The hip is one of the largest weight-bearing joints in the body. When it’s working properly, it lets you walk, sit, bend, and turn without pain. Unlike the shoulder, the hip sacrifices degree of movement for additional stability. To keep it moving smoothly, a complex network of bones, cartilage, muscles, ligaments, and tendons must all work in harmony.
The hip is a ball-and-socket joint where the head of the femur articulates with the cuplike acetabulum of the pelvic bone. The acetabulum fits tightly around the head of the femur. The ball is normally held in the socket by very powerful ligaments that form a complete sleeve around the joint (the joint capsule). The capsule has a delicate lining (the synovium).
The head of the femur is covered with a layer of smooth cartilage which is a fairly soft, white substance. The socket is also lined with cartilage. This cartilage cushions the joint, and allows the bones to move on each other with very little friction.
An x-ray of the hip joint usually shows a “space” between the ball and the socket because the cartilage does not show up on x-rays.
What is arthritis?
The term arthritis literally means inflammation of a joint, but is generally used to describe any condition in which there is damage to the cartilage. Inflammation is the body’s natural response to injury. The warning signs that inflammation is present are redness, swelling, heat and pain.
The cartilage coats the joint surfaces to absorb stress, and allow smooth joint movement. The proportion of cartilage damage and synovial inflammation (the lining and fluid in the joint capsule) varies with the type and stage of arthritis. Usually the early pain is due to inflammation. Later in the disease, pain is from the irritation of the worn joint structures and inability of the joint to move properly.
What are the different types of arthritis?
There are over 150 different types of rheumatic diseases. e.g., Osteoarthritis, Rheumatoid Arthritis. Osteoarthritis is the most common form of arthritis. It is often referred to as wear and tear arthritis as it involves the thinning and breakdown of the cartilage lining, which cushions and protects the joints, where two bones meet. The bone may lose shape and thicken at the ends or produce bony spurs. It causes pain in the joints and surrounding soft tissues and limits the range of movement of a joint. Osteoarthritis affects many joints including the large, weight bearing joints of the hips and knees and also the spine, hands, feet and shoulders. There are several reasons for the development of osteoarthritis including age, being overweight, heredity factors, and joint damage from a previous injury or during early development of a joint. The severe pain of osteoarthritis can be very fatiguing and disabling.
This is an auto-immune disease in which the body’s immune system (the body’s way of fighting infection) attacks healthy joints, tissues, and organs. Occurring most often in women of childbearing age (15-44), this disease inflames the lining (or synovium) of joints. It can cause pain, stiffness, swelling, and loss of function in joints. When severe, rheumatoid arthritis can deform, or change, a joint.
Rheumatoid arthritis affects mostly joints of the hands and feet and tends to be symmetrical. This means the disease affects the same joints on both sides of the body (like both hands and both feet) at the same time and with the same symptoms. No other form of arthritis is symmetrical. About two to three times as many women as men have this disease.
Fibromyalgia is a condition associated with generalised muscle pain and fatigue. It is often described as a form of “soft tissue rheumatism”, which means it is a condition that causes pain and stiffness around the joints and in muscles and bones. It does not cause inflammation.
Gout is a form of arthritis. The joints appear painful, tight and swollen. The pain is caused by needle shaped microcrystals which can destroy the joint cartilage. When a person has gout, they have higher than normal levels of uric acid in the blood. The body makes uric acid from the foods we eat. Too much uric acid causes deposits, called uric acid crystals, which form in the fluid and lining of the joints. If the kidneys don’t work properly, then you can’t get rid of the uric acid in the urine as you should. The result is an extremely painful attack of arthritis. People often inherit gout and although we don’t know why, Maori and Pacific island peoples are more likely to get gout. The joint most commonly affected is the big toe.
Infectious arthritis can be caused by an infection, either bacterial or viral. When this disease is caused by bacteria, early treatment with antibiotics can ease symptoms and cure the disease.
Reactive arthritis this is arthritis that develops after a person has an infection in the urinary tract, bowel, or other organs. People who have this disease often have eye problems, skin rashes, and mouth sores.
Systemic lupus erythematosus
Systemic lupus erythematosus also called lupus or SLE is a form of arthritis which affects joints, muscles and other parts of the body. It is one of the autoimmune rheumatic diseases. In people with autoimmune diseases, antibodies are produced which act against certain body tissues and cause inflammation. There are two main form of Lupus: Discoid Lupus which affects only skin, and Systemic Lupus which involves the joints and sometimes the internal organs as well. Lupus (Latin for wolf) takes its name from the fact that it can cause serious rashes across the cheeks and nose (rather fancifully resembling the face of the wolf)
Ankylosing spondylitis is a term used to describe a form of arthritis that mainly affects the joints of the spine. However it may affect other parts of the body, e.g. hips, shoulders, knees or ankles. It causes inflammation outside the joint where the ligaments and tendons are attached to the bone, whereas in most forms of arthritis the inside of the joint is inflamed. It usually affects the little joints between the vertebrae of the spine and tends to diminish the movement which takes place at these joints. It affects younger people, teenagers to mid-thirties and more men than women.
Juvenile rheumatoid arthritis
Juvenile rheumatoid arthritis is the most common type of arthritis in children; this disease causes pain, stiffness, swelling, and loss of function in the joints. A young person can also have rashes and fevers with this disease.
Polymyalgia rheumatica, which means rheumatic pain in many muscles, results in severe stiffness and pain in the muscles of the neck, shoulders, lower back, buttocks and thighs. Other symptoms may be fatigue, loss of weight, night sweats and fever. Visual disturbance may indicate temporal arteritis or Giant cell Arteritis.
Polymyositis causes inflammation and weakness in the muscles; this disease can affect the whole body and cause disability.
Psoriatic arthritis is an inflammatory arthritis associated with psoriasis, a chronic skin and nail disease. Psoriatic arthritis affects about 10% of people with psoriasis. It can affect single joints, usually of the fingers or toes, as well as wrists, knees, ankles and sacro iliac joints of the spine.
This condition involves inflammation of the bursa, small, fluid-filled sacs that help reduce friction between bones and other moving structures in the joints. The inflammation may result from arthritis in the joint or injury or infection of the bursa. Bursitis produces pain and tenderness and may limit the movement of nearby joints.
Also called tendonitis, this condition refers to inflammation of tendons (tough cords of tissue that connect muscle to bone) caused by overuse, injury, or a rheumatic condition. Tendinitis produces pain and tenderness and may restrict movement of nearby joints.