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The Diagnostic Utility of Lateral Thumb Radiographs in Detecting Thumb Carpometacarpal Arthritis
Taylor Cogsil, MD
1, Burke Gao, MD
2, Marissa Dearden, MD
1, Kartik Reddy, BA
1; Steve K Lee, MD
3(1)Hospital for Special Surgery, New York, NY, (2)Lenox Hill Hospital, New York, NY, (3)Hand and Upper Extremity Service, Hospital for Special Surgery, New York, NY
Purpose: Thumb carpometacarpal (CMC) arthritis is commonly evaluated using radiographs to guide treatment decisions. No consensus exists on optimal radiographic views or interpretation methods
. The purpose of this study was to determine whether lateral thumb radiographs demonstrate more advanced degenerative changes than Bett's anterior-posterior (AP) and oblique views in patients with thumb carpometacarpal (CMC) arthritis.
Methods: We retrospectively reviewed preoperative Bett's AP, lateral, and oblique radiographs from consecutive patients undergoing thumb CMC arthroplasty (June 2023-March 2025). Two reviewers independently evaluated radiographs using the Osteoarthritis Research Society International atlas, grading joint space narrowing (JSN) and osteophyte severity (both on 0-3 scales) and recording presence/absence of erosions, subchondral sclerosis, and cysts. Each reviewer scored radiographs twice with minimum 1-week interval. Statistical analysis employed non-parametric tests for ordinal severity scores and matched-pair analysis for binary outcomes. Cohen's kappa assessed inter- and intra-rater reliability.
Results: Twenty-five patients (38 radiograph sets) were included (mean age 61 years; 52% female). Lateral views showed significantly higher JSN scores (2.22) versus AP (1.41, p<0.0001) and oblique (1.55, p<0.0001) views. Erosions were detected in 96% of lateral views versus 68% of AP (p<0.001) and 83% of oblique (p=0.022) views. Cysts were present in 75% of lateral views versus 50% of AP (p<0.001) and 62% of oblique (p=0.039) views. Intra-rater reliability for erosion detection was superior on lateral views (?=1.00) compared with AP (?=0.39, p<0.001) and oblique (?=0.21, p=0.001) views.
Conclusions: Lateral thumb radiographs demonstrate more advanced degenerative changes, particularly erosions and joint space narrowing, compared with standard AP and oblique views in thumb CMC arthritis evaluation.
Type of study/level of evidence: Case Series, IV
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