In this disease a small portion of the ulna breaks off into the joint. This portion of the bone is called the medial coronoid process.
Shifting forelimb lameness is a common clinical sign of the condition
Arthroscopic surgery is very useful to diagnose and treat a fragmented coronoid process.
About 75% of the dogs are helped with arthroscopic surgery, however, arthritis will progress and may require medicines.
What is it?
The elbow joint is made up of three bones: the humerus (upper arm bone), radius and ulna (forearm bones). In this disease a small portion of the ulna breaks off into the joint. This portion of the bone is called the medial coronoid process.
The exact cause for how the coronoid process breaks off is unknown, but one theory is that the radius and ulna bones grow at different rates so that the ulna is longer than the radius which increases the forces bearing on the medial coronoid process, ultimately causing it to break off.
Clinical signs
Although FCP can occur in any breed of dog, it occurs more commonly in large breed dogs such as Labrador retrievers, rottweilers, Bernese mountain dogs, Newfoundlands, golden retrievers, German shepherds and chow chows. Signs that there is a problem usually develop around 5 to 7 months of age, but sometimes do not show up until the dog is fully mature. Owners often note that dogs are stiff after periods of sleep or rest and that the lameness worsens after exercise. Sometimes the lameness is very subtle and it can be difficult for owners to tell which leg is lame.
During a physical examination, a veterinarian may recognize a decreased range of motion (inability to fully flex or extend the joint) in one or both elbows. Crepitation (crackling) of the joint may also be present. Sometimes joint effusion (fluid in the joint) and swelling are evident on palpation and the joint is often painful during these manipulations, especially when pressure is applied to the medial coronoid process.
Diagnosis
One of the first things your veterinarian may recommend is radiographs (x-rays) of both elbows—even if only one elbow seems to be affected—because this disease is often bilateral. This may involve several different views of each elbow joint. Sometimes the fragment cannot be appreciated on radiographs, which does notrule out FCP, and the diagnosis may be made based on secondary signs of degenerative joint disease (DJD). Sometimes patients need to be sedated in order for your veterinarian to obtain good quality radiographs.
Your veterinarian may also recommend a CT (computed tomography) scan of your dogs elbows to better characterize subtle lesions. Sometimes analyzing a sample of the joint fluid (arthrocentesis) can help support a diagnosis of FCP, and is obtained by placing a needle into the joint and drawing back fluid.
Often times routine blood work (CBC, serum chemistry) and a urinalysis is also recommended to help rule out any other underlying diseases or abnormalities. This also serves as a general pre-surgical health screen if surgery is opted for.
Another diagnostic modality is arthroscopic examination of the joint. If the surgeon confirms that a loose bony fragment is present, it is removed.
Treatment
Treatment for FCP may involve medical (conservative) management, surgical or arthroscopic intervention, or most commonly, a combination.
Surgery or arthroscopy is generally indicated for your pet if he or she is lame or painful, and surgery and arthroscopy can stop or slow the progression of DJD. Surgery and arthroscopy tend to be more successful in younger patients (less than 12 months) and in patients that have not yet developed significant arthritis.
Arthroscopy allows the veterinary surgeon to visualize the joint (photo right), remove the fragmented piece of bone and help smooth out any lesions in the joint. Surgery usually involves exposing the medial coronoid process via one of several methods and removal of the fragment.
In the video (right), a fragmented coronoid process is palpated with an instrument. In this case, the fragment moved into the front compartment of the joint and a pair of forceps was used to retrieve the fragment.
Home Care
Following either procedure, it will be important for you to limit your dog’s activity for the first 6-8 weeks. Most dogs are able to walk within the first day or so, but they should be limited to very short leash walks to urinate or defecate. Rehabilitation therapy may include cold packing the elbow(s) for the first few days and warm packing for the next several days to weeks. Flexing and extending the joint after warm packing will help minimize stiffness of the elbows. After that, a gradual increase in activity will generally be allowed.
Whether or not your pet has surgery, he or she may need long term medical therapy to help with elbow arthritis. This often involves short term pain medication after surgery, such as Tramadol. Tramadol can cause signs associated with stomach upset, and should be discontinued if constipation, vomiting or loss of appetite occur. Dogs are often also put on a non-steroidal anti-inflammatory drug (or NSAID), which will help with both pain and inflammation. A common NSAID used in veterinary medicine is Rimadyl. It, too, can cause stomach upset and if your dog experiences vomiting, diarrhea, black stools or loss of appetite, it should be discontinued and your veterinarian should be contacted. Another medication that is frequently beneficial is gabapentin with reduces wind-up pain.
Some dogs also benefit from a special diet that helps to promote joint health. One such diet is Hills’ j/d diet, which contains omega fatty acids, glucosamine and chondroitin sulfate, all of which may help with joint pain.
Prognosis
About 75% of the patients that have surgery are significantly improved. Some return to normal function, however most have some degree of damage to the joint which may result in stiffness that may be noted when the dog first gets up from rest. Anecdotally we feel that dogs under 9 months of age tend to have a better prognosis, providing that the elbow joint has a good "fit".
Generally improvement in the use of the limb is seen over the first four months. After four months the recovery plateaus and no additional improvement is seen.
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