Abstract:
Assessment of scaphoid fracture union on computed tomography scans is not currently standardized. We investigated the extent of scaphoid waist fracture union required to withstand physiological loads in a finite element model, based on a high-resolution CT scan of a cadaveric forearm. For simulations, the scaphoid waist was partially fused at the radial and ulnar sides. A physiological load of 100 N was transmitted to the scaphoid and the minimal amount of union to maintain biomechanical stability was recorded. The orientation of the fracture plane was varied to analyse the effect on biomechanical stability. The results indicate that the scaphoid is more prone to re-fracture when healing occurs on the ulnar side, where at least 60% union is required. Union occurring from the radial side can withstand loads with as little as 25% union. In fractures more parallel to the radial axis, the scaphoid seems less resistant on the radial side, as at least 50% union is required. A quantitative CT scan analysis with the proposed cut-off values and a consistently applied clinical examination will guide the clinician as to whether mid-waist scaphoid fractures can be considered as truly united.
摘要:
计算机断层扫描对舟骨骨折结合的评估目前尚未标准化。我们在有限元模型中研究了承受生理载荷所需的舟骨腰部骨折结合的程度,基于尸体前臂的高分辨率CT扫描。对于模拟,舟骨腰部在桡侧和尺侧部分融合。将100N的生理负荷传递到舟骨,并记录了维持生物力学稳定性的最小结合量。改变骨折平面的方向以分析对生物力学稳定性的影响。结果表明,尺侧发生愈合时,舟骨更容易再次骨折,至少需要60%的工会。从径向侧发生的接头可以承受少至25%接头的载荷。在更平行于径向轴的裂缝中,舟骨在桡侧似乎阻力较小,因为至少需要50%的工会。具有建议的截止值的定量CT扫描分析和一致应用的临床检查将指导临床医生是否可以将中腰舟骨骨折视为真正的团结。