Value of trapeziometacarpal joint imaging in the surgical management of basal thumb arthritis

Background: Management of trapeziometacarpal (TMC) joint degeneration requires precise imaging to assess the extent of osteoarthritis and guide clinical decision-making. Despite its importance, obtaining high-quality radiographs of the thumb base is technically demanding and often complicated by inconsistent positioning or a lack of specialized training among radiology staff.

Objective: This article describes the clinical utility of static and dynamic radiographic views, advanced imaging modalities such as cone-beam computed tomography (CBCT), and diagnostic arthroscopy in evaluating TMC joint morphology, dysplasia, and degenerative changes.

Key Points: Radiological assessment relies on standardized classifications, including the Eaton, Dell, and Allieu systems, which categorize joint space narrowing, subluxation, and peritrapezial involvement. Essential projections include Kapandji’s frontal and lateral views, Robert’s anteroposterior view, and stress views to evaluate joint stability. Specialized views, such as Gedda’s (Bett’s) and dynamic radial/ulnar deviation images, are necessary to visualize the scaphotrapeziotrapezoid (STT) joint. Quantitative measures of trapezial dysplasia include the trapezial tilt (Dévers angle) and trapezial inclination. While CBCT provides high-resolution cartilage evaluation with lower radiation doses, arthroscopy remains the most definitive method for assessing the topography of chondral damage. Notably, radiographic severity does not always correlate with clinical pain levels.

Conclusion: Accurate diagnosis of basal thumb arthritis necessitates a comprehensive radiographic protocol and specialized technician training. Integrating dynamic views and advanced imaging ensures a precise anatomical assessment, though clinical symptoms must remain the primary indication for surgical intervention.