What is the anatomy of the skeletal system?
The skeletal system is made up of bones, ligaments and cartilage which provides a framework, protects internal organs and gives a full range of motion. The muscles use this framework to do their job of forward propulsion. The hinges of the skeleton are the joints. They give flexibility to walk, trot, run, jump, climb, and move the head and neck.
There are three types of joints. The hinged joints are the knees and elbows. The ball and socket joints are the hip and shoulder joints. The gliding or plane joints are the wrists and ankles. Synovial fluid lubricates the joints for smooth action. The tendons and ligaments give stability. Joint inflammation or arthritis occurs when the joint is damaged by injury or disease. Depending on the source of irritation there are two types of arthritis: degenerative and inflammatory.
What is arthritis and the different types?
When cartilage, which protects the bone and makes up the joint, is destroyed, it is called degenerative joint disease or osteoarthritis. This is a progressive disease that affects the weight-bearing joints such as hips, spine, knees and elbows. About 25-30% of pets suffer with the same pain and debilitation as people. Normal stress on abnormal joints or abnormal stress on normal joint can result in cartilage destruction and changes in the bone. Normal stress on abnormal joint can result in hip dysplasia. Abnormal stress on normal joints can be from constant jumping of obstacles, stretching or tearing ligaments during strenuous exercise or an injury from a fall or accident. Deterioration occurs in the cartilage that protects the bone ends and they become rough instead of smooth as they should be. Cracks develop in the soft spots with progression of the disease. The exposed bone remodels and gets spurs while the cartilage frays. The exposed bone has nerves causing the pain and the spurs add to that pain. The cartilage is unable to repair itself.
There are primary and secondary joint diseases. Primary has no known cause other than wear and tear. The causes of the secondary are hip dysplasia, patella luxation (or loose kneecap), osteochondrosis, trauma, and ruptured knee ligaments. Sometimes this can be prevented by surgical repair of the joint. Read on for more detail of descriptions of secondary causes.
The ball and socket joints are malformed in hip dysplasia. The ball and socket do not fit together properly causing serious complications such as chronic inflammation, calcium build up, muscle pain and surrounding tissue breakdown. The larger breeds such as Labradors, Golden Retrivers, St. Bernards, Great Pyrenees, Siberian husky, and German Shepherds are most at risk, but even smaller dogs are at risk. A common cat breed that has hip dysplasia is Himalayan.
The loose knee cap or dislocated kneecap occurs when the leg bones are poorly formed. This causes the kneecap to move in and out of normal position sounding like a pop.
Poor breeding and/or improper diet result in cartilage deterioration accompanied by tissue inflammation and pain. This is called osteochondrosis.
Large breed dogs are known to hereditarily have elbow dysplasia. The malformed bones results in painful bone chips. The same occurs in knee dysplasia.
Dislocation of the knee can occur when the ligaments are torn causing instability. This is usually a result of poor breeding and causes inflammation.
Bone spurs can result from hypertrophic arthritis causing a lot of pain.
The cause of shoulder degeneration is not clear because it could be an unstable joint, osteochondrosis, trauma or a combination.
Similar to carpal tunnel in humans is wrist arthritis usually in very active pets.
Infection or underlying immune diseases cause inflammatory joint disease when large amounts of protein, white blood cells and fluid enter the joint. There is usually systemic illness such as a fever, anorexia and stiffness all over. Arthritis that is caused by infection can be due to bacteria, fungal infection, or a tick born disease such as Lyme disease. Arthritis that is caused by underlying immune diseases results from a weakened immune system which may be hereditary. Dogs rarely have a deforming type of immune arthritis called rheumatoid arthritis. Nondestructive joint infections can result from lupus and unidentified immune related arthritis. If treated improperly the infection can thrive.
What are the warning signs?
There are no warning signs because cartilage has no nerves. The joint will have severe damage and the fluid will be very thin causing inability to protect the bone before there are signs. This is why years of abnormal stress occur before the signs show.
What are the signs of arthritis?
Early signs of Arthritis are small including slightly less active and playful with the desire for shorter walks. As the progression continues some signs become more serious and are sad to see:
- Moving more slowly in any activity
- Difficulty getting up from resting
- Painful yelping when touched
- Personality change that avoids touch
- Reluctant to walk, climb, jump or play
- May refuse using stairs and jumping in the car
- Change in appetite
- Change in behavior
- Lagging behind
- May look for warm soft sleeping spot
- Noticeable weight shift to unaffected limbs
- Affected limbs will have muscle atrophy
- Some animals may have time without symptoms only to have the symptoms return the next time they get up. Cold, damp weather is known to increase the symptoms.
What are comfort measures and exercise tips?
A soft bed that is as comfortable as a human’s can help. An old mattress, crib mattress, 4 inch foam rubber or soft couch works well as long as they are raised about a foot off the floor. An orthopedic bed can reduce pressure on the joints and relieve pain. The cold damp weather flares the pain so a pet sweater or warmer house temperature (65-80 degrees) can help and keep the pets bed away from drafts and in a warm spot. Putting a ramp on outside stairs can make going outside easier. Larger breeds can benefit from elevated feeding and drinking bowls, as well.
Massage and physical therapy can help relax stiff muscles and increase range of motion. Physical therapy is as simple as flexing and extending the affected joint very gently. Focus on being slow and gentle without forcing while extending out in all directions three to four times per day. Following up with a massage can help. Start the massage by just petting the area and work up to gentle kneading of the muscle near the joint with fingertips in small circles working away from the joint. Also moist heat from a water bottle or soaked towel can help.
Gentle consistent exercise such as a walk around the block a few times every day, or a 10-30 minute walk three times a day is good for dogs. Just exercising on the weekends is not good. A young active dog should be restricted to walks on a leash. Playing catch with a frisbee is very hard on the joints. Swimming is the best exercise with minimal joint stress. Make sure to stop the exercise when the animal appears to slow down, pant and appear tired. If the arthritis is in the front legs avoid exercises that cause downward jumps. If the arthritis is in the back legs avoid jumping upward. Older dogs should refrain from jumping altogether. Never exercise your pet after a meal, as it can cause bloating, and serious health consequences can occur. The benefits of exercise include keeping the joints flexible and the muscles around the joints strong, preventing further deterioration of bone and cartilage, and improving their overall health and fitness.
Overweight animals are less likely to exercise and the extra weight flares the arthritis pain. More weight equals more pain for old joints. Being able to feel a dog’s ribs easily is a sign of proper weight. If this is not the case a light diet can help including no table scraps or fatty treats.