Similar to dogs, joint disorders of the cat are common. Despite this fact, the reported treatment options for cats with joint
disease are limited. The object of this presentation is to describe the clinical findings, surgical / arthroscopic findings
and post-operative management of cats with joint disorders including elbow osteoarthritis and medial compartment disease,
shoulder osteoarthritis and medial shoulder instability, and cranial cruciate ligament insufficiency.
As in dogs, the radiographic findings of osteoarthritis do not always correlate well with clinical function. In a radiological
study involving cats of all ages, 22% showed evidence of radiographic osteoarthritis, and when patient records were consulted,
33% of these cats also had clinical signs. Affected cats were significantly older than the control population. These authors
also suggested that there may be little correlation between radiographic and clinical findings or that clinical signs of osteoarthritis
in cats are not easily recognized.
In a recent study at a university referral hospital, the prevalence of radiographic signs of DJD was 33.9%, and the prevalence
of clinical signs was 16.5%, with most affected cats being 10 years of age or older. These authors further classified their
findings into DJD and osteoarthritis, the second being less common. The elbow joint was the most commonly affected joint in
some published studies. However, when osteoarthritis (rather than DJD) was specifically described, the hip joint was most
frequently affected. Many cats have multiple affected joints, and bilateral involvement is common.
Compared with the radiographic features of feline osteoarthritis, the clinical signs of feline osteoarthritis are not well-documented.
Unlike in dogs, lameness is not common in cats with DJD or osteoarthritis. Because of cats' small size and their innate agility,
they can often cope with severe orthopedic disease. In addition, bilateral involvement is common, which makes lameness difficult
to detect. It is also notoriously difficult to elicit pain on clinical examination in some cats.
In one clinical study, 28 cats that had historical or clinical evidence of osteoarthritis, or both, together with radiographic
evidence of osteoarthritis were recruited for a prospective study. Their median age was 11 years. In addition to the cats'
undergoing a clinical examination by a veterinarian, the owners filled out a questionnaire on their cats' general demeanor,
food intake, and lameness. On physical examination, periarticular thickening was a common finding but decreased range of motion
was not. Crepitus was not detected, and synovial effusions were seldom present. Cats were treated with oral meloxicam for
one month and reevaluated. Most owners thought their cats improved, and the most common clinical sign that improved was the
willingness to jump and the height of the jump. Improvement of the stiff gait seen in many cats at the beginning of the study
was also significant.
Clinical experience suggests that the behavioral changes that accompany osteoarthritis may be either insidious and easily
missed or assumed to be inevitable with advancing age, so the owner does not seek veterinary advice. Because of a pet cat's
lifestyle, lameness or exercise intolerance is not a common owner complaint. Changes in behavior such as decreased grooming,
a reluctance to jump up on favorite places, an inability to jump as high as before, and soiling outside the litter box should
prompt the veterinarian to look for sources of chronic pain. Other changes that owners report are altered sleeping habits
(an increase or decrease), withdrawing from human interaction, hiding, and a dislike of being stroked or brushed.
Inactivity, which may result from chronic joint pain, is much more difficult to determine in cats than in dogs since cats
naturally sleep a lot and are often solitary. In many cases, the owners are not home all day to monitor their cats' activity
levels and may not know whether they have changed. Activity monitors attached to cat collars and harnesses have been used
to monitor daily movement in cats, including in cats with osteoarthritis during treatment with oral meloxicam or placebo.
In that study, the activity counts increased with five days of nonsteroidal anti-inflammatory drug (NSAID) treatment, suggesting
alleviation of musculoskeletal discomfort.
It is common for owners and veterinarians not to realize how affected a cat was until they see dramatic improvements after
treatment, emphasizing that analgesic trials may sometimes be the only way to confirm that pain was present.