Three-Dimensional Analysis of the Trapezium Subchondral Bone and its Association with Trapeziometacarpal Joint Osteoarthritis.

Subchondral bone properties are associated with the pathogenesis of osteoarthritis (OA), but this relationship has not been confirmed in the trapeziometacarpal joint (TMCJ). We aimed to evaluate the thickness (SBT) and density (SBD) of three-dimensional (3D) trapezium subchondral bone models derived from computed tomography (CT) images, and their relationships with early-stage TMCJ OA. We reviewed patients with a distal radius fracture who underwent conventional CT scans and such osteoporosis evaluations as bone mineral density (BMD) and bone turnover markers (BTMs). From 3D trapezium subchondral bone models, we measured SBT and SBD according to the OA stage and performed multivariate analyses to evaluate their associations with age, sex, body mass index, BMD, and BTMs. As results, a total of 156 patients (78 men and 78 age-matched women; mean age, 67 ± 10 years) were analyzed. There were 30 (19%) with grade 0, 71 (45%) with grade 1, 13 (8%) with grade 2, and 42 (27%) with grade 3 TMCJ OA. SBT was significantly lower in patients with grade 1 OA than those with grade 0 or grade 3 OA, but SBD generally increased according to the OA severity. Low SBT was associated with low BMD, and low SBD with low BMD, high osteocalcin levels, and severe OA grades. In conclusion, patients with early-stage radiographic TMCJ OA have a lower SBT at the trapezium, which may support the potential role of subchondral bone in OA pathogenesis. This study also shows that subchondral bone properties are associated with BMD and osteocalcin levels.