Osteochondrosis (OC) in Dogs

Overview of Canine Osteochondrosis

Osteochondrosis (OC) is an important developmental orthopedic disease in young, large-breed dogs. It is considered to be a clinical problem of the same magnitude as hip dysplasia.

Cartilage is the tissue, normally at the ends of long bones, which contributes to pain-free motion. OC is a congenital defect in normal joint cartilage development that results in either a loose piece or flap of cartilage. This loose piece or flap of cartilage causes secondary joint osteoarthritis.

Secondary arthritis or degenerative joint disease (DJD) is very different from the primary arthritis that occurs in humans. The dog’s body recognizes the cartilage flap as abnormal and this induces the secondary arthritis. These problems generally occur early in the dog’s life, as opposed to the “wear and tear” arthritis that people manifest later in life.

The joints involved with OC in dogs (from most common to least common) are:

• Elbow
• Shoulder
• Stifle (knee)
• Hock (rear leg, beneath the stifle)

The amount of secondary DJD present when the OC condition is diagnosed is “there to stay”; however, most surgeons feel that if the condition is dealt with in a timely manner, further development of DJD could be lessened.

Diagnosis of Osteochondrosis in Dogs

Diagnostic tests are needed to recognize OC and exclude other diseases that may cause lameness in young dogs. Many times, the veterinarian will suspect OC based on signalment (age, sex and breed), history and clinical examination. In addition to obtaining a medical history and performing a thorough general physical examination, other tests that your veterinarian may wish to perform include:

• A thorough orthopedic examination. This usually shows lameness and joint pain or swelling.
• Radiographs (X-rays) of the affected joint. These can illustrate the primary OC problem or show the secondary DJD that results from it.
• Joint contrast studies (arthrogram). Occasionally injecting dye into the joint and taking a radiograph may be helpful in establishing a definitive diagnosis of OC.
• Blood tests. These can be done to determine your pet’s general health, particularly if surgery is being considered. They are also done to assess the risks to your pet in undergoing anesthesia.
• Magnetic resonance imaging (MRI) or computed tomography (CT).
  These are specialized tests that are sometimes performed at large referral centers.

Treatment of Osteochondrosis in Dogs

Treatment for OC may include the following:

• Surgical treatment is usually recommended for dogs suffering from OC, but the exact type of surgery performed depends on the joint involved.
• The goal of the surgical procedure is to remove any loose pieces of cartilage from the joint surface and curette (scrape) the cartilage defect to stimulate filling of the defect.
• In the elbow joint, fragmented coronoid process (FCP) and ununited anconeal process (UAP) are reported to be manifestations of OC. Fragmented coronoid process is a very frequent cause of foreleg lameness and surgical removal of the loose process is recommended.
• At some centers, arthroscopic surgery is used to treat lameness associated with OC.
• Chondroprotective nutraceutical agents such as chondroitin sulfate and glucosamine (Cosequin®) are probably beneficial, especially during the time of cartilage healing.

Home Care and Prevention

After your pet has joint surgery, you will need to limit exercise for three to four weeks after surgery. Follow your veterinarian’s instructions regarding physical therapy and medications.

Since many of these animals have experienced rapid growth, some veterinarians feel that feeding lower protein diets without supplements may be helpful in decreasing the incidence of the disease. Discuss this issue with your veterinarian.

In-depth Information Canine Osteochondrosis

Osteochondrosis (OC) is being increasingly recognized as a leading cause of lameness in many large-breed dogs such as the Rottweiler, Labrador retriever, Bernese mountain dog and Newfoundland. OC is a developmental disease which means affected pets are born with a defect in normal joint (cartilage) development. This defect typically causes lameness at an early age.

This abnormal development results in various clinical syndromes. All of the elbow diseases that occur in young dogs secondary to OC can be lumped together under the term “elbow dysplasia.”

• Fragmented coronoid process (FCP) of the elbow joint. Currently the most important of the diseases that fit under the umbrella of OC, FCP results from either an abnormal cartilage development of the coronoid process of the ulna or an abnormal development in the length of the radius and ulna bones between the elbow and wrist. A small piece of the coronoid process fragments (hence the name fragmented coronoid process) inside the elbow joint sometime between 4 to 6 months of age. This very small fragment elicits a secondary arthritis at an early age (five to ten months).
• Osteochondritis dissecans (OCD). This joint condition is related to OC. OCD can occur in the shoulder, stifle (knee), hock (joint below the knee) and elbow. OCD of the shoulder was once the most commonly recognized form of OC; however, FCP is now more commonly diagnosed. OCD of the shoulder occurs when there is abnormal ossification or development of the joint cartilage of the upper portion of the humerus. A layer of thicker cartilage results from the osteochondrosis. This thicker cartilage can crack, cause a fissure and dissect (hence the name dissecans) a cartilage flap. This causes secondary joint inflammation and lameness. Like FCP, OCD affects young, large-breed dogs. This condition also frequently affects both front legs.
• Ununited anconeal process (UAP) is generally thought to fit under the umbrella of OC. In dogs with this disease the anconeal process of the ulna separates from the host bone and causes a large, free piece of cartilage and bone in the elbow joint. This causes severe secondary degenerative arthritis. Although originally reported in young German shepherd dogs, this disease has been reported in most large breeds. UAP has also been reported in large chondrodystrophied (dwarf-like with short, curved legs) breeds, like the basset hound.

Veterinary care should include diagnostic tests and subsequent treatment recommendations.

In-depth Information on Diagnosis

Diagnostic tests are needed to recognize OC and exclude other diseases causing lameness in young dogs. The age, breed and clinical signs are characteristic for the disease and may cause your veterinarian to strongly suspect these conditions. OC should be suspected in any large-breed dog less than two years of age that is lame. Tests that your veterinarian may wish to perform include:

• Orthopedic examination. In addition to lameness, affected dogs may exhibit pain on extreme flexion or extension of the joint. An effusion (increased amount of joint fluid) may be present in the affected joints.
• Radiographs of the affected limb. After a careful lameness exam, radiographs (X-rays) of the joint are probably warranted to help identify the cartilage defect or the subsequent osteoarthritis.
• Arthroscopy. As arthroscopy is becoming more advanced in small-animal orthopedics, the procedure may be recommended to help confirm the diagnosis.

In-depth Information on Treatment

Treatment for OC in dogs may include the following:

• Most surgeons recommend early surgical treatment when OC or one of its clinical syndromes is diagnosed. If the offending piece of cartilage is removed at an early age, the secondary arthritis that develops will probably be less severe.
• When FCP is suspected, a small surgical incision is made into the joint to expose the loose piece of cartilage and bone and allow the abnormal cartilage to be débrided or removed to hasten its healing. If the amount of arthritis is severe, some surgeons recommend cutting the ulna to allow a newer portion of the joint to bear additional weight. The addition of the osteotomy (bone cut) has yet to be proven to have a substantial clinical benefit. This procedure can be performed on both forelegs using conventional or arthroscopic surgery.
• With OCD of the shoulder, elbow, stifle (knee) or hock (joint below the knee) joints, surgical exploration is also recommended. A characteristic large cartilage flap is present and should be removed to decrease the degree of secondary arthritis. Following either conventional or arthroscopic cartilage flap removal, the cartilage bed is débrided to stimulate healing.
• With UAP, a large piece of the anconeal process is not fused properly. The standard treatment has been to remove the process surgically; however, because of continued joint instability, secondary degenerative arthritis occurs. There have been recent reports of attempting to re-attach the process with a screw or allowing the body to fuse the process back on the ulna by “taking pressure” off of the bone by an ulnar osteotomy. Although some patients have had successful results with these procedures, the overall results are not yet known.
• Chondroprotective agents like glucosamine and chondroitin sulfate probably play a beneficial role in the healing of cartilage, and patients should be supplemented with these nutraceuticals. However, how long these should be given is not known.
• Non-steroidal anti-inflammatory medications (NSAIDS) are helpful to ameliorate the clinical signs of secondary arthritis and may play a role in long-term management of these patients.

Follow-up Care for Dogs with Osteochondrosis

Your veterinarian will usually prescribe pain medication to ensure your dog’s comfort, prior to definitive diagnosis and/or in the aftercare period from surgery. This can be done through the use of pills or narcotic pain patches (placed on the skin) that release a constant level of pain medication.

Prior to definitive therapy, you should limit your pet’s activity to reduce pain and minimize the chance of a pathologic fracture occurring. Your pet should not run, jump or play during this time and should be watched carefully. Give assistence when he climbs stairs or gets in and out of the car.