Definition
The metacarpophalangeal joint (Articulatio metacarpophalangealis pollicis) forms the transition from the metacarpus to the thumb. The joint allows the thumb to be bent and stretched. Pain in the metacarpophalangeal joint can become a burden in everyday life, since the thumb plays an important role in the execution of grasping movements.
Pain in the metacarpophalangeal joint of the thumb can have various causes such as trauma or arthrosis (joint wear and tear). Depending on the cause, the pain can vary and can be pulling, stabbing, pressing or very sudden during movement. If thumb pain is permanent or recurrent, a doctor should be consulted to clarify the cause of the pain in the metacarpophalangeal joint.
Causes
On the one hand, pain in the metacarpo-phalangeal joint of the thumb can be caused by violent impact (trauma), in which the joint is injured. On the other hand, the thumb is moved by a variety of muscles. If muscles or the associated tendons become inflamed, this can also cause pain in the joint.
Such an inflammation can occur with the so-called “cell phone thumb”, whereby the one-sided movement of the thumb can cause the tendons and, in addition to the metacarpophalangeal joint, the other joints in the thumb to become inflamed. Furthermore, arthrosis (joint wear and tear) can be the reason for pain in the metacarpophalangeal joint of the thumb. Here the joint cartilage wears off and causes painful movement restrictions.
At rest, the pain in the metacarpophalangeal joint of the thumb is usually not felt. Arthrosis in the metacarpo-phalangeal joint of the thumb can also be caused by a previous injury (trauma), for example, in which the joint or the bones were damaged. Another possible cause of pain in the metacarpophalangeal joint of the thumb can be the so-called rheumatoid arthritis (chronic polyarthritis).
This is a chronic inflammation in which other joints in addition to the metacarpophalangeal joint of the thumb can be affected. Gout can also be responsible for a painful metacarpophalangeal joint. Rheumatoid arthritis is a chronic inflammatory joint disease of unknown (idiopathic) origin.
It is an autoimmune disease in which the body’s immune system overreacts. In rheumatoid arthritis, the immune reaction is mainly directed against joints, but internal organs can also be affected. The immune reaction destroys the joints more and more, causing pain, swelling and redness.
The joints are usually affected symmetrically (i.e. on both sides of the body). Besides pain in the metacarpophalangeal joint of the thumb, the small finger joints are almost always affected. Additionally, the knee, hand, foot and cervical spine can be painful and inflamed.
In rare cases, arthrosis can also cause pain in the metacarpophalangeal joint of the thumb. Arthrosis is a degenerative wear and tear of cartilage in the affected joint. In contrast to rheumatoid arthritis, arthrosis of the metacarpophalangeal joint is not an inflammatory process.
Rather, arthrosis is caused by joint malpositions, heavy one-sided stress or increasing joint wear and tear with age. However, it is relatively rare that arthrosis in the metacarpo-phalangeal joint causes pain. Arthrosis of the thumb usually affects the thumb saddle joint or the thumb end joint.
Gout (arthritis urica) is a metabolic disease in which so-called urate crystals (uric acid salt) are deposited in the joints. These urate crystals can be caused by excessive consumption of meat and alcohol, for example. Thus, gout is primarily a disease of affluence, with most patients also suffering from diabetes mellitus, overweight (obesity), high blood lipid levels (hyperlipidemia) or high blood pressure (hypertension).
If an attack of gout occurs, embedded urate crystals can cause pain in the metacarpophalangeal joint of the thumb and other finger joints in addition to the most common localization in the big toe. Ligament injuries are another possible cause of pain in the metacarpophalangeal joint of the thumb. Strong violent impacts, for example in a sports accident, can lead to a kinking of the thumb in the metacarpophalangeal joint.
A frequent injury is the ski thumb. This results in a partial or complete tear of the ulnar collateral ligament of the thumb. Those affected suffer from painful swelling, bruising in the area of the metacarpophalangeal joint of the thumb and instability in the joint.Depending on the extent of the injury, conservative and surgical treatment methods may be considered.
In order to differentiate the cause of the pain in the metacarpophalangeal joint of the thumb, even physical symptoms can be groundbreaking. If there is general pain in movement or restrictions in movement with swelling and bruising, it may be a torn ligament or joint injury after an accident or trauma. Consideration of additional pain in other joints is important for finding the cause.
Pain in the metacarpophalangeal joint of the thumb can also be relieved by numbness or tingling. Gout can cause sudden and very severe pain in the metacarpophalangeal joint of the thumb. This does not necessarily mean that other joints are also affected.
Furthermore, the pain in the metacarpophalangeal joint of the thumb caused by gout can usually be felt at rest. If the pain in the metacarpo-phalangeal joint is caused by osteoarthritis, the pain is more likely to occur initially during movement and gradually improve. However, if the arthrosis is already well advanced, it can also lead to permanent pain.
In rheumatoid arthritis, pain in the metacarpophalangeal joint of the thumb is rather rare. On the other hand, there is usually bilateral (symmetrical) pain and swelling in the small finger joints and thumb saddle joint. Often a fist closure is only possible with difficulty and the thumb cannot be moved well in the direction of the little finger.
Affected patients feel the pain even at rest and usually complain of morning stiffness that lasts for more than half an hour. In addition, after a while so-called rheumatic nodules (nodes that can be felt under the skin) form. If, in addition to the pain at the base of the thumb joint, swelling also occurs, this is a sign of an inflammatory process with joint effusion.
Capsule and tendon injuries of the metacarpophalangeal joint of the thumb can also cause swelling and pain. In most cases, there is also a redness in addition to the swelling. In addition, the metacarpophalangeal joint of the thumb can only be moved to a limited extent due to pain and the obstructive swelling.
If, in addition to the pain in the metacarpo-phalangeal joint of the thumb, small, non-painful swellings occur, this can be so-called rheumatic nodules. These can occur on fingers, toes, hands and elbows and are signs of a rheumatic process. If there is pain on the inside of the base of the thumb joint, a so-called “ski thumb” can be the cause.
This is a tear of the inner collateral ligament at the metacarpophalangeal joint of the thumb. Such a tear is usually caused by the fall on the thumb, which is stretched outwards during the impact. After such trauma, signs of inflammation, swelling, pain and bruising occur.
The doctor can check the stability of the metacarpophalangeal joint of the thumb: If the joint is unstable, the joint can be “unfolded” outwards because the securing ligament has been torn. If the pain in the metacarpo-phalangeal joint is bilateral or symmetrical, it may be rheumatoid arthritis, as mentioned above. Although rheumatoid arthritis usually occurs on both hands in the thumb saddle joint, in rare cases it can also cause pain in the metacarpophalangeal joint.
Also, carpal tunnel syndrome, which causes constriction of the median nerve, can cause pain in the thumb on both sides. The pain can radiate into the metacarpophalangeal joint. In addition, pain in the middle and index finger is usually typical, sometimes accompanied by tingling and numbness.
