Radiographic Prevalence of Osteoarthritis of the Scaphotrapeziotrapezoid Joint in Patients With Carpometacarpal Osteoarthritis of the Thumb: A Retrospective Case Series

Background: In planning operative treatment of thumb carpometacarpal (CMC) joint osteoarthritis, surgeons should consider the presence of an arthritic scaphotrapeziotrapezoid (STT) joint. We aimed to determine the radiographic prevalence of concomitant (STT) osteoarthritis with thumb CMC osteoarthritis in patients who underwent surgical treatment at our institution. We hypothesized that the prevalence of concomitant arthritis at these 2 joints (STT and CMC) would be lower than previously reported.Methods: Between September 2005 and July 2012, a total of 417 patients were identified from our institution using the Current Procedural Terminology code for thumb CMC joint arthroplasty (25447). After applying exclusion criteria and identifying patients who underwent treatment, a total of 194 patients were included and 218 preoperative radiographs were available for review. Each radiograph was categorized according to the Eaton classification of thumb CMC osteoarthritis, with stage 4 involving the (STT) joint. Evaluation was performed by four reviewers independently.Results: A total of 47 (21.6%) patients had varying degrees of concomitant (STT) joint osteoarthritis with the thumb CMC joint osteoarthritis. Stage 4 was reported in 6.4% (14) of the radiographs.Conclusions: The radiographic prevalence of concomitant (STT) osteoarthritis with thumb CMC osteoarthritis may be lower than previously reported.Further studies that include a similarly large sample size and additional radiographic views can help evaluate the likelihood of these conditions in patients who elect to undergo surgical treatment of thumb CMC osteoarthritis.