In-depth Information on Lameness in Dogs
Sudden causes of lameness are generally more easy to define. If your dog was completely normal before taking exercise and suddenly comes up lame, obviously something happened that created a gait abnormality. Trauma of some type is most likely, although this can be extremely variable.
In all of these examples, the pet has gone from normal to abnormal within a short period of time, but this does not necessarily mean that defining the lameness is always easy. In some cases it is possible to hone in on the correct area, for example the knee, and from there, try to define the problem more accurately.
Sometimes dogs will develop sudden onset lameness when the underlying problem has actually been around for some time. A dog with a low grade, partially torn cruciate ligament may suddenly progress to a full blown tear, but there can be chronic arthritis and soft tissue thickening of the joint suggestive of a more long standing problem. Some pets with bone tumors of the limbs can suddenly develop a severe lameness associated with a fracture of a bone at the site of the tumor. These fractures are often associated with more minor trauma, such as slipping on a kitchen floor, an incident that would not normally be thought of as causing a broken bone.
Sudden onset lameness may be the initial presentation associated with a variety of spinal disorders. Extruded disk material in the neck region can causes a profound, single front leg lameness, a so-called root signature, as can disk problems in the lumbo-sacral region of the spine. Disk disease and fibrocartilaginous emboli (FCE) can produce rapid onset weakness and clumsiness that can be misinterpreted as lameness.
Many lameness problems are noted in young and growing animals. These problems often improve with rest and get worse during exercise, such as elbow dysplasia. They start out as low grade and become progressively more severe over a period of a few weeks.
Overt lameness of one or more legs may not be what an owner initially notices. It may be a reluctance to go up or down stairs, not eager to exercise, or just not acting as lively and bouncy as one might expect for a puppy. This often occurs in hip dysplasia in dogs, causing gait abnormality rather than causing specific limb lameness.
Some owners may pick up on subtle gait abnormalities, such as swinging a limb rather than flexing specific joints. Agility, endurance and working dogs may present with more mild and challenging sports injuries that affect performance but produce only minor problems in one or more limb.
Sometimes lameness due to an orthopedic disorder can be misinterpreted as a neurological disease. Dogs with cruciate injuries to both stifles can find it extremely difficult to walk and when they do can appear to be weak and clumsy on their back legs, similar to dogs with disk disease.
Careful history taking can be crucial in the diagnosis of many types of lameness. After noting your pets age, sex and breed and asking about general health issues, questions specific to the lameness may include:
a) How long has the problem been going on?
b) Is it getting better or worse?
c) Is it worse in the morning, worse at night, worse after rest, worse after exercise?
d) Does it wax and wane or remain constant?
e) Does your dog cry in pain?
f) Has it responded to any treatment?
Following a general physical examination your pet will be observed as he/she sits/stands in the examination room. For dogs it is common to observe walking and trotting. Sometimes owners find it helpful to bring along home videos of their pet’s gait, particularly if the problem appears to come and go.
Orthopedic evaluation usually concentrates on examination of all four limbs, palpating the bones, muscles and joints for pain, swellings and decreased or abnormal ranges of motion. Your veterinarian may also focus on specific areas to look for certain causes of lameness in areas like the hip (hip dyplasia – Ortolani maneuver), elbow (elbow dysplasia) and stifle (cruciate disease – cranial drawer sign).
Your veterinarian will also manipulate the neck and palpate the spine along its length. If neurological disease is suspected a more detailed neurological examination will be necessary.
If an abnormality of bone or joint is detected on the examination, radiographs of that region may be taken. Radiographs are not always necessary, however, although they can be helpful to confirm a suspected diagnosis, to discover the exact diagnosis (say there is elbow pain but the exact cause could be one of several different problems with different treatment plans) or to give an owner a more accurate prognosis.
Sometimes, with more subtle problems, it is necessary to radiograph the opposite normal limb for the purposes of comparison. Radiographs may lead to a suspicion of a certain problem, but not definitive confirmation. In some cases, further x-rays of the same site, taken in another 4 to 6 weeks may be suggested, to see if the area of interest has changed or the lesion progressed after that time.
Radiographs may also suggest that other diagnostic tests are appropriate such as a biopsy or a joint tap. A joint tap involves the insertion of a sterile needle into a joint, with your pet either sedated or anesthetized. The fluid is evaluated to define the type of pathology present in the joint.
In certain challenging lameness cases, CT scans or MRI can be helpful, such as in the diagnosis of a subtle cruciate injury in the knee. Alternatively, arthroscopy, that is visualization of the inside of the joint using a small camera inserted into the joint, can be minimally invasive and allow diagnosis of certain joint diseases. This is a less invasive alternative to surgically opening the joint, and obviously there is less discomfort associated with arthroscopy.
Where neurological disease is suspected, specific diagnostic tests may include myelography, CT scan, MRI, and spinal taps.
On occasion, injection of a water-soluble dye into a joint, a procedure called arthrography, can be helpful to define the extent and shape of a joint. Problems of the biceps tendon that runs through a sheath in the shoulder joint can be demonstrated, in some cases, using this technique.
Use of bone scans has limited applications in the diagnosis of small animal lameness.
Most lameness problems do not produce a specific change that can be detected with routine blood work. However blood samples may be obtained where infectious or auto-immune causes are suspected, and in cases where an animal will undergo general anesthesia for surgical correction of the lameness.