Clinical assessment and radiographic studies used to be the only tools available for the selection of treatment modalities for thumb CMC arthritis [28,29]. Eaton and Glickel proposed a staging system for this disease that has been widely applied . Later, Bettinger and coworkers  described the trapezial tilt as an instrument to predict further progression of the disease. They found that in advanced Stages (Eaton III and IV) the trape-zial tilt was high (50° + 4°; normal: 42° + 4°). Barron and Eaton  concluded that there appears to be no indication for MRI, tomography, or ultra-sonography in the routine evaluation of basal joint disease .
Although the author believes that a radiographic classification is important for a stepwise interpretation of the progression of this entity, my experience has demonstrated instances when it is very difficult to make an accurate diagnosis of the extent of disease based solely on radiographic studies. Recent advances in arthroscopic technology have allowed complete examination of smaller joints throughout the body with minimal morbidity . Moreover, arthroscopy has already proved to be reliable for direct evaluation of the first CMC joint, as previously discussed .
In early stages of thumb basal joint arthritis, in Eaton Stage I, for instance, it is very common to find essentially normal radiographic studies despite the presence of painful limitation of the thumb. In the experience of the author and co-workers, this group of patients displays mild to moderate synovitis that could benefit from a thorough joint debridement combined with thermal shrinkage of the ligaments to enhance the stability. This, of course, assumes that they have not responded well to conservative treatment, including splinting, use of nonsteroidal antiinflammatory drugs (NSAIDs), and corticosteroid injection. This stage is typically seen in middle-aged women who tend not to be indicated for more aggressive open procedures . Arthroscopic treatment provides a particularly good option for this ubiquitous subset of patients.
Tomaino  concluded that first metacarpal extension osteotomy is a good treatment option for Eaton Stage I. This may not be necessary in the occasional patient who undergoes arthroscopy at an early time and demonstrates no focal cartilage loss. Future studies may indicate that syno-vectomy, and perhaps thermal capsulorraphy, may avoid progression of disease and the need for a mechanical intervention; however, the ar-throscopic findings that the author previously described for arthroscopic Stage II of the disease
demand a joint modification such as osteotomy, to minimize the chance of further articular degeneration. My retrospective study indicates that this approach is efficacious, with only one out of 43 thumbs developing progressive arthritis requiring further surgery.
There is no doubt that if complete articular cartilage loss is the arthroscopic scenario, then the logical further step is to perform some type of trapezium excision with interposition arthro-plasty. This can include either a partial or complete excision or replacement. Menon  described a technique demonstrating arthroscopic debride-ment of the trapezial articular surface and interposition of autogenous tendon, fascia lata, or Gore-Tex patch into the CMC joint in patients who had Stage II and III, with excellent results. Newer techniques may allow the arthroscopic insertion of Artelon (Small Bone Innovations, New York, New York), which has proven successful with open techniques and confirmed histologically . In either case, complete excision of the trapezium may not be desirable or even necessary, particularly in younger patients. This Stage III treatment needs to be further assessed by evaluating long-term clinical results.
According to the arthroscopic classification proposed, the author recommends arthroscopic synovectomy and debridement of the basal joint in patients who have Stage I arthritis. In patients who have Stage II disease, synovectomy and debridement is combined with osteotomy of the first metacarpal. In both these stages, thermal shrinkage is used to manage ligamentous laxity. Finally, for Stage III of the disease, arthroscopic interposition arthroplasty is my treatment of choice, although other factors must be considered in making this determination.
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