Major force is necessary to rupture a joint and displace the bones. Such injuries usually are the result of falls, fights with other animals, or car accidents. The cat may also be in shock and have internal bleeding from injured organs. Signs of dislocation are sudden pain with the inability to bear weight on the limb. There is an observable shortening of the limb when compared with the opposite side.
The hip is the most commonly dislocated joint in the cat. It can be recognized by signs of pain on movement of the hip, a gritty sensation, and shortening of the leg by about 1 inch (25 mm). Other joints less frequently dislocated are the patella (kneecap), hock, and jaw. A dislocated kneecap occurs with some frequency in the Devon Rex; the breed has a hereditary predisposition. It is also seen in Maine Coon Cats.
Cats can get a variety of intestinal parasites, including some that are commonly referred to as “worms.” Infestations of intestinal worms can cause a variety of symptoms. Sometimes cats demonstrate few to no outward signs of infection, and the infestation can go undetected despite being a potentially serious health problem. Some feline parasitic worms are hazards for humane health as well.
In this cat with a dislocated hip joint, the affected right leg is shorter than the left one.
Treatment: Veterinary examination is necessary to rule out an associated fracture and to replace the joint in its socket. Treating other injuries may take precedence, because a dislocated joint is not life threatening. Replacing a joint in its socket often requires sedation or anesthesia, and the cat may need to wear a splint or wrap to hold the joint in place for a short time while the damaged tissues heal. If a joint has been dislocated for a long time, surgery may be required to replace it or, in extreme cases, the involved joint may need to be removed; for example, in some hip dislocations the femoral head is removed.
WebMD Veterinary Reference from "Cat Owner's Home Veterinary Handbook"