Carpal Kinematics in Madelung Deformity
Abbas Peymani, MD MS1, Johannes G.G. Dobbe, PhD2, Geert J. Streekstra, PhD2, H. Relton McCarroll, MD3 and Simon D. Strackee, MD PhD2, (1)Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands, (2)Amsterdam Medical Center, University of Amsterdam, Amsterdam, Netherlands, (3)Department of Orthopaedic Surgery, Shriners Hospital for Children Northern California, Sacramento, CA
The decreased wrist mobility in Madelung deformity has been quantified extensively, but the mechanisms underlying these effects are not understood. We hypothesize that the previously identified abnormal radiolunate and radiotriquetral ligaments lead to decreased movement of the lunate and triquetrum bones.
Materials & Methods
We evaluated carpal bone kinematics of 9 Madelung deformity wrists (5 patients) and 18 healthy wrists (9 volunteers), using a novel four-dimensional (4D) radiographic scanning technique. This method combines static CT scans with dynamic scans acquired during motion to quantify carpal bone kinematics in-vivo. We developed software programs to calculate and visualize movement (total translation and total rotation) of wrist bones during flexion-extension and radio-ulnar deviation. To compare carpal bone kinematics we developed 12 mixed effects models, one for each combination of: 3 proximal carpal bones (scaphoid, lunate, and triquetrum), 2 distinct motions (flexion-extension and radio-ulnar deviation), and 2 outcomes of interest (total translation and total rotation).
During flexion-extension motion a significantly decreased rotation was seen in both the lunate bone (difference in degrees, -4.6; 95% CI -7.1 to -2.2; P=0.001) and the triquetrum bone (difference in degrees, -4.8; 95% CI -6.7 to -3.0; P<0.001) for Madelung deformity wrists. Carpal kinematics during radio-ulnar deviation showed significant decreased in lunate bone translation (difference in mm, -0.7; 95% CI -1.0 to -0.4; P<0.001), triquetrum bone translation (difference in mm, -0.6; 95% CI -0.9 to -0.3; P=0.001), and triquetrum bone rotation (difference in degrees, -1.9; 95% CI -3.7 to -0.1; P=0.049). There were no significant differences found for scaphoid bone translation and rotation during flexion-extension motion or radio-ulnar deviation.
This is the first study to evaluate carpal bone kinematics in Madelung deformity. In comparison to wrists of healthy participants, wrists of Madelung deformity patients show decreased movement of lunate and triquetrum bones. Previously identified abnormal radiolunate and radiotriquetral ligaments could explain the decreased wrist mobility.
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