Metacarpophalangeal (MP) Joint Arthritis: Causes, Diagnosis, and Treatment
The metacarpophalangeal (MP or MCP) joints are large joints at the base of each finger. These complex hinge joints play an important role in both power grip and pinch activities.
Causes of Metacarpophalangeal Joint Arthritis
The MP joints are less commonly affected by arthritis than smaller hand joints or the joints where the thumb meets the wrist (CMC). However, several conditions can affect the MP joints, including:
- Rheumatoid arthritis: The most common arthritic condition affecting the MP joints. It causes inflammation of the joint lining (synovium), leading to cartilage and soft tissue destruction, resulting in ulnar drift of the fingers toward the little finger.
- Post-traumatic arthritis: Occurs after injury, leading to gradual loss of cartilage and progressive pain and stiffness.
- Osteoarthritis: A form of arthritis that affects the MP joints, causing pain and stiffness, particularly in the thumb, index, and middle fingers.
- Gout, psoriasis, and infection: Less common causes of MP joint arthritis.
Diagnosis of Metacarpophalangeal Joint Arthritis
The symptoms of MP joint arthritis vary based on the underlying cause:
- Rheumatoid arthritis: Characterized by pain, swelling, and deformity in multiple joints, with an ulnar drift of the fingers and loss of motion, especially in extending (straightening) the fingers.
- Osteoarthritis and post-traumatic arthritis: Involves deep, aching joint pain, particularly with grip and pinch activities. Swelling, especially between large knuckles, may also be present.
The doctor can confirm the presence of MP arthritis through x-rays, and special x-rays may be necessary to assess the metacarpal head in milder cases.
Treatment Options for MP Arthritis
There are various treatment options depending on the severity of joint destruction and the symptoms experienced:
- Rheumatoid arthritis: Medications to combat the inflammatory process are typically the first line of treatment. If medications are ineffective, synovectomy (removal of the inflamed synovium) may be considered to slow the destructive process and preserve cartilage.
- Post-traumatic arthritis: Anti-inflammatory medications, activity modification, and splints may offer relief. If symptoms worsen, surgical treatment may be necessary.
MP Joint Fusion or Replacement
For severe joint destruction, patients may benefit from joint fusion or replacement. Key options include:
- Joint fusion: While effective for the thumb, joint fusion can result in a loss of motion in the fingers.
- Joint replacement: Typically preferred over fusion, especially in younger or more active patients.
- Salastic hinged implants: Provide reasonable pain relief and are often used in older, less active patients.
- Advanced implants: Newer implants that replicate joint surfaces may offer improved outcomes for younger, more active individuals.
If you’re suffering from metacarpophalangeal joint arthritis, make an appointment with South Florida Hand and Orthopaedic Center.