Metacarpophalangeal Joint Arthritis
What is metacarpophalangeal joint (MCP) arthritis?
It is arthritis of the knuckles, usually the knuckles of the thumb and index finger. The metacarpal bones are the bones of the hand. The finger bones are called phalanges. The MCP joint is the knuckle where the finger bone meets the hand bone. Arthritis is a leading cause of disability and the metacarpophalangeal (MCP) joint is a common site for arthritis of the hand, particularly in the elderly.
The thumb and index finger are important for grasping, pinching and gripping, picking up small objects and eating with one hand. This is known as opposable thumbs which means the thumb can be placed opposite the fingers on the same hand. Arthritis of the MCP joint can cause a person to drop objects, weaken the hands, and cause substantial pain and disability.
What causes MCP joint arthritis?
- Osteoarthritis (OA), also known as wear and tear arthritis, is mechanical arthritis. OA is localized in the joint causing inflammation in the joint, loss of the cartilage at the ends of the bones, pain and loss of mobility and function. It usually affects people over age 50.
- Post-traumatic arthritis is osteoarthritis that develops after an injury to a joint.
- Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder that affects the joint and other body areas including the skin, eyes, lungs and heart. RA causes changes to the ligaments and tendons. It erodes the joint and causes joint deformity. Rheumatoid arthritis affects patients of working age. Blood tests can help diagnose rheumatoid arthritis.
- Gout is a form of arthritis that is caused by creation of uric acid crystals that accumulate in the joint causing inflammation and extreme pain.
- Pseudogout is a type of arthritis caused by deposits of calcium phosphate crystals.
- Psoriatic arthritis is another type of arthritis that affects people with psoriasis.
What are the symptoms?
Pain, swelling and stiffness, trouble bending and straightening the joint, difficulty gripping and opening jars and twisting a doorknob. Pain with motion that progresses to pain at night and at rest. When the cause is RA, joint swelling and deformity
How is MCP joint arthritis diagnosed?
Your Ortho Illinois physician will evaluate your hands and assess range of motion, stability and tenderness of the joint. They will perform testing to distinguish the type of arthritis that is causing the problem by reviewing your medical history and symptoms. They may also rule out other conditions like tendonitis and nerve compression. Blood tests will be ordered to rule out RA, Gout, and Pseudogout.
X-rays will be ordered to confirm the diagnosis. When the cause is OA, x-rays will show a narrowing of the space between the bones indicating the loss of cartilage. Additional imaging tests may also be recommended.
What are the treatment options for MCP joint arthritis?
The goal of treatment is to improve function and reduce pain. Your treatment options will vary depending on the type of arthritis, and the amount of pain and dysfunction you have. Some new disease modifying drugs are available to treat rheumatoid arthritis and psoriatic arthritis.
A variety of nonsurgical options have been shown to be effective including activity modification, topical and oral anti-inflammatory medications, splinting and cortisone injections. A new drug to treat arthritis pain, called diclofenac sodium, is a topical anti-inflammatory medication, now available over the counter. Physical therapy can help you regain or maintain motion and strength. When nonsurgical options fail to improve your condition, joint replacement will be recommended.