Healthy Pets

Dog Bone & Joint Health

posted: 05/15/12
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Jumping, running, fetching, digging... all specialties of dogs and puppies because of their nervous and musculoskeletal systems. Learn more about their anatomy, function, and diseases of bones, joints, muscles, ligaments, tendons, and nervous system.

When abnormal stress is placed upon the skeletal system, fractures or breaks of the bones may occur. All the possible fracture types and the proper corrections of fractures are described by difficult terminology. Basically, we refer to fractures not only based on the name of the bone broken but also on the characteristics of the break itself.

Types of fractures

There are four commonly seen fractures in the dog: closed, compound, epiphyseal (growth plate), and greenstick (hairline). These first three types can be further characterized by whether they are simple fractures in which the bone breaks into only 2 or 3 pieces, or comminuted where the bone shatters into many pieces.

Closed Fractures: Closed fractures are those in which the skin is not broken. The bone is fractured, but the overlying skin is intact.

Compound Fractures: Compound fractures are breaks in which the broken bone protrudes through the skin, and is exposed to the outside. Compound fractures are risky in that the bones can be contaminated with dirt and debris, resulting in an infection.

Epiphyseal Fractures: Epiphyseal fractures are commonly seen in young, growing dogs. In animals less than one year of age, there are soft areas near the ends of each long bone where growth takes place. These soft areas are referred to as growth plates or epiphyseal plates. Because these are areas of growth, they are rich in immature non-calcified cells that form a soft, spongy area of the bone. These growth plates are more easily fractured because they are the weakest part of the bone. The distal ends of the femur (thigh bone) and humerus (upper front leg) seem to be particularly susceptible to this fracture.

Greenstick Fractures: Greenstick fractures are small cracks within the bone which leave the bone basically intact, but cracked. In other words, the bone is not completely broken.

What are the symptoms and risks of fractures?

The symptoms and risks depend on what area and to what extent the bone is fractured. Fractures involving a joint are the most serious. A broken back may displace the spinal cord and cause complete paralysis. All fractures, however, are serious and should be treated at once. When a bone within a leg is broken, the dog will usually hold the entire leg off the ground. No weight is placed on the paw. With a sprain or lesser injury, it may use the leg somewhat, but walk with a limp.

What is the management?

Just as in human medicine, splints, casts, pins, steel plates, and screws can be used to realign the bone and allow healing. The treatment depends on the type of fracture, age of the dog, and which bone is broken. Compound fractures in which the risk of infection is high are treated differently than closed fractures. Growing puppies may heal in as little as five weeks, and because of their size they put less weight on the bone. Therefore, a fracture in a young puppy may be treated with a cast but the same fracture may need to be 'pinned' in a geriatric (senior) dog in which healing may take twelve weeks or more. Hairline fractures may only require rest, while surgical intervention will usually be needed in more severe fractures. Careful evaluation by a veterinarian will determine the proper treatment.

A dog's spine is made up of numerous small bones called vertebrae. These extend from the base of the skull all the way to the end of the tail. The vertebrae are interconnected by flexible discs of cartilage - the intervertebral discs. These discs provide cushioning between each bone and permit the neck, spine, and tail to bend, allowing changes in position and posture. Above the discs and running through the bony vertebrae is the spinal cord, which is made up of a mass of nerve fibers that run back and forth between the brain and the rest of the body.

What is diskospondylitis?

Diskospondylitis (also spelled 'discospondylitis') is a bacterial or fungal infection of the vertebrae and the intervertebral discs in dogs. The resulting swelling, inflammation and bone deformities seen in diskospondylitis put pressure or compression on the spinal cord which runs through the vertebrae. The disease is termed "spondylitis" when only the vertebrae are involved. The disease should not be confused with 'spondylosis,' which is a non-infectious fusion or degeneration of the vertebrae.

What causes diskospondylitis?

Diskospondylitis seems to occur most commonly in areas of the country that have a problem with plant awns (e.g., grass seeds, fox tails). It is thought that bacteria or fungi on the awns enter the blood system when the awns pierce the skin. Bacterial endocarditis, urinary tract infections, or dental disease/extractions may be another means by which bacteria enter the bloodstream and infect the vertebrae. Brucella canis has also been found to cause the disease in dogs.

What are the symptoms of diskospondylitis?

Common symptoms of this disease include weight loss, lack of appetite, depression, fever, and back pain. Dogs with this disease are generally reluctant to run or jump.

How is diskospondylitis diagnosed?

Diagnosis of diskospondylitis can be difficult. Blood tests, urinalysis, radiographs (x-rays), and spinal taps may be necessary to diagnose the disease. Cultures of blood and urine are often performed to help isolate the cause and choose the appropriate treatment. Myelography may be indicated to determine the exact location of spinal compression. Surgery may be needed to reduce the compression on the spinal cord.

How is diskospondylitis treated?

Treatment is based on finding the causative agent - fungal or bacterial. Because bone infections are difficult to treat, therapy lasts at least six weeks and may continue for six months or more. Taking radiographs at regular intervals during treatment helps monitor the progress. The lesions seen early in the disease should resolve with treatment.

Clinical improvement (lessening of symptoms) usually occurs within two weeks of starting treatment. Pain medication may be needed early in treatment. Exercise restriction may help decrease the pain also.

The prognosis depends on the ability to eliminate the infection and on how much nerve damage resulted from the spinal compression.

There are a number of reasons a dog may have a head tilt. Dogs with a head tilt may also experience a loss of balance or walk in a circle. In general, head tilt is caused by an abnormality of the vestibular system which includes portions of the inner ear, nerves and brain which help the body maintain balance. The most common cause of head tilt is a middle or inner ear infection, or an infection or inflammation of the brain. Other causes include hypothyroidism, injury to nerves, cancer, toxic side effects of certain antibiotics, and congenital defects. Some older dogs develop a temporary head tilt from an unknown cause. This is sometimes called 'old dog vestibular disease'. Until your veterinarian determines otherwise, head tilt should be considered a sign of a serious disease, and veterinary attention should be sought as soon as possible.

Hypertrophic Osteodystrophy (HOD) is a bone disease that usually affects young, rapidly growing, large breed dogs. The disease has several names including skeletal scurvy, Moeller-Barlow disease, osteodystrophy II, and metaphyseal osteopathy. The disease produces severe lameness and pain and usually affects multiple limbs. The cause of the disease is currently unknown.

Who gets hypertrophic osteodystrophy?

HOD is a disease of young rapidly growing dogs. It usually strikes puppies between the ages of 3 to 6 months. It is primarily a disease of large or giant breeds of dogs although there can be exceptions to this rule. As with most of the young, large breed bone disorders, it affects males more commonly than females. There does not appear to be an increased incidence in any one large or giant breed. There does not appear to be a strong inherited or genetic link.

What are the symptoms of hypertrophic osteopathy?

Dogs that are stricken with HOD often show symptoms of mild to moderate painful swelling of the growth plates in the leg bones. It most commonly affects the ends of the radius, ulna, (long bones from the elbow to the wrist) and tibia (long bone from the knee to the hock). The dogs may show lameness and a reluctance to move. They may be lethargic and refuse to eat. A fever may come and go rising as high as 106 degrees. The disease usually affects both legs at the same time. The symptoms may wax and wane and resolve on their own or if the fever is very high for long periods and the bony involvement severe, the dogs may suffer permanent structural damage or even die.

How is hypertrophic osteodystrophy diagnosed?

Diagnosis is based on the history, symptoms, physical exam showing pain and swelling at the growth plates, and with x-rays. The x-rays will show a thin radiolucent (dark) line at the metaphysis (growth plate) in the end of the ulna, radius, or tibia. Bony inflammation and bone remodeling may also be seen at these sites. Occasionally there may be involvement and changes in the skull and teeth. Dogs often have a fever and occasionally a high white blood cell count.

What is the treatment?

The treatment is generally supportive. Since this is a very painful condition anti-inflammatories and painkillers such as buffered aspirin or carprofen (Rimadyl) are given. (Do NOT give your cat aspirin unless prescribed by your veterinarian.) In addition the animals are usually given a broad-spectrum antibiotic. Strict rest on a comfortable warm bed is recommended. Feeding a nutritious, highly palatable food will help to encourage some dogs to eat. In severe cases steroids may need to be given to control the pain but because of the possibility of this being a bacterial disease their use may be contraindicated due to their immunosuppressive qualities. Vitamin C is often supplemented though its benefit may be questionable.

What causes it and how is it prevented?

The prevention lies in understanding what causes this disease. Unfortunately there is currently no agreement on the cause of this disease. One possible cause may be a bacterial infection. The bony changes and high fever support this possibility. The difficulty in obtaining a bacterial culture from the site and the sometimes-poor response to antibiotic therapy may fuel the argument against this possible cause.

Another suspect in the disease is vitamin C. It has been shown that dogs with this disease show very similar symptoms and bony changes as people with scurvy (vitamin C deficiency). In addition these dogs often have a lowered blood vitamin C level. However dogs synthesize their own vitamin C and don't have a nutritional requirement for this vitamin. In several studies and in practice, feeding affected dogs high doses of vitamin C does not always alter or cure the disease. Some researchers therefore speculate that the low blood level of vitamin C may be a result of the disease, not the cause.

Another possible cause of the disease may be nutritional. It has been suggested that several bone diseases in young puppies are linked to an excess of protein and calories in the diet leading to the development of these problems. The studies haven't been done that confirm this, though many owners of large and giant breed puppies are currently feeding a diet lower in fat and protein to try to encourage moderate steady growth instead of rapid growth. It is possible that this disease may be caused by several factors. At this time however, we do not know the cause or how to prevent it. Hopefully future studies will give us more information on the cause and prevention of this painful and debilitating disease.

Limping or favoring a foot can be caused by a broken toenail, a cut, a foreign object between the toes, dry or cracked pads, or a burn.

The first thing you need to do is identify the source of the problem by examining your dog's paws closely. Be gentle and use caution when touching a sore paw. Even the most mild-mannered dog is likely to nip if it is not used to having its feet handled and you touch the source of its pain. (We always advise dog owners to handle their dog's feet often beginning at an early age in order to build trust for situations just like this.)

Once you have identified the problem, here is what we suggest:

If the dog has a torn nail, it can be very painful. The fractured nail should be removed entirely. Anesthesia may be required. Hemorrhage should be controlled either with styptic powder, bandage, or cautery. Once the nail is removed, healing will begin. Eventually, a new nail will regrow. This may take months, and the nail may be malformed. Depending upon the injury, antibiotics may be given.

If your dog has a small cut, wash the foot with a wound cleanser and apply an antiseptic ointment. Wrap in gauze and cover with a dog boot. If you have problems keeping the foot bandaged or the cut is large, deep, or bleeding a lot, consult your veterinarian.

If a foreign object is lodged between toes or in the pad, carefully remove it with a tweezers. Burrs and dried mud are common culprits. Hair mats can also form and cause discomfort. Clip back mats. Wash and apply an antibiotic cream if necessary.

Dry, cracked pads need a moisturizer. You can use the same lotions you use on your hands, but if you do, only use for a few days in a row. If pads get too soft they will be vulnerable to injury. We like the Protecta-Pad Cream product for dogs because it moisturizes and toughens pads at the same time. Cover with a boot to prevent pet from licking off the lotion or cream.

Handle mild burns as you would a cut. Wash, apply an antibiotic, and cover with gauze and a boot. If the burn is severe, consult your veterinarian.

Examine your dog's feet weekly as part of your health maintenance check. If your dog is going to be walking or running on surfaces that are hard, very cold, hot, or full of stones, twigs, or other loose objects, consider putting boots on your dog to prevent injury. Clip your pet's nails to avoid broken nails and cut back broken nails. Keep foot pads clean by rinsing off dirt and mud, removing burrs, twigs, stones, etc., and trimming back hair.

Include a close look at your dog's feet as part of your weekly pet health check. If a minor problem does not heal, or there is serious pain, redness, fever, loss of appetite, or you are unsure of what to do, contact your veterinarian.

Myasthenia gravis is a neuromuscular disease that can be acquired as an adult or inherited and seen in the puppy. Similar conditions exist in humans. With this condition there is a failure of the nerves' ability to stimulate and control the actions of certain muscles. Nerves communicate with muscles by use of chemicals called neurotransmitters. In myasthenia gravis the chemical neurotransmitter called 'acetylcholine' is unable to exert its function on the intended muscles resulting in inactivity or paralysis of certain muscles.

What are the symptoms?

Most affected dogs develop a generalized muscle weakness and may collapse with muscular tremors. The symptoms in most affected puppies are noted between six and nine weeks of age. If the muscles of the esophagus are affected there may be an inability to move food into the stomach with regurgitation as a result. Megaesophagus (enlargement of the lower portion of the esophagus) is common.

What are the risks?

Many affected dogs are severely affected. Depending on the extent of esophageal involvement there may be a partial or complete inability to eat.

What is the management?

The treatment for myasthenia gravis is variable and the condition is generally not considered curable. If myasthenia gravis is suspected, a thorough physical exam by a veterinarian is recommended. Diagnostic testing with the drug edrophonium chloride (Tensilon), and a blood test to look for antibodies against certain muscle components will aid in achieving the diagnosis. Complete recoveries have not occurred in puppies.

Dogs affected with megaesophagus as a result of myasthenia gravis must be fed liquid diets. The food is usually placed in an elevated position so dogs eat while standing on their hind limbs. This elevated eating stance allows liquid food to travel to the stomach via gravity.

What is panosteitis?

Panosteitis is a bone disease of dogs that is characterized by bone proliferation and remodeling. It is often painful and can last as long as 18 months though more commonly it lasts from 2 to 5 months. It is characterized by lameness that often comes and goes and changes from leg to leg. It is a common problem in several large breeds and the cause is currently unknown. The treatment is symptomatic but the outcome is usually very good.

Who gets panosteitis?

Panosteitis is most common in large breed dogs between 6 and 18 months of age. Occasionally middle-aged German Shepherds will have a bout of panosteitis. It affects dogs worldwide and has been recognized and studied since the 1950's. Male dogs are much more likely to get panosteitis then females. There is a higher incidence in several breeds including German Shepherds, Great Danes, Doberman Pinschers, Golden Retrievers, Labrador Retrievers, Rottweilers and Basset Hounds.

What causes panosteitis?

The cause of panosteitis is currently unknown. There have been many theories as to the cause of this disease. Originally it was suspected that the disease was caused by a bacterial infection. However several investigational studies failed to isolate any bacteria. In addition, the disease responds poorly to antibiotics, further suggesting a cause other than bacterial.

Other studies showed that if bone marrow from affected dogs was injected into the bones of healthy dogs, the healthy dogs would contract the disease. It has therefore been speculated that a virus may cause the disease. The high fever, tonsillitis and altered white blood cell count would also go along with the viral theory. Another interesting twist to the viral theory is that panosteitis was first identified as a problem at the same time that modified live distemper vaccines became widely available on the market. Since wild distemper virus can be isolated from bone tissue some researchers feel that there might be a link between distemper virus vaccine and panosteitis, however more research in this area will need to be done before any serious speculations could be made.

Another theory is that panosteitis might have a genetic link. Because of the greatly increased incidence in certain breeds and families of dogs it is very likely that there is a genetic component involved in this disease.

Lately there have been some claims that nutrition, particularly protein and fat concentrations in the diet, may have an impact on the incidence of the disease. But here again more research needs to be done to substantiate these claims. Most likely this is a multifactorial disease that has several different causes including viral, genetic and possibly nutritional.

What are the symptoms?

Presenting symptoms include a history of acute sudden lameness not associated with any trauma. It is usually a large breed male dog between the ages of 6 to 18 months. There are periods of lameness lasting from 2 to 3 weeks and it may shift from leg to leg. The most commonly affected bones are the radius, ulna, humerus, femur and tibia, though the foot and pelvic bones may also be involved. The dog may show a reluctance to walk or exercise. When the affected bones are squeezed the dog reacts painfully. Occasionally affected dogs will have a fever, tonsillitis, or an elevated white blood cell count.

How is panosteitis diagnosed?

Panosteitis is often diagnosed based on a combination of presenting signs and radiographs (x-rays). The presenting symptoms are listed above. If a dog is suspected of having panosteitis then radiographs are indicated to confirm the diagnosis. Individual radiographs of each affected limb should be taken. Often radiographs of the unaffected limbs are also taken to compare the bone changes. In early forms of the disease a subtle increase in bone density is observed in the center part of the affected bones. During the middle part of the disease the bone becomes more patchy or mottled in appearance and the outer surface of the bone may appear roughened. In the late phase the bone is still slightly mottled but is beginning to return to a more normal appearance.

How is panosteitis treated?

There is no specific treatment for the disease. Since this condition is often very painful, painkillers such as buffered aspirin or carprofen (Rimadyl) are recommended. (Do NOT give your cat aspirin unless prescribed by your veterinarian.) These products are used as needed to help control the pain. Antibiotics are not routinely used unless there are indications of concurrent infections. In severe cases steroids are used but because of the potential long-term side effects of these drugs painkillers are often tried first. This disease is self-limiting and after it runs its course there are very few long term side effects or need for further treatment. As mentioned earlier the disease usually last for two to five months but can last much longer. There are several conditions with similar symptoms so if a dog continues to have symptoms after the normal period of time or is not responding to treatment, she should be reevaluated.

How is panosteitis prevented?

There is currently no way to prevent the disease. However because of the potential genetic link, breeding animals should be screened to insure that they are not potential carriers of the disease. Despite the numerous puppy foods catering to large breed dogs there is no current evidence that confirms that these foods will lower the incidence of the disease when compared to standard commercial puppy food. If an animal shows symptoms of the disease they should be promptly diagnosed and treated and exercise and activity should be reduced until the symptoms have gone away.

The term swimmer is used to describe a puppy that paddles its legs much like a turtle but is unable to stand. A puppy should be standing and walking by three weeks of age. As a result of weak muscles in the rear limbs, swimmers are generally unable to stand at the normal age.

What are the symptoms?

The only symptom of a swimmer puppy is its inability to stand or walk by the normal age of three weeks. The puppy will instead lay on its chest and paddle its feet as if attempting to swim in a turtle-like fashion.

What are the risks?

Most swimmer puppies will recover with time. The condition may, however, have an inherited characteristic.

What is the management?

Slippery floors may worsen or in some cases may even cause swimmer puppies. This is not always the case because swimmer puppies are also seen when a rough surface is used for raising puppies. In any event, an affected puppy should be placed on a rough rather than slippery surface.

Puppies should not become overweight as this may further the weakness in the rear limbs. Most swimmer puppies will develop to normal functioning by eight weeks of age if treated early and placed on flooring with good traction.

Since there may be a hereditary component to this condition, dogs who were swimmer puppies would not be optimal breeding animals.

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