In dogs, limping is the most common complaint for musculoskeletal disease, and it is easy to ascertain that an orthopedic examination is needed. In cats, the most common presenting complaints for musculoskeletal disease are changes in attitude (eg, being fractious or less playful), poor grooming, urination or defecation outside of the litter box, or the pet owner’s sense of undiagnosed illness in the cat; musculoskeletal disease may also affect mobility and flexibility, contributing to these signs.2,5-7 Inability to induce cats to consistently walk as desired and difficulty differentiating pain from fear or anxiety-related behaviors can also be challenging. Despite these challenges, orthopedic examination is important for diagnosis and establishment of a treatment plan.
Some cats may require sedation or behavior-modifying drugs prior to presentation; anesthesia may be required for staff safety in extreme cases. Although commonly used medications (eg, gabapentin) might not impact examination except in subtle cases, significant sedation or anesthesia may be required if the patient has signs of pain (eg, arousal, increased heart and/or respiratory rate, elevated blood pressure, focal muscle tremors). Examination may also need to rely more heavily on observation of swelling and palpation of abnormalities.
Initially, it is important to observe posture, stance, and ambulation.2 Most cats are not trained to walk on a leash, so the patient may need to be coaxed to walk. Observation of other behaviors may also help localize the problem. For example, cats with hip or back pain may be less willing to jump up on a chair or may attempt to jump and miss, or cats may stand on their pelvic limbs but keep their hips flexed and fully extend their hocks.
During examination, musculature should be palpated for symmetry.2 Muscle atrophy, masses, and/or swelling can provide direction to a specific limb (especially if observation of ambulation was not successful).
Cats that tolerate examination can have unaffected limbs examined first, allowing observation of normal reactivity; this can help in detection of subtle reactions attributable to pain.7 However, most cats only tolerate examination for a short period of time, so beginning with the unaffected limbs may not be prudent in all cases.
It is important to start at the distal aspect of the limbs and work proximally. Constant contact should be used, starting from the torso to the digits, as this can be less aversive than just reaching for the digits. Cats are less stressed and may be more cooperative when in a comfortable location or position (eg, reclining, standing, being held by the owner). Cats that fold the limbs under the body can have the chest or pelvis supported while the thoracic or pelvic limbs, respectively, are examined (Figure 1).
When examining a joint, spreading pressure over a wide area with multiple fingers or a palm can decrease the effect of pressure on bones and soft tissues, isolating the joint as the potential source of pain. Otherwise, very focal pressure may cause pain at the gripping point, which can confound assessment of joint pain. Normal range of motion and locations for palpating swelling are presented in the Table.