Metacarpophalangeal Joint Arthritis

What is Metacarpophalangeal (MCP) Joint Arthritis?

The bones of the hand are called metacarpals and the bones of the fingers are called phalanges. The metacarpophalangeal joint or MP joint, also known as the first knuckle, is the large joint in the hand where the finger bones meet the hand bones. The MCP joint acts as a hinge joint and is vital during gripping and pinching. When arthritis affects the MP joint, the condition is called MP joint arthritis. The condition is more common in the thumb joint and index finger joint.

Causes of Metacarpophalangeal (MCP) Joint Arthritis

Causes of MCP joint arthritis include but are not limited to:

• Inflammation (mainly rheumatoid arthritis)
• Traumatic injury leading to broken bone or loss of cartilage (post-traumatic arthritis)
• Routine wear and tear of the MCP joint (osteoarthritis)
• Certain medical conditions (gout, pseudogout, psoriasis, etc.)
• Infections (after a cut, puncture or animal bite)

What are the Signs or Symptoms of Metacarpophalangeal (MCP) Joint Arthritis?

MCP joint arthritis can present with several symptoms such as:

• Pain that worsens during gripping and pinching activities
• Stiffness, swelling, deformity, and limited motion 
• Feeling of weakness when trying to use the hand
• Shifting of fingers toward the pinkie (little finger) over time
• Joint pain at rest and at night in the advanced stages
• MCP joint that appears larger than normal

What if Metacarpophalangeal (MCP) Joint Arthritis is Left Untreated?

The condition, if left untreated, may result in considerable MCP joint pain, loss of motion and disability.

How is Metacarpophalangeal (MCP) Joint Arthritis Diagnosed?

Your doctor may evaluate the affected hand and MCP joint and assess for tenderness, range of motion, and stability of the joint. A plain X-ray or other imaging studies may be taken for further validation. Blood tests or imaging studies may also be ordered to fully confirm the diagnosis.

How is Metacarpophalangeal (MCP) Joint Arthritis Treated?

Several nonsurgical treatment options are available and known to be effective in controlling symptoms of mild-to-moderate MCP joint arthritis. However, the appropriate treatment depends on the amount of pain and loss of function. They include:

• Activity modification or hand therapy
• Anti-inflammatory medications (oral or steroid injections)
• Cortisone injections (if medication fails)
• Simple splinting or flexible strapping
• Topical skin creams

If the condition is severe and nonsurgical treatments fail, your doctor may consider the surgical option. The optimal surgical procedure will depend on the type of arthritis, severity, and functional needs of the patient.  The most common surgical options can be any of the following.

• Arthroplasty:  Joint or bone replacement with silastic hinged or silicone or metal implants. This procedure is a popular option for fingers except for the thumb.
• Arthrodesis: This involves surgical fusion of the knucklebones and immobilisation of the joint. It is a reliable and generally followed procedure for the thumb.
• Synovectomy: The inflamed joint lining (synovial tissue) is removed arthroscopically, and the extensor tendons are realigned.