Department of Hand and Wrist Surgery, Orthopaedic and Trauma Department, Hospital Universitari Son Espases and IBACMA Institute, Palma de Mallorca, Spain, Camí de la Vileta, 30, 07011 Palma, Mallorca, Illes Balears, Spain.
Consultant in Hand and Upper Extremity Surgery, Kaplan Institute, Barcelona, Passeig de la Bonanova, 9, 08022 Barcelona, Spain.
Clin Biomech (Bristol). 2020 Jul;77:105046. doi: 10.1016/j.clinbiomech.2020.105046. Epub 2020 May 11.
Most laboratory studies investigating scapholunate dissociations are based on normal cadaver arms with serially sectioned ligaments. It is assumed that the kinetic behavior of a ligament-sectioned wrist is similar to a scapholunate dissociation. We tested five cadaver wrists with real injuries. The goal of this research was to evaluate the biomechanical behavior of scapholunate advanced collapse wrists compared to an experimental group with simulated injuries.
Using a magnetic 6-degree of freedom motion tracking device, changes in scaphoid alignment induced by isometric loading 5 wrist motor tendons in two groups of specimens were monitored. Twelve fresh cadaver wrists in which scapholunate injury was simulated by sectioning the scapholunate ligament were compared to 5 arms with chronic scapholunate dissociation.
The behavior of the scaphoid is the same in both groups, but the magnitude of displacement is greater in chronic scapholunate dissociation wrists, although not statistically significant. The extensor carpi ulnaris is the only muscle that provokes scaphoid pronation; all other muscles induce its supination.
Different factors may play a role in the amount of scaphoid rotation observed in wrists with chronic scapholunate dissociation. Ligament sectioning alone in the experimental setup can only partially replicate the behavior of real scapholunate dissociations. The extensor carpi ulnaris has a major role in destabilizing scapholunate advanced collapse wrists; therefore, isometric contraction of this muscle should be avoided in the conservative treatment. The experimental setup designed is useful to evaluate the biomechanical behavior of the carpus under traction load.
大多数研究舟月骨分离的实验室研究都是基于连续切片韧带的正常尸体手臂进行的。据推测，切断韧带的手腕的动力学行为与舟月骨分离相似。我们测试了五个带有真实损伤的尸体手腕。本研究的目的是评估与模拟损伤的实验组相比，舟月骨晚期塌陷手腕的生物力学行为。
使用磁性 6 自由度运动跟踪装置，监测两组标本在等距加载 5 个腕部运动肌腱时舟骨对线的变化。将 12 个新鲜尸体手腕中通过切断舟月骨韧带模拟舟月骨损伤的标本与 5 个慢性舟月骨分离的手臂进行比较。
两组标本舟骨的行为相同，但慢性舟月骨分离手腕的位移幅度较大，但无统计学意义。尺侧腕伸肌是唯一引起舟骨旋前的肌肉；所有其他肌肉都使其旋后。
慢性舟月骨分离手腕中观察到的舟骨旋转量可能有不同的因素起作用。实验装置中仅切断韧带只能部分复制真实舟月骨分离的行为。尺侧腕伸肌在不稳定舟月骨晚期塌陷手腕中起主要作用；因此，在保守治疗中应避免该肌肉等长收缩。设计的实验装置可用于评估牵引负荷下腕骨的生物力学行为。
