5 Causes For Sudden Limping In The Back Leg Of Dogs

If your dog starts limping suddenly on its back leg, it can be cause for concern. There are a few different things that could be causing the issue, and it's important to get to the bottom of it as soon as possible. There are of course many other reasons for a dog to limp in its back leg but here we will address the most common and concerning causes. Below are 5 of the most common causes of sudden limping in the back leg of dogs.

1. Ruptured ACL (Anterior cruciate ligament)

The most common cause of sudden limping of a back leg in dogs is a ruptured cruciate ligament (ACL). The ACL in dogs is located in the knee, and when it is ruptured, it causes the dog to lose stability in the joint. Dogs will typically have a "toe-touching" lameness that is present at all times. This can be very painful for your dog, and if left untreated, can lead to further damage to the joint such as a meniscal tear.

Fortunately, a torn ACL in dogs can be surgically corrected. The two most common procedures are TPLO (tibia plateau levelling osteotomy) and the extracapsular tech. Your veterinarian will be able to advise you on the best course of treatment for your dog based on the severity of the injury.

2. Strain or sprain

Very commonly, sudden limping in the back leg of dogs may be due to a sprain or strain. Strains and sprains, while often grouped together, are slightly different. A strain refers to an injury in a muscle or tendon whereas a sprain is an injury to a ligament.

When a dog experiences a strain or sprain, it often results in pain, inflammation, and swelling in the affected area. This discomfort can make it difficult for the dog to put weight on the injured limb, leading to noticeable limping or reluctance to move. The severity of the limping often corresponds with the severity of the injury, with more serious injuries causing more pronounced limping.

Treatment for strains and sprains primarily involves rest and pain management. In the case of a mild strain or sprain, your veterinarian may recommend limiting your dog's activity for a few days to a few weeks, depending on the severity of the injury. Nonsteroidal anti-inflammatory drugs (NSAIDs) may be prescribed to help manage pain and reduce inflammation.

3. IVDD (Intervertebral Disc Disease)

Intervertebral disc disease (IVDD) is a condition that affects the discs in between the vertebrae of the spine. These discs act as cushions and help to protect the spinal cord. When they become damaged or degenerate, they can herniate and put pressure on the spinal cord. This can cause pain, weakness, and paralysis in the affected dog.

There are two main types of IVDD- acute and chronic. Acute IVDD is most often seen in young, healthy dogs and is the result of a disc herniation. Chronic IVDD is more common in older dogs and is the result of degenerative changes in the discs over time.

Treatment for IVDD depends on the severity of the condition. For mild cases of acute IVDD, conservative treatment with strict cage rest and pain medication may be enough. For more severe cases, surgery may be necessary to remove the herniated disc and relieve the pressure on the spinal cord.

4. Fracture/dislocation

A fracture or dislocation of the back leg can also cause sudden limping. This is usually the result of a traumatic injury, such as being hit by a car or falling from a great height. Fractures can be very painful and may require surgery to repair. Dislocations can also be painful and may require manipulation under anesthesia to put the joint back into place.

5. Iliopsoas muscle injury

The iliopsoas muscle is located in the hip region and is responsible for flexing the hip joint. This muscle can be injured by trauma or overuse. When it is injured, it can cause lameness in the affected leg. This type of lameness commonly worsens after exercise and when rising from lying down.

Treatment for an iliopsoas muscle injury typically includes rest, ice, and anti-inflammatory medication. Physical therapy may also be recommended to help strengthen the muscle.

Notable Mention - Osteosarcoma

Bone cancer is another possible cause of a dog limping on the back leg. This type of lameness is usually very pronounced and is not relieved by rest. Common sites for bone cancer (osteosarcoma) to develop in the back legs of dogs include the proximal tibia and distal femur. These locations are close to the knee.

Given the high degree of pain associated with osteosarcoma, there are often other symptoms, in addition, the severe lameness. These can include weight loss, decreased appetite, and fatigue.

Unfortunately, bone cancer is very aggressive and difficult to treat. The most common course of treatment is amputation of the affected limb followed by chemotherapy. However, this is not always successful, and the prognosis for dogs with bone cancer is generally poor.

If your dog is suddenly limping on its back leg, it is important to have them seen by your veterinarian as soon as possible. There are many possible causes of sudden limping in the back leg of dogs, including a ruptured ACL, strain and sprains, IVDD, fracture/dislocation and iliopsoas muscle injury. Bone cancer is another possible cause of sudden limping in a back leg and usually causes a very pronounced and painful lameness. Your veterinarian will be able to perform a physical examination and diagnostic tests to determine the cause of your dog's lameness and recommend the best course of treatment.