guarded. 
  • Discospondylitis happens when the intervertebral disc and end of spinal vertebrae become inflamed from an infection. Bacteria and fungi are the usual causes of infection. This disease can often be tentatively diagnosed with an x-ray of the spine, but cultures are needed to confirm the cause. Once the cause of the infection is identified, the appropriate antibacterial or antifungal medication helps the infected area return to normal, but it can take weeks. 

What to Do If Your Dog’s Back Legs Are Giving Out

Maybe your dog can still walk normally but has trouble with his back legs slipping out from under him. It’s worse when dogs like this try to stand or walk on slick floors. He winds up struggling with his back legs splayed out and trying to get a grip. 

The first thing you can do is install inexpensive carpet runners throughout your house. Make sure to put one anywhere your dog usually walks. Some home improvement stores sell carpet runners by the yard from rolls.

I really like these carpet runners from Amazon because they come in different colors and sizes and have a non-slip back built-in. 

Several gray runner rugs on a slippery tile floor to help dogs with weak back legs walk more easily.
I use multiple carpet runners on my tile floor to keep my old dogs back legs from slipping

Some of my clients have tried devices put directly on the dog’s paw to increase traction. You have to be careful with this because if you have to tighten anything around the foot it can cut off circulation and cause serious injuries. For that reason, soft socks or booties are popular. They work alright when they’re on the foot, but most people report they have a hard time getting them to stay on the foot when their dog is collapsing or dragging her feet. 

You might check out these soft plastic caps for your dog’s toenails that help him get a better grip. The main problem you will have is 1) some dogs hate having their toes handled, and 2) the caps may fall off prematurely. I don’t think I would bother trying a paw “friction” product made to glue some grippy material to the actual paw pad. I think it would be too hard for most people to put on and again, some dogs really hate having their feet messed with!

Black standard poodle running in grass
Dogs who hike or stay outdoors a lot can get tick paralysis.

Dog’s Back Legs Collapsing and Incontinent?

It’s pretty alarming to watch your dog’s back legs giving out more and more as time passes. Dogs often reach the point that they’re passing stool and urine in the house. Many clients report their dog is very upset by it, too.

Before you panic, first, figure out if he just can’t get outside fast enough to potty there. If that’s the case, more pain meds or better pain treatments. Make sure you help him get outside frequently throughout the day even if he doesn’t act like he needs to go. 

If urine and/or stool are dribbling out while your dog is walking, and he seems unaware of it, that’s more likely true incontinence.

In either case, you can try using diapers with a hole cut for his tail, or purchase special diapers made for dogs. You need to change these frequently because just like babies, dogs will get dermatitis from having a soiled diaper on for too long. 

Your Dog Might Love Her Own Wheelchair

Some of my clients have had great experiences with wheeled carts like the ones made by Walkin’ Wheels. Dog “wheelchairs” are made to support a dog’s rear legs so they can walk normally with their front legs. Most dogs adapt well to these and seem perfectly happy to zoom around with the help of their wheels! 

Some dogs prefer to go without a wheelchair, especially indoors. For them, a “drag bag” can help protect the back half of their body from abrasions. These work better for dogs under 25 pounds or so, but it doesn’t hurt to give it a try with larger dogs. 

The best device I’ve seen for dogs who can still walk but need help getting up or going up stairs, etc. is a vest that has a handle on the top. Dogs can wear the vest most of the time and you can easily grab the handle to give a little extra help when needed. 

How to Strengthen an Old Dog’s Hind Legs

Yes, it is possible to strengthen the back legs of a senior dog! You’ll want to make sure his pain is adequately managed before starting on a rehabilitation regime. I recommend you find a veterinarian trained in physical therapy and rehabilitation for the best outcome (link to find one), but you can get started on your own.

How to strengthen your old dog’s hind legs:

  1. Slow walks daily. Don’t go so long it makes your dog sore the next day. 
  2. Swimming is good exercise as long as the season is right and your dog is willing. Don’t overdo it. Some dogs get so excited about swimming they end up in a lot of pain later. 
  3. Stretching. Move your dog’s limbs through their normal range of motion while she’s laying down to keep her limber. Check out this awesome book on how to stretch your dog: The Healthy Way to Stretch Your Dog. My dogs love it!

Related Posts:

References

  1. Awano, T., Johnson, G. S., Wade, C. M., Katz, M. L., Johnson, G. C., Taylor, J. F., … & March, P. A. (2009). Genome-wide association analysis reveals a SOD1 mutation in canine degenerative myelopathy that resembles amyotrophic lateral sclerosis. Proceedings of the National Academy of Sciences, 106(8), 2794-2799.
  2. Bland, S. D. (2015). Canine osteoarthritis and treatments: a review. Veterinary Science Development.
  3. Coates JR and Wininger FA: Canine Degenerative Myelopathy. Vet Clin North Am Small Anim Pract 2010 Vol 40 pp. 929-50.
  4. Shelton, G. D., Schule, A., & Kass, P. H. (1997). Risk factors for acquired myasthenia gravis in dogs: 1,154 cases (1991-1995). Journal of the American Veterinary Medical Association, 211(11), 1428-1431.

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Last update on 2021-10-17 / Affiliate links / Images from Amazon Product Advertising API