Use it or lose it: The relationship between two image-based biomarkers in better understanding osteoarthritis progression in the wrist.

Bone tissue is influenced by its mechanical environment and adapts in response to its mechanical load. This is supported by studies analyzing bone adaptation in the knee and hip. Changes to the bone have also been found to precede cartilage degeneration in diseases such as osteoarthritis (OA). Our objective was to demonstrate the relationship between joint contact and bone density in the wrists of healthy adults. Static CT scans with a calibration phantom were taken to obtain measures of bone mineral density (vBMD) in 3 normalized depths; 0 - 2.5, 2.5 - 5, and 5 - 7.5 mm. Participants underwent a four-dimensional CT scan (4DCT) while performing maximum wrist extension to maximum wrist flexion. 3D bone models of the distal radius, scaphoid, and lunate were made, and analyzed vBMD and joint contact area (JCA) in the radiolunate (RL) and radioscaphoid (RS) joints separately. Correlation coefficients were calculated where vBMD was the dependent variable, and kinematic JCA throughout every 10 degrees of motion were the independent variables. Statistically significant independent variables associated with vBMD were assessed using a regression model and were entered in steps; (1) significant correlations, (2) sex, and (3) age.An increase in vBMD was significantly, positively associated with an increase in JCa. Notably, in the deeper regions (5 - 7.5 mm) of the radius that is primarily composed of trabecular bone. Sex contributed to the variance in vBMD, while age did not. Subchondral bone changes are influenced by wrist position, demonstrating that the wrist serves to bear load similar to the knee and hip.