Radiographic Progression of Thumb CMC Osteoarthritis: A Systematic Review.

Purpose: Thumb carpometacarpal (CMC) osteoarthritis (OA) is a prevalent disease that causes pain and disability. Determining the progression of CMC OA is problematic given the lack of consensus for classifications and scoring systems. We performed a systematic review to (1) determine which imaging modalities or scoring systems are used to evaluate CMC OA progression, and (2) describe the progression of CMC OA through available metrics. Methods: This review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. An English language literature search was performed in July 2019 and included studies evaluating CMC OA progression with an imaging modality or radiographic scoring system, with a minimum 1-year follow-up. Studies were analyzed with respect to their methodology, scoring systems, and relevant findings. Results: The initial search yielded 4,097 articles, 10 of which met inclusion criteria. Study size varied from 32 to 289 subjects; many subjects were included in multiple cohorts. Eight studies used radiography whereas 2 used scintigraphy. Estimates of progression varied from 20% to 70% (with large variation in follow-up time); the magnitude of progression varied from 3% to 48% (joint space narrowing) and from 0.6 to 1 points (Kellgren-Lawrence scale). The percentage of subjects who progressed and the progression degree varied widely and depended on follow-up length and the scoring system used. Conclusions: A paucity of literature exists to measure CMC OA progression; there is a lack of uniformly accepted imaging modality, scoring system, or follow-up interval. This absence provides the opportunity to determine consensus techniques and metrics to assess the natural history of thumb CMC OA. Type of study/level of evidence: Diagnostic III.