The thumb of the human hand, much more advantageous than that of the primate, is completely opposable to the other four fingers and allows a precision gripper to manipulate objects of different sizes.
This evolutionary advantage means that there is a daily use of the hand and, consequently, a greater predisposition to suffer a joint degeneration of the trapeziometacarpal joint known as osteoarthritis of the base of the thumb or rhizarthrosis.
The aforementioned rhizarthrosis affects postmenopausal women more prevalently, the ratio with respect to men being 1/10. Thirty percent of them are bilateral. Among the causes of osteoarthritis at this level, the most frequent are: joint overuse, genetic predisposition, hormonal factors and hyperlaxity.
Only one third of rhizarthroses are clinically significant and the patient requires medical assistance, medication and, occasionally, incapacity for work. When advanced, it can constitute an important limitation of the functional capacity of the hand, in addition to producing pain, instability, deformity and loss of mobility.
Treatment is initially conservative, based on analgesics and chondroprotectors, in addition to occupational therapy for better use of the hand, hyaluronic acid injections (initial stages) and the use of corrective orthoses.
When the usual treatment fails, each case must be individualized according to age and degree of osteoarthritis. There is a wide range of possibilities, from minimally invasive surgeries such as trapeziometacarpal arthroscopy to arthrodesis in manual strength workers, trapeziometacarpal arthroplasty and interposition suspension arthroplasty. It should be noted that such a specialized part of the hand requires a very demanding treatment, always looking for the least invasive and aggressive surgical techniques, with which good clinical results are obtained.