Pain, function, and radiographic disease in trapeziometacarpal osteoarthritis

Introduction: Trapeziometacarpal joint osteoarthritis (OA) produces significant functional impairment due to pain and loss of strength in both power and precision grips, but few studies have related radiographic scores to functional and pain-based measures. Purpose: To investigate the association between markers of radiographic disease and outcomes for symptomatic and functional disease. Study Design: This study in an exploratory analysis of baseline data from the first 100 participants in a clinical trial evaluating the efficacy of combined conservative therapies for base of thumb OA (COMBO). Methods: Functional Index for Hand Osteoarthritis (FIHOA) scores and Visual Analogue Scale (VAS) scores for pain were recorded for the index hand. Bilateral isometric grip and tip-pinch strength measurements were taken, as well as posteroanterior and Eaton stress-view hand radiographs. Generalized estimating equations (GEEs), univariate, and multivariate analyses were used according to whether the data were bilateral or unilateral. Results: A total of 79 females and 21 males were included, with a median Kellgren-Lawrence (KL) grade of 3 in the index hand. Higher KL and Eaton grades were associated with lower grip strength in the GEE analysis (B-coefficients of -1.25 and -1.16, and P-values of .002 and .010, respectively). Higher KL grade was also associated with poorer function and higher pain levels in the multivariable analysis (B-coefficients of 1.029 and 3.681, and P-values of .021 and .047, respectively). Lower radial subluxation ratios were associated with lower grip strength in the GEE analysis, and higher pain scores in the multivariable analysis (B-coefficients of 2.06 and -42.1, and P-values of .006 and .031, respectively). Greater pain scores were also associated with poorer function (B-coefficient 0.082, P-value .001). Conclusion: More advanced radiographic trapeziometacarpal OA severity is associated with lower grip strength and poorer self-reported functional outcomes. Lower subluxation ratios were associated with higher pain scores and lower grip strength.