Lameness exam: what am I missing? (Proceedings)
The ability to diagnose the cause of a lameness is essential to the small animal clinician. In our day to day practice settings, dogs and cats present with a variety of lamenesses. Many of these problems resolve with rest, or a diagnosis is readily available (cut pad, ingrown nail, etc…). However, there is a small group of cases in which an obvious cause of the lameness is not available to the clinician. It is this group of animals which will be examined in this discussion and these dogs and cats, although small in number, can soon become a major drain on your time and patience. As with any case, an accurate history, signalment and a complete physical examination are the cornerstones to our data base.
Once a lameness persists in a patient and your initial management fails to resolve the problem you are faced with a different situation. To effectively work up this type of case, there are some important things to remember. First and foremost, allow adequate time to assess the animal. This is true even if you have seen the dog or cat a number of times previously. This is not the case to schedule a 10 minute appointment in-between surgeries.
History and Signalment:A lameness may be sudden or acute in development or slow and insidious in onset. Be sure to obtain the following information from the client: (1) The owner's complaint, (2) How and when did the problem develop (3) Overall duration of the problem (4) Does the lameness vary in severity (5) Previous treatments and associated response (6) Additional information such as diet, environment, previous injury, etc…
A complete physical examination should be conducted. Remember, the problem is a lame animal, not just a lame leg. Many persistent lamenesses are manifestations of diseases that affect other systems of the body. The exam has two major aspects, observation and palpation of the patient. Observation should start in the exam room but is not limited to this confined space. Examine the conformation, use of limbs, swellings, etc. Also, evaluate the animal's attitude. At this time you can get an overall impression of the animal's general body condition. Following a brief TPR and basic exam (temp, chest auscultation, and general examination of the eyes, ears, nose and mouth), observation of gait should be done.
Evaluate multiple gaits including a walk and trot. Lameness in dogs and cats is manifested in various ways. If one or more limbs do not perform to their average capacity in supporting the animal, the sound limbs must accept increased responsibility of weight-bearing. This results in a shifting of the center of gravity toward the more sound limbs. Oscillations of the center of gravity are then greater than normal producing a visible imbalance "what you visualize as the lameness." Dogs will show the same gait abnormalities as horses. One example is with a forelimb lameness, where the dog will lower the head when the sound limb is on the ground and will throw the head up when the lame limb is in the stance phase. Also unilateral rear limb lameness may be associated with a "hip hike" of the affected limb and extension of the head during the stance phase the affected limb. Dogs will also place a lame limb forward during standing and will point "toe out" the paw of the affected limb. Often less weight is supported through the lame limb which can be picked up more easily than the contralateral sound limb.
At this point, a brief neurological exam is performed. While a more complete exam may be necessary later, at this time one should assess cranial nerves, neck movement and proprioceptive responses in all limbs. Also check myotactic reflexes.