Why Won’t My Dog Put Weight on Their Back Legs?

There is nothing as scary for a dog owner as seeing their beloved pooch suddenly incapable of moving. You may get home only to notice your dog isn’t putting weight on their back legs. Sometimes the cause is clear—they’ve been in a fight. Other times, the cause is not so clear, and your concerns multiply. 

If you see your dog dragging themself around your property, you’ll know it’s serious enough to call the vet before rushing your doggo there for tests and a diagnosis. There are several reasons a dog won’t put weight on their back legs suddenly.  

Why Won’t My Dog Put Weight on Their Back Legs?

Several factors could lead to a dog limping, not putting weight on their back legs at all, or having a weakened hind end. The possible reasons include hip dysplasia, osteoarthritis, dislocation, patellar luxation, osteosarcoma, Lyme disease, inflammation, tendon injuries, muscle trauma, injured paws, and fractures.  

Each of these causes for a limping dog or a dog that won’t put weight on one or both of their back legs has unique causes, but the end result is the same—a dog that’s in pain. 

Hip Dysplasia 

Hip dysplasia is a genetic condition that large breed dogs are especially vulnerable to. German shepherds, Labradors, Dobermans, and other medium to large size dogs frequently develop this condition. 

A dog with this condition has a hip joint that is slightly out of place. Over time, and due to the everyday process of walking or running, their hips start to wear at the socket, causing the hip to become more displaced. Soon, the whole leg will experience weakness, muscles will atrophy, and the dog will become more and more immobile. 

Hip dysplasia often goes hand in hand with osteoarthritis since the ligaments also become damaged and worn out. 

Osteoarthritis 

Older large breed dogs often suffer this progressive condition. When a dog has osteoarthritis, they suffer degeneration and inflammation of the joints. The cartilage pads that line the joints (which eases a dog’s movement) dries up, crumbles, and wears away. Soon the dog suffers pain and excessive rubbing in the joint, which leads to stiffness and loss of motion. 

Dislocation 

Dogs love to play. When they play rough, they often hurt themselves and other dogs hurt them. From an occasional nip or grazed paw, to a broken toe or worse, dogs can easily injure themselves. Dislocation is one such injury that can happen, especially when larger and heavier dogs play with smaller dogs. 

Dislocation of the hip, knees, toes, and even discs in their spinal column may occur from suddenly twisting or being hit by a heavier object traveling at substantial speed. Being hit by a car often results in a dislocation happening. 

Patellar Luxation 

If your dog comes skipping along on three legs for a few strides, not putting any weight on the raised leg, but then the dog walks fine, your dog may have patellar luxation. In plain terms, your dog has a displaced or dislocated patella or kneecap. 

Smaller size dogs often develop this condition, but larger breed dogs may also experience displacement of their kneecaps. The displacement may be the result of trauma such as jumping off a high seat and landing awkwardly or falling during rough play. The ligaments become stretched, and these are no longer able to keep the patella in place as effectively. 

Osteosarcoma 

Like humans, dogs can also suffer the formation of tumors and cancerous growth. With dogs, the cancer often originates in the dog’s bones as opposed to having been transferred there by another source of cancer. 

Cancerous cells weaken the bone structure, affect the surrounding tissue, cause ligaments, muscles, and joints to become inflamed, and result in pain. Soon the dog won’t put weight on their legs. 

Lyme Disease 

Ticks are known carriers of Lyme disease, and while a person or dog may survive this with the aid of antibiotics, this disease can influence the joints. Dogs are known to show stiffening of joints and weakened legs following the onset of Lyme disease. 

Inflammation 

Inflammation can occur as a result of trauma or infection. If your dog has sustained a cut or a puncture mark that you didn’t see, they may have inflammation as a result. This is an immune response where the body creates fluid that puts pressure on the surrounding tissues. Your dog may have inflammation of their back legs, hips, or spine, which can lead to weakness, pain, and stiffness. 

Tendon Injuries 

While dogs are natural athletes, they can also sustain an injury, pulling a tendon or twisting their tendons out of place. This can easily cause them to not apply any pressure to the affected leg. 

Muscle Trauma 

Like tendon injuries, a torn or traumatized muscle may also weaken and be unable to carry the dog’s weight. The dog may choose not to use that muscle, and over time there will be muscle wastage if the dog doesn’t recover quickly. 

Fractures 

Of course, a dog can easily break a leg, hip, or rupture a disc in their spine. These can all cause the dog to be unable to walk on their back legs or put weight on their hind end. Trauma is usually the culprit that causes fractures, but rough play can also lead to fractures. 

Injured Paws

It may seem obvious, but a dog that has a splinter or a thorn in their foot pad can also decide not to walk on that foot. The result could be that the dog won’t put weight on that back leg. 

What to Do If My Dog Won’t Put Weight on Their Back Legs?

If your dog doesn’t put weight on their back legs, examine them gently. Check for signs of injury such as wounds, cuts, and areas that are swollen or hot. If your dog continues to refuse putting weight on their back legs, phone your vet and take your dog for professional assessment. If necessary, your vet may wish to take an X-ray to check for internal damage. Your vet will prescribe the necessary medication and treatment based on their assessment. 

When the cause of the trauma is obvious, such as a thorn sticking out of your dog’s foot pad, you can easily address the situation at home. However, when you can’t find the reason for your dog not wanting to walk normally or refusing to put weight on their back legs, you should consult with your vet. 

Your dog may have suffered a trauma when you weren’t around to see, and it is up to you to ensure they receive the necessary care and treatment. 

How to Treat a Dog Limping on the Back Legs?

Treating your dog that is limping depends on the cause of the limping. Once your vet has established what is causing your dog’s limping or lameness, they will discuss the treatment plan with you. Sometimes, the cause of the limping is curable, but other times, it is more about managing the condition and ensuring your dog is comfortable and not in pain. 

Conditions like hip dysplasia, osteoarthritis, and recurrent patellar luxation will require a management program that involves feeding glucosamine and chondroitin supplements. 

Dislocation, Lyme disease, inflammation, injuries, trauma, and fractures will require assistive treatment to help these conditions heal. 

Finally, osteosarcoma will require cancer management, which could involve chemotherapy, surgery, and possibly, amputation.