• Gregory I Bain, Harry D S Clitherow, Stuart Millar, François Fraysse, John J Costi, Kevin Eng, Duncan T McGuire, and Dominic Thewlis.
• Department of Orthopaedic Surgery, Flinders Hospital, Adelaide, SA; Department of Orthopaedic Surgery, and the Biomechanics & Implants Research Group, The Medical Device Research Institute, School of Computer Science, Engineering & Mathematics, Flinders University, Adelaide, SA; Department of Orthopaedics and Trauma, Royal Adelaide Hospital, Adelaide, SA; Department of Orthopaedics and Trauma, Modbury Hospital, Adelaide, SA; Department of Orthopaedics and Trauma, University of Adelaide, Adelaide, SA; Sansom Institute for Health Research & School of Health Sciences, University of South Australia, South Australia; Department of Orthopaedics and Trauma, Geelong Hospital, Geelong, Victoria, Australia; Martin Singer Hand Unit, Department of Orthopaedic Surgery, Groote Schuur Hospital and UCT Private Academic Hospital, Cape Town, South Africa.
• J Hand Surg Am. 2015 Jan 1; 40 (1): 81-9.e1.

PurposeTo assess carpal kinematics in various ranges of motion in 3 dimensions with respect to lunate morphology.MethodsEight cadaveric wrists (4 type I lunates, 4 type II lunates) were mounted into a customized platform that allowed controlled motion with 6 degrees of freedom. The wrists were moved through flexion-extension (15°-15°) and radioulnar deviation (RUD; 20°-20°). The relative motion of the radius, carpus, and third metacarpal were recorded using optical motion capture methods.ResultsClear patterns of carpal motion were identified. Significantly greater motion occurred at the radiocarpal joint during flexion-extension of type I wrist than a type II wrist. The relative contributions of the midcarpal and radiocarpal articulations to movement of the wrist differed between the radial, the central, and the ulnar columns. During wrist flexion and extension, these contributions were determined by the lunate morphology, whereas during RUD, they were determined by the direction of wrist motion. The midcarpal articulations were relatively restricted during flexion and extension of a type II wrist. However, during RUD, the midcarpal joint of the central column became the dominant articulation.ConclusionsThis study describes the effect of lunate morphology on 3-dimensional carpal kinematics during wrist flexion and extension. Despite the limited size of the motion arcs tested, the results represent an advance on the current understanding of this topic.Clinical RelevanceDifferences in carpal kinematics may explain the effect of lunate morphology on pathological changes within the carpus. Differences in carpal kinematics due to lunate morphology may have implications for the management of certain wrist conditions.Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

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