Carpal Kinematics in Madelung Deformity.

Abstract

Various skeletal and soft tissue abnormalities have been identified in Madelung deformity and have been hypothesized to play a causal role in its progressive symptomatology; however, our pathological understanding of these changes remains limited. In this study, we biomechanically assessed the Madelung deformity wrist, using 4-dimensional computed tomography imaging. Nine Madelung deformity wrists (5 patients; age, 24 ± 5 y) and 18 healthy wrists (9 volunteers; age, 28 ± 3 y) underwent 4-dimensional imaging during flexion-extension motion and radioulnar deviation. Carpal kinematics and radiocarpal joint parameters were quantified and compared. In Madelung deformity wrists, significantly decreased rotation was seen in the lunate (-4.6°) and the triquetrum (-4.8°) during flexion-extension motion. During radioulnar deviation, significant decreases were visible in lunate bone translation (-0.7 mm), triquetrum bone translation (-0.6 mm), and triquetrum bone rotation (-1.9°). Patients had significantly decreased articulating surface areas of the scaphoid (1.4 ± 0.2 cm² versus 1.6 ± 0.2 cm²) and lunate (1.2 ± 0.4 cm² versus 1.5 ± 0.3 cm²) fossa, and significantly increased radioscaphoid (1.3 ± 0.1 mm versus 1.2 ± 0.1 mm) and radiolunate (1.6 ± 0.2 mm versus 1.3 ± 0.3 mm) joint space thicknesses. There is a decreased mobility of the lunate and triquetrum bones in Madelung deformity. Four-dimensional imaging could be used in future studies that investigate the effect of surgical ligament release on carpal kinematics and subsequent wrist mobility.