What are the main causes of common joint disorders?

Joint disorders are medical conditions or injuries that affect the joints, which are the points where two or more bones meet in the body, such as the shoulders, elbows, hips, knees, and finger joints. These disorders also involve the soft tissues surrounding the joints, such as cartilage, tendons, and ligaments. These conditions can result from a variety of causes, ranging from acute and chronic injuries to inflammatory diseases and autoimmune conditions.

Joint Injuries

Injuries are one of the common causes of joint disorders and can occur in two main ways:

• Sudden Injuries: These occur due to accidents or sports injuries. Examples include joint sprains, where the ligaments connecting bones are stretched or torn to maintain joint stability [1]. They also include acute strains that happen when muscles or tendons are suddenly stretched or torn, such as from lifting a heavy object [1]. A joint dislocation, where bones are forced out of their normal position, is a medical emergency that requires immediate medical attention [1].
• Overuse Injuries: These injuries occur when a joint is repeatedly stressed through repetitive motions, leading to damage in the soft tissues surrounding the joint [1]. Examples include bursitis, where the fluid-filled sacs that act as cushions between bones and moving parts around a joint become swollen [1]. This also includes tendinitis, which occurs when tendons are overused, causing them to swell and leading to pain when moving the joint [1].

Inflammatory and Degenerative Diseases

Many diseases that affect the joints are chronic and may cause pain, stiffness, redness, and swelling [1]. The most notable of these diseases include:

• Arthritis: This is a general term that encompasses many types that cause pain and swelling in the joints [1].
• Osteoarthritis: This is the most common type of arthritis [1]. It occurs when the cartilage covering the ends of the bones in a joint is damaged, leading to the bones rubbing against each other and wearing down over time [2]. Joint injury at an early age or being overweight can increase the risk of developing osteoarthritis later in life [2].

Autoimmune Diseases

In some cases, the body's immune system attacks its own healthy tissues by mistake, leading to joint disorders [2]. Examples of these diseases include:

• Rheumatoid Arthritis: An autoimmune disease where the immune system attacks healthy joint cells, causing pain and swelling [2].
• Lupus: An autoimmune disease that affects multiple parts of the body and can cause joint and muscle pain, often leading to arthritis [1].
• Sjögren's Syndrome: An autoimmune disease that affects the moisture-producing glands in the body; its main symptoms include dry eyes and mouth, and it often causes joint pain [1].

Genetic Factors and Congenital Deformities

In some cases, joint disorders may be linked to genetic factors or congenital deformities. For example, Distal arthrogryposis type 1 (Arabic) is a genetic disorder characterized by joint deformities that limit movement in the hands and feet, and it is believed to be caused by mutations in genes that affect the contraction of muscle fibers [3].

When Should You See a Doctor?

You should consult a doctor if you experience severe joint pain, swelling, numbness, or an inability to bear weight on the joint [1]. You should also visit a doctor if pain from an old injury worsens with increased swelling or joint instability [1]. Treatment depends on the underlying cause of the disorder and may include medication, physical therapy, and, in some cases, surgical intervention [1].

Medical references

• Joint Disorders
• Health Lesson: Learning About Joints
• Distal arthrogryposis type 1: MedlinePlus Genetics