What is the difference between primary and secondary osteoarthritis

Osteoarthritis (OA) is a form of arthritis where joint cartilage breaks down. Primary OA has no clear cause. Secondary OA, however, occurs as a result of an existing medical condition, joint injury, or abnormality.

Primary and secondary OA are the same condition, but they have different causes.

OA can affect various joints in the body and may cause pain, stiffness, and limited range of motion.

In this article, we look at the symptoms and causes of secondary OA. We also discuss treatment options and outlook for people with the condition.

According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), OA is the most common type of arthritis, and it usually affects older adults.

OA is a joint condition where joint cartilage breaks down. It can develop in any joint in the body, but it usually affects the:

• fingers
• neck
• lower back
• hips
• knees

The NIAMS states that symptoms of OA can vary from mild to severe and may include:

• joint pain, which may get worse at night
• stiff joints, which may occur after periods of rest or after sleeping
• limited range of motion in the affected joint
• swelling around the joint, which may worsen after activities that require using that joint
• a loose or unstable-feeling joint

People may have primary or secondary OA. Both conditions have the same symptoms, but the causes differ.

Primary OA has no clear cause. By contrast, secondary OA occurs due to an existing medical condition, abnormality, infection, or injury.

Causes of secondary OA may include:

• an existing joint abnormality
• injury or trauma to the joint
• a joint condition present from birth
• inflammatory arthritis
• infectious arthritis
• osteoporosis
• avascular necrosis, where bone tissue dies from a lack of blood supply
• osteochondritis dissecans, where bone underneath joint cartilage dies due to a lack of blood supply
• Paget’s disease
• metabolic disorders
• hemoglobinopathies, which are conditions affecting red blood cells
• Ehlers-Danlos syndrome
• Marfan syndrome

Treatment for secondary OA aims to relieve pain, reduce stiffness, and increase range of motion and joint function. It may also help prevent the condition from progressing.

Treatment options include:

Exercise

Research shows that a combination of aerobic and resistance exercises can help reduce pain and improve physical function.

Exercise can also help strengthen muscles, increase endurance, and improve flexibility. An exercise program for OA may include:

• stretching exercises to improve range of motion
• using weights or exercise bands to strengthen muscles, which then helps better support joints
• doing exercises to help promote balance and agility, which can help people maintain everyday activities
• exercising in water to reduce stress on joints or engaging in other low impact activities, such as walking, tai chi, or cycling

People will need to avoid any activities that worsen their symptoms or put extra strain on the joints.

Losing excess weight

Losing excess weight can help reduce stress on the joints.

In people with knee OA, losing 1 pound (lb) of body weight may relieve 4 lb of pressure exerted on the knees.

Losing excess weight may also help:

• relieve pain and improve physical function
• decrease inflammation
• slow down progression of OA and cartilage breakdown

Joint support

Devices such as braces, splints, and walking canes may help stabilize the joints and relieve extra pressure.

Moreover, if joints are out of alignment, corrective devices, such as orthotics or knee braces, may help.

Medications

Certain medications may help alleviate pain and reduce inflammation. These may include:

• oral pain relief and anti-inflammatory medications
• topical ointments to apply to affected joints to relieve pain
• corticosteroids, which a doctor may inject into the joint to ease pain
• for knee OA, hyaluronic acid injections into the knee to aid joint lubrication
• oral selective serotonin and norepinephrine reuptake inhibitors for long-term pain

Surgery

If other treatments are ineffective, a person is experiencing severe joint damage, or OA is negatively affecting the person’s day-to-day life, surgery may be necessary.

In an osteotomy, a surgeon will remove a piece of bone close to the damaged joint in order to shift weight away from that joint.

Another surgical option for OA is partial or total joint replacement, depending on the extent of damage to the joint. This involves removing part or all of the joint to replace it with an artificial one made from plastic, ceramic, or metal.

Risk factors for secondary OA include:

• being over the age of 50 years
• having had a bone fracture, ligament or cartilage tear, or other joint injury
• overly using the same joints, which may happen as a result of certain occupations or sports
• having obesity, as excess body weight can put extra stress on joints and increase inflammation
• having an abnormal joint structure or unusually aligned bones
• having muscle weakness
• being female
• having a family member with OA

The outlook for OA can vary from person to person and will depend on which joints the condition affects, the severity of symptoms, and level of physical function.

In some individuals, OA may be mild, and a person may be able to effectively manage their symptoms with treatment.

In other cases, people may experience severe disability due to OA. Joint replacement surgery may be the best long-term solution for some individuals with severe OA.

OA is a joint condition where joint cartilage breaks down, causing pain, stiffness, and limited rage of motion in the joints.

Primary OA has no clear cause, while secondary OA is due to an existing condition, injury, or infection.

Treatment may help relieve pain, reduce inflammation, and prevent progression of the condition.

Treatment options may include exercise, excess weight loss, support devices, and medications. In some cases, people may require surgery to reduce stress on a joint or to replace a damaged joint.