Heidi writes, “Our cat, Meowser, has some hard object just below her knee joint. We tried to clip the hair around it to see if we could loosen it. It does not seem to be attached to the main part of her leg, but it may be underneath the skin. Although we had her front legs restrained in order to examine the area, she did not seem to be in pain, but remained calm. We also noticed a small hole next to this. It is not red or inflamed. Could this be a Cuterebra?”
Heidi, this object could be just about anything, but it’s unlikely to be a Cuterebra larva if it’s hard. In fact, one of the important considerations in Cuterebra removal is to ensure the larva is not punctured. They are somewhat fragile, and rupture of the organism can result in anaphylactic shock, a potentially fatal reaction.
My first thought was to ask whether your kitty has had surgery in the past, especially orthopaedic surgery of that leg. A truly “hard” object has a density of bone or greater, such as a stainless steel or titanium appliance. Examples would include pins, plates and screws. A bony reaction from a previous surgery would not be unusual. That, too, would be “hard.”
Beyond that, the possibilities are endless, and a trip to your pet’s doctor is unavoidable, as some of those possibilities could be serious.
Chief among those possibilities is the chance that an orthopaedic appliance has entered the joint space of your cat’s knee. A severe, even debilitating arthritis could develop.
Bone cancer is another item on the differential diagnosis list that carries a high degree of potential seriousness.
Another possibility is that there could be a foreign body that entered through the hole you found, and it may need surgical removal.
Once we see a photo of the lesion we will be able to tell you more.
See you tomorrow, Dr. Randolph.