Metacarpophalangeal Joint Arthritis

At the base of each finger, there are large joints in the hand known as the matacarpophalangeal (MP or MCP) joints. They act as complex hinge joints and are important for both pinch and power grip activities.

The MP joints are not affected as much by arthritic conditions as the smaller joints in the hand, or the joint where the thumb joins the wrist (CMC). Rheumatoid arthritis is the most common arthritic condition affecting the MP joints. When this occurs, the joint lining (synovium) produces chemical factors that inflame and destroy the cartilage and soft tissue, such as tendons and ligaments. The final result is that the joint surfaces are destroyed and the fingers drift into a characteristic "ulnar-deviated" position (in which fingers begin to point toward the little finger).

Though it is less common, other conditions can produce pain, deformity, and motion loss. A gradual loss of joint cartilage (post-traumatic arthritis) with progressive pain and stiffness, can result from previous injuries. Similar symptoms are seen with osteoarthritis. Osteo-arthritis and post-traumatic arthritis commonly affect the thumb, index, and middle fingers, and the amount of deformity is often less severe than in rheumatoid arthrosis. Psoriasis, gout, and infection are other less common causes of MP joint arthritis.

Diagnosis

The majority of patients with rheumatoid arthritis have longstanding pain, swelling, and deformity in multiple joints of both lower and upper extremities. They usually have a characteristic ulnar drift of their fingers along with loss of motion, especially extension or straightening of the fingers.

Patients who have osteoarthritis and post-traumatic arthritis, usually complain of deep, aching joint pain that is worsened by pinch and grip activities. A lot of these patients will not have an obvious finger deformity, although swelling, especially in the spaces between the large knuckles, is usually present.

A diagnosis is usually confirmed by either plain x-rays or special x-rays to look more carefully at the matacarpal head, particularly in milder cases.

Treatment

Based upon the degree of the joint destruction and the patient's complaints, there are various treatment alternatives available.

If you have rheumatoid arthritis, there are a variety of medications that are very effective in combating the generalized inflammatory process. Consulting with rheumatologists who specialize in treatment of these disorders can be very helpful. If medication does not reduce these symptoms or slow down the destructive process, direct cortisone injections used judiciously can offer temporary improvement.

If you have post-traumatic arthritis, sypmtom relief is often provided from:

• Anti-inflammatory medications

• Activity modification

• Simple splints

In cases of deformity, progressive pain, and motion loss despite medical management, certain patients may be candidates for surgical treatment.

If you have rheumatoid disease, and are at a stage without any significant joint surface destruction, you may benefit from synovectomy. In this procedure, the active, inflamed lining tissue of the joint (the joint synovium) is removed in order to slow down the destructive process and maintain joint cartilage. At this time, the soft tissues (ligaments and tendons) can be tightened and re-aligned as needed in order to improve function.

Patients with severe joint destruction may benefit from either a joint replacement or joint fusion. The thumb functions very well after an MP joint fusion. In the fingers, however, the loss of motion can be very disabling and joint replacement is normally preferred. Replacement with silastic hinged implants has resulted in reasonable pain relief and function.

Complications following joint replacement surgery may include:

• Infection

• Implant loosening or dislocation

• Implant breakage

In older, more sedentary patients with low demand on the use of their hands, silastic implants have been particularly successful. Younger individuals and patients with more active, vigorous lifestyles, may benefit from more recent types of implants that try to replicate the joint surface. Continued research is being conducted to even further improve joint replacement and reconstruction in the hand.

For more information about simple, safe, and effective treatments for Metacarpophalangeal Joint Arthritis, or any other conditions of the hands or upper extremities, schedule an appointment with Dr. Sagini by calling 239-337-2003.