Brief overview
- Treatment: Mainly symptomatic, conservative with pain medication, sparing of the joint by splints and the like; injections of cortisone and hyaluronic acid; various surgeries up to joint replacement
- Symptoms: pain when grasping; increasing immobility of the thumb; grinding and rubbing in the joint
- Causes and risk factors: Age-related wear and tear, overuse and incorrect use, hormonal changes in women, often unclear cause; secondary osteoarthritis due to previous injuries or diseases of the joint
- Diagnosis: Medical history, physical examination, grind test, X-ray examination
- Prognosis: rhizarthrosis is not curable; conservative therapy as well as surgery alleviate pain and ensure preservation of joint mobility
- Prevention: Avoid overloading and incorrect loading; use work techniques that are gentle on the joint; heal and cure injuries and diseases properly
What is rhizarthrosis?
In rhizarthrosis, the thumb saddle joint is worn. This joint sits at the base of the thumb near the wrist. It connects the great polygonal bone (a carpal bone) to the first metacarpal bone. This metacarpal is then connected to the first of the two phalanges of the thumb by a joint.
If you want to learn more about joint wear and tear, please read the article Osteoarthritis.
Treatment
The doctor first tries to treat rhizarthrosis with conservative measures. If that does not help, surgery may be considered.
Conservative therapy
Each patient receives an individual therapy. It depends on how badly the joint is damaged and how much it hurts.
To stabilize and relieve the diseased thumb saddle joint, doctors often advise patients to wear a splint (orthosis). For example, there are splints made of plastic or metal. Some patients also use a bandage made of leather that covers the wrist and thumb.
For the pain, the doctor often prescribes painkillers from the group of non-steroidal anti-inflammatory drugs (NSAIDs). Patients apply these locally (for example, as an ointment) or take them as tablets. You should discuss with your doctor which painkiller is most suitable in each individual case and how long it should be used.
If the osteoarthritis thumb becomes inflamed, the doctor may inject glucocorticoids (“cortisone”) directly into the joint. They have a strong anti-inflammatory effect, but can only be administered for a short time.
In some cases, the doctor also administers hyaluronic acid into the joint. In many cases, this relieves the pain, at least for a limited time.
You can learn more about conservative therapies for joint wear and tear in the article Arthrosis.
What is the course of rhizarthrosis surgery?
In the case of advanced rhizarthrosis, conservative therapy measures sometimes no longer help. In such cases, surgery is often the only way to relieve the pain and restore the function of the thumb.
The doctor decides individually for each patient which surgical procedure makes the most sense. In most cases, he performs a so-called trapezium resection: In this procedure, he removes the greater polygonal bone (Os trapezium), the carpal bone below the thumb. The resulting gap can be stabilized with a strip of tendon (suspension plasty). He often uses part of the abductor tendon of the thumb for this purpose.
In addition, there are other surgical procedures that can be used for an “arthritic thumb”: For example, the joint can be stiffened (arthrodesis). This helps against the pain, but also makes the thumb less mobile.
In addition, in cases of pronounced rhizarthrosis, there is the possibility of inserting an artificial joint (endo prosthesis).
Another option of surgery is to cut the pain-conducting nerve branches from the thumb saddle joint, which leads to pain relief or even relief.
Symptoms
Rhizarthrosis causes pain, especially during grasping and twisting movements. For example, when patients turn a key in a lock or open the lid of a screw jar. Often the pain is so severe that these movements are no longer possible and the thumb can only be moved to a limited extent.
Many patients experience pain when they press on the area between the thumb and wrist. They also feel that their thumb saddle joint is powerless and unstable. Some also feel a rubbing or grinding sensation when they rotate their thumb.
In rhizarthrosis, as with osteoarthritis in general, physicians distinguish four stages:
- Stage I: The joint cartilage still looks smooth and relatively healthy, but is thickened and structurally altered. Possibly widened joint space (due to effusion).
- Stage II: The joint space is narrowed. Free joint bodies smaller than 2 millimeters may be seen. Bony extensions are present (osteophytes).
- Stage III: A clear narrowing of the joint space can be seen. Osteophytes are present. The free joint body is larger than 2 millimeters. The bone shows compaction (subchondral sclerosis).
For more on the general symptoms of joint wear and tear, see the article Osteoarthritis Symptoms.
Causes and risk factors
Rhizarthrosis can also be divided into a primary and a secondary form. The cause of primary rhizarthrosis is unexplained in many cases (ideopathic). However, since it occurs mainly in women after menopause, hormonal factors are discussed. In addition, incorrect and excessive loading of the joint is assumed to be one of probably several causes.
Secondary rhizarthroses occur as a result of an injury. For example, due to a bone fracture in the thumb saddle joint (Rolando fracture or Bennet fracture). If the fracture heals poorly, it is possible for the thumb saddle joint to become roughened and worn. This is when rhizarthrosis develops.
Diseases such as rheumatoid arthritis are also possible causes of secondary rhizarthrosis.
Examination and diagnosis
The complaints that the patient describes usually already arouse the doctor’s suspicion of rhizarthrosis. The doctor then examines the thumb saddle joint area more closely and palpates it. In the case of arthrosis of the thumb saddle joint, the area is painful from pressure.
The physician confirms the diagnosis by means of an X-ray examination: In the case of rhizarthrosis, the joint space narrows and the bone tissue below the joint cartilage becomes denser (subchondral sclerosis). These changes are clearly visible on the X-ray.
The X-ray findings say nothing about the extent of the symptoms!
Sometimes only a few signs of osteoarthritis are visible on the X-ray, but the patient still has pain. In other cases, the X-ray shows severe signs of wear, but the patient has little discomfort.
Is a person with rhizarthrosis unable to work?
Like all osteoarthritis, rhizarthrosis is usually not curable. However, in many cases, conservative therapy such as range-of-motion exercises can relieve the pain and keep the thumb mobile. In some cases, occupational therapy helps to cope better with the restriction in everyday life.
Whether and how rhizarthrosis affects the ability to work on a possible occupational disability or even severe disability depends on the individual case, the activity and the severity of the symptoms. In principle, recognition as an occupational disease is also possible, depending on the case.
After an operation, a period of rest and rehabilitation is often necessary, lasting several weeks or even months, depending on the case.
Prevention
To prevent secondary rhizarthrosis as a result of an injury or disease, it is important to heal and cure it properly. Rehab measures may be helpful in this regard.
