Rhizarthrosis or osteoarthritis of the trapeziometacarpal joint (TMC) is the wear and tear and destructuring of the joint at the base of the thumb. It is a pathology that occurs very frequently in the adult population, especially in women over 50 years of age.
Causes of rhizarthrosis
The morphology of this joint gives it great mobility in all axes of space (flexion, extension, abduction, adduction and opposition), which is essential to develop all the manual functions required in our activities. The constant functional demand of this joint generates continuous mechanical loads, which are greater the more manual effort is made. The pressures exerted on their articular surfaces are the environmental factor that favors the wear of their cartilaginous coating over the years, and therefore there is a clear direct relationship with the type of activity performed throughout life. For example, a person who in his job has to repetitively perform a grip between the index finger and thumb in a sustained or repetitive manner will probably develop rhizarthrosis over the years.
There is also a genetic factor that predisposes to its development, and therefore rhizarthrosis also occurs in people who have never worked performing repetitive efforts or activities with their hands.
The progressive disappearance of the articular cartilage provokes a local chronic inflammatory response typical of osteoarthritis in both the subchondral bone and the synovial membrane that surrounds the joints, causing the onset of osteoarthritic pain.
Symptoms of osteoarthritis of the thumb
Rhizarthrosis presents with pain at the radial margin of the wrist over the TMC joint. In the beginning, the pain is associated with certain efforts and/or movements of the thumb, although later it can exist even at rest and interrupt sleep.
A bony deformity progressively develops at the base of the thumb associated with limiting local stiffness and swelling. The perception of stiffness and local swelling often worsens with the intensity of manual activities performed.
Treatment options for rhizarthrosis
The first therapeutic strategy to control pain is the use of oral analgesic and anti-inflammatory medication. The use of specific splints for immobilization of the TMC joint usually favors pain control, and initially it may be useful to use them during night rest.
The infiltration of corticosteroids into the joint is an alternative that offers good results in terms of pain control for variable periods of time, so it can be considered as the second therapeutic step. Joint infiltrations of hyaluronic acid can also be performed as a preliminary step to more aggressive treatments.
When the pain and functional limitation experienced by the patient interfere in the development of daily activities, despite having carried out the above treatments, surgical treatment should be considered. Surgery comprises a wide range of alternatives, which in summary and from less to more invasive techniques consist of:
- Arthroscopic treatment in initial stages (cleaning and joint debridement).
- Removal of part of the trapezium bone (by open or arthroscopic surgery).
- Total removal of the trapezium with or without the interposition of a tendon or a prosthetic spacer.
- Removal of the trapezium with a ligamentous reconstruction with a tendon
- Interposition of a total joint prosthesis
Outcome of surgery for rhizarthrosis
Surgical techniques generally have a favorable outcome for pain control and recovery of thumb mobility. It can be performed with an incision between 3 and 4 cm in length. In younger patients who need a faster functional recovery and to avoid a loss of strength in the thumb, the use of a total prosthesis is recommended.
The choice of the surgical technique that each patient needs in his TMC joint depends, broadly speaking, on his age, the degree of osteoarthritis in the X-ray, the existing bone deformity, the required functional level and the coexistence of other diseases. Therefore, a personalized evaluation of each case by the orthopedic specialist is essential, as well as planning the surgical treatment individually according to each patient’s situation.