Musculoskeletal diseases: Osteoarthritis

Archived Content

Information identified as archived is provided for reference, research or recordkeeping purposes. It is not subject to the Government of Canada Web Standards and has not been altered or updated since it was archived. Please "contact us" to request a format other than those available.

Osteoarthritis

Osteoarthritis (OA) is a joint disease that mostly affects the cartilage (the slippery tissue that covers the ends of bones in the joint), although other joint structures may also be involved (e.g., the synovial fluid that provides lubrication to the joint and keeps the cartilage smooth). Over time, the cartilage can break down and wear away, causing the unprotected bone ends to rub against one another, resulting in the breakdown of the joint structure. This process may take decades, with the complete destruction of the cartilage occurring in end-stage OA. The symptoms of OA may start before there is damage to the cartilage. As OA progresses, there is increased pain or swelling, limitations in motion at the joint, stiffness, and/or the formation of bone spurs (tiny growths of new bone). OA can affect any joint, but usually affects the hands and weight-bearing joints such as hips, knees, and spine. This section will describe the implications for chronic osteoarthritis of the hand and the lower extremities (including OA of the hip and/or knee). The limitations associated with osteoarthritis of the spine are described and classified in the health state for chronic low back pain.

OA is the most common type of arthritis and is one of the leading causes of functional limitations in the elderly. It affects 10% of Canada’s population.⁴ Although the prevalence of OA is higher in men before age 45, and higher in women after age 55, men and women are equally affected when all ages are considered.^19,20 By the age of 70, OA is present in most people.^4,21 Symptoms, which involve the area around the joints, usually come on slowly and can range from mild to very severe. Deep, aching joint pain is the earliest symptom, with mild joint stiffness in the mornings. The pain is generally worse following use of the affected joint but can be relieved by rest; long periods of inactivity, however, can also result in increased stiffness that resolves with moving the joint. As OA progresses, joint motion diminishes and there is significant tenderness around the affected joint. The pain also worsens (initially the pain is only with use of the joint; over time the pain becomes constant, even at rest, and is worse at night, preventing sleep). These problems make it hard to move around and to do everyday tasks, such as opening a jar or walking up stairs. Despite these many challenges, however, most people with OA can lead active lives with proper management of the condition.

The exact cause of osteoarthritis is unknown, although it is associated with the aging process (it is also known as degenerative joint disease). However, OA is not a product of normal aging; rather, it is a product of exaggerated or accelerated aging (where the normal repair process becomes abnormal and fails to regenerate the cartilage normally). Degeneration of the joint may begin as a result of trauma to the joint or repetitive strain. Weight-bearing also plays a significant role; being overweight increases the risk of OA because it puts stress on joints such as hips and knees. Other risk factors include mechanical stress (repetitive high-impact activities or repetitive deep knee bending), endocrine and metabolic diseases, high bone-mineral density, and heredity (especially in OA of the hand). An initial diagnosis is made based on a physical exam and symptom history, and subsequently confirmed via x-rays. In addition, blood or joint fluid tests can sometimes be used to rule out other diseases although they are unable to verify the presence of OA.

Treatment focuses on decreasing pain and improving joint movement. Exercise helps reduce pain and improve function and can also help maintain a healthy weight, resulting in less strain on the joints. Range of motion exercises and muscle strengthening exercises will improve the muscles surrounding the joint, providing more stability. Rehabilitation techniques, including bracing and heat/cold applications, are also useful. Patient education of self-management strategies to learn how to cope with the pain and functional limitations are also important adjuncts to treatment that improve quality of life. Pharmacological treatment includes acetaminophen, NSAIDs, injection of cortisone into the joints, and nutritional supplements. Surgery is an option for those with damaged joints who have not benefited from other treatments and still have a significant level of pain or limitation in their ability to function in their daily life. In particular, joint replacement is an important and effective form of treatment for OA of the hip and knee.

Osteoarthritis of the hand(s)
ICD-9 code: 715.4

Description

Osteoarthritis of the hand affects the finger joints and the base of the thumb. This is the only form of the disease that seems to be hereditary. It is more prevalent in women than men, especially after menopause. Diagnostic criteria, developed by the American College of Rheumatology, require that hand pain, aching, or stiffness be present, as well as three or four other symptoms, which include hard tissue enlargement in a selected number of finger joints and the presence of deformity in at least 1 of 10 selected joints.²² Limited range of motion due to pain and stiffness result in some functional limitations, particularly in the use of hands and fingers. Household activities such as opening jars or washing dishes may be difficult. There is also the potential for (or presence of) significant deformity, which can promote further limitations.

Classification

3

2

1

3

Osteoarthritis of the lower extremities
ICD-9 code: 715.5 for pelvic region and thigh (hip OA)
ICD-9 code: 715.6 for lower leg (knee OA)

Description

Osteoarthritis of the lower extremities affects the hip(s) or knee(s), and often results in difficulties with certain movements, such as putting on socks or pants, kneeling, squatting, or going up or down stairs. The most common joint affected by OA is the knee. The American College of Rheumatology classification criteria for OA of the hip are presence of hip pain and at least two or three other features, such as limitations in internal rotation of the hip and periods of morning stiffness of 60 minutes or less.²³ Regarding OA of the knee, the criteria are the presence of knee pain and at least 3 other features, including morning stiffness lasting under 30 minutes, bone tenderness, and bone enlargement.²⁴ An additional criterion (for either diagnosis) is age older than 50 years. Regardless of the site affected, pain, limited range of motion and stiff, swollen joints in the lower extremities impair the ability to perform such tasks as walking, standing, or sitting. This results in limitations in both physical and social functioning. Moderate levels of pain and discomfort are also experienced. Initially, pain is only present with activities such as walking, bending, going up or down stairs, and standing, but over time, pain becomes constant. When pain is constant, it often affects sleep. Frustration and depression may develop as a result.

Classification

Archived Content

Health State Descriptions for Canadians 82-619-MIE