Limping and Lameness

One of the most common reasons that animals are presented to veterinary clinics is for evaluation of limping. Limping can be a sign of numerous conditions ranging from mild sprains and strains to severe fractures or even cancers. The remainder of this article will cover ten of the most common reasons for limping, how limping and lameness is diagnosed, and some of the treatments available for these conditions.

Common Injuries

Sprain, Strain, Overuse, and Fatigue. The most common cause of acute onset lameness is due to sprain, strain, overuse, or fatigue. Animals will often present with mild to moderate lameness after a period of exertion, rough play, or accidental trauma and will typically recover quickly.

Foreign Bodies and Caustic Lesions. Foreign bodies such as thorns, sticks, and seeds can cause lameness in pets. While most people tend to assume that lameness is due to "something in the paw" the majority of patients seen for limping typically have some other problem. Contact with substances that cause blistering or burns on the pads or between the toes can cause tremendous pain and lameness as well. 

Panosteitis. Panosteitis is an inflammatory condition of the long bones that occurs most commonly in young, growing animals. Larger breed dogs tend to be affected more commonly. Lameness can occur in one or more limbs and may get better and worse over a period of time. While the exact cause of panosteitis is not known, it is important to realize that this disease is self-limiting, meaning it will resolve with time.

Osteochondrosis dissecans (OCD). OCD is a condition in which a small flap of cartilage becomes dislodged within a joint space. The small flap can cause pain and discomfort and secondary arthritis. It is most common in over-fed, rapidly growing puppies. OCD most often occurs in the forelimbs but can occur in the hind limbs as well.

Infection. Superficial bacterial and fungal infections of the skin and nail beds can cause various degrees of lameness. Additionally, bacterial infections, like Lyme disease, or fungal infections of the bone can occur. These, deeper infections are harder to treat and are more severe.

Arthritis. Arthritis is one of the most common conditions of chronic lameness in older dogs and cats. It can be the result of old trauma or injuries, related to genetics (some breeds are more prone), or just a part of the aging process. 

Back and Neurologic Issues. Many neurologic conditions can often present as lameness. Intervertebral disk disease occurs when a portion of the intervertebral disk ruptures out of place. The resulting swelling can cause pain, lameness, or even paralysis.

Cranial Cruciate Ligament (CCL) Tear. Partial or complete tears of the CCL can cause mild lameness to complete non-use of the rear limb. Trauma is the most common cause of CCL tear.

Fractures. Fractures of the limbs and vertebral column can cause profound lameness and swelling. Most fractures are associated with trauma although some pets may experience spontaneous fractures due to a variety of other conditions. 

Tumors and Cancers. Tumors or cancers of the bone, cartilage, or muscle can result in lameness of any limb with or without swelling. Early on, the animal may have mild signs of discomfort that respond to pain medications. Over time, however, the lameness will typically get worse.

Diagnosis

The methods used to diagnose lameness will vary based on the severity and duration of the injury. In all cases, a careful physical examination should be conducted to identify the location or source of discomfort, if swelling and bruising are present, and if there are other concurrent problems such as evidence of neurologic dysfunction. In many instances radiographs (x-rays) may be taken to rule out the possibility of fractures or other boney lesions such as degenerative joint disease (arthritis), poor anatomical alignment, or changes in bone density. 

Advanced diagnostics such as nuclear scintigraphy, CT/MRI, and arthroscopy may be considered in some cases. These technologies allow for the visualization of structures and abnormalities that regular x-rays will not be able to identify. Nuclear scintigraphy uses radioactive dye to look for areas of metabolic activity in bone. It can be good to identify hairline or stress fractures that are too small to be seen on an x-ray or for the early identification of potential tumors. CT and MRI can allow for the examination of supporting structures, such as ligaments and tendons, and intervertebral disks. These structures do not show up on regular x-rays and can therefore be difficult to evaluate without more invasive techniques. Arthroscopy can be used for the diagnosis and treatment of some conditions. With arthroscopy, a small camera (arthroscope) is introduced into a joint space to directly examine the boney and non-boney structures within the joint. If a cartilage flap (OCD) or small boney chip is evident, it can be removed with the scope.

Other diagnostic tests may be considered in certain instances. For example, a bone biopsy may be indicated to confirm bone and cartilage cancers or bone infections. Specialized blood tests may be indicated to diagnose tick-borne or fungal illnesses that can cause lameness. 

Treatment

Treatment will vary by the condition. For minor conditions such as sprain, strain, overuse, and fatigue, medical management including rest and pain medication may be all that is necessary to allow the animal to recover fully. Currently, there are 5 pain medications in the non-steroidal (NSAID) class that are approved for veterinary use. They are Rimadyl, Etogesic, Deramaxx, Metacam, and Zubrin. The choice of medication will vary depending on several factors. The use of human pain medications such as aspirin, Tylenol, Advil, etc. should be discussed with a veterinarian before administration to pets as some of these medications can have serious side effects. 

For chronic or longer-term conditions, such as arthritis, intervertebral disk disease, panosteitis, and bone infection other medications such as steroids, antibiotics, Cosequin, and Adequan, may be used. The specific condition and status of the pet will dictate what combination of medications will be most appropriate.

For more severe conditions, surgical treatment may be the only option. Typically, fractures will require some sort of stabilization procedure to allow the bones to heal properly. This can involve splinting or casting for well-aligned, simple fractures, or internal fixation procedures such as IM pins, wires, or plates, for more complicated or misaligned fractures. For cruciate ligament tears, placement of nylon line or other methods of stabilization will be necessary for a return to normal use and limitation of secondary arthritis. For boney or cartilage tumors, amputation of the affected limb, chemotherapy, and/or radiation therapy may be necessary to preserve a high quality of life for the patient. 

Given the wide variety of conditions that can cause lameness and the vast number of diagnostic and treatment options that are available, seeking veterinary attention early in the course of lameness is often the best option for complete recovery. 

The information provided is for educational purposes only and is not intended to take the place of your regular veterinarian. Please do not hesitate to contact your regular veterinarian if you have questions regarding your pet.