Leventhal Evan L, Moore Douglas C, Akelman Edward, Wolfe Scott W, Crisco Joseph J
Bioengineering Laboratory, Department of Orthopaedics, The Warren Alpert Medical School of Brown University and Rhode Island Hospital, Providence, RI 02903, USA.
J Hand Surg Am. 2010 Feb;35(2):237-44. doi: 10.1016/j.jhsa.2009.11.013.
Wrist distraction is a common treatment maneuver used clinically for the reduction of distal radial fractures and midcarpal dislocations. Wrist distraction is also required during wrist arthroscopy to access the radiocarpal joint and has been used as a test for scapholunate ligament injury. However, the effect of a distraction load on the normal wrist has not been well studied. The purpose of this study was to measure the three-dimensional conformational changes of the carpal bones in the normal wrist as a result of a static distractive load.
Using computed tomography, the dominant wrists of 14 healthy volunteers were scanned at rest and during application of 98 N of distraction. Load was applied using finger traps, and volunteers were encouraged to relax their forearm muscles and to allow distraction of the wrist. The motions of the bones in the wrist were tracked between the unloaded and loaded trial using markerless bone registration. The average displacement vector of each bone relative to the radius was calculated, as were the interbone distances for 20 bone-bone interactions. Joint separation was estimated at the radiocarpal, midcarpal, and carpometacarpal joints in the direction of loading using the radius, lunate, capitate, and third metacarpal.
With loading, the distance between the radius and third metacarpal increased an average of 3.3 mm +/- 3.1 in the direction of loading. This separation was primarily in the axial direction at the radiocarpal (1.0 mm +/- 1.0) and midcarpal (2.0 mm +/- 1.7) joints. There were minimal changes in the transverse direction within the distal row, although the proximal row narrowed by 0.98 mm +/- 0.7. Distraction between the radius and scaphoid (2.5 mm +/- 2.2) was 2.4 times greater than that between the radius and lunate (1.0 mm +/- 1.0).
Carpal distraction has a significant (p < .01) effect on the conformation of the carpus, especially at the radiocarpal and midcarpal joints. In the normal wrist, external traction causes twice as much distraction at the lunocapitate joint than at the radiolunate joint.
腕关节牵引是临床上用于复位桡骨远端骨折和腕中关节脱位的常见治疗手法。腕关节镜检查时也需要进行腕关节牵引以进入桡腕关节，并且已被用作舟月韧带损伤的一项检查。然而，牵引负荷对正常腕关节的影响尚未得到充分研究。本研究的目的是测量正常腕关节在静态牵引负荷作用下腕骨的三维构象变化。
利用计算机断层扫描，对14名健康志愿者的优势腕在休息时以及施加98 N牵引时进行扫描。使用指套施加负荷，并鼓励志愿者放松前臂肌肉以使腕关节被牵引。在未加载和加载试验之间，使用无标记骨配准追踪腕骨的运动。计算每块骨头相对于桡骨的平均位移向量，以及20种骨 - 骨相互作用的骨间距离。使用桡骨、月骨、头状骨和第三掌骨，在加载方向上估计桡腕、腕中及腕掌关节的关节间隙。
加载时，桡骨与第三掌骨之间的距离在加载方向上平均增加3.3 mm±3.1。这种间隙主要在桡腕关节（1.0 mm±1.0）和腕中关节（2.0 mm±1.7）处沿轴向。远侧列在横向上变化极小，尽管近侧列变窄了0.98 mm±0.7。桡骨与舟骨之间的牵引（2.5 mm±2.2）比桡骨与月骨之间的牵引（1.0 mm±1.0）大2.4倍。
腕关节牵引对腕骨的构象有显著影响（p <.01），尤其是在桡腕关节和腕中关节。在正常腕关节中，外部牵引在月头关节处引起的牵引是桡月关节处的两倍。
