title: Dart-throwing motion in patients with scapholunate instability: a dynamic four-dimensional computed tomography study.
abstract: When the normal wrist rotates along the 'dart-throwing' plane, the proximal row remains still, with most motion occurring at the midcarpal joint. Whether this behaviour is maintained when the scapholunate ligaments are torn is not known. If this is the case, patients having a scapholunate ligament repair could benefit from early dart-throwing exercises without the risk of pulling the sutures apart. Using dynamic computer tomography, we analysed the carpal behaviour of six normal wrists and six wrists with scapholunate instability during dart-throwing motion. In the normal wrists, the scaphoid and lunate did not flex or extend, but translated along the frontal plane an average 5.9 and 5.6 mm, respectively. When the scapholunate ligaments were torn, the scaphoid shifted towards the radial styloid considerably more than the lunate (12.8 mm versus 4.8 mm; p = 0.005), inducing a scapholunate gap. Based on these findings, we cannot recommend dart-throwing exercises after scapholunate ligament repair, unless the joint is stabilized with wires or screws.
authors.affiliation: 1Institut Kaplan, Hand and Upper Extremity Surgery, Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Garcia-Elias
authors.forename: X
authors.initials: X
authors.lastname: Alomar Serrallach
authors.forename: J
authors.initials: J
authors.lastname: Monill Serra
mesh_terms: D001696:Biomechanical Phenomena; D002348:Carpal Bones / Q000000981:diagnostic imaging*; D050824:Carpal Joints / Q000000981:diagnostic imaging* / Q000293:injuries*; D016022:Case-Control Studies; D056973:Four-Dimensional Computed Tomography; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000534:rehabilitation* / Q000601:surgery; D008023:Ligaments, Articular / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery; D061330:Multidetector Computed Tomography; D016059:Range of Motion, Articular / Q000502:physiology*; D014954:Wrist Injuries / Q000000981:diagnostic imaging / Q000534:rehabilitation / Q000601:surgery
keywords: Carpal kinematics; computed tomography; dart-throwing motion; scapholunate ligaments; wrist instability