Duda G N, Heller M, Albinger J, Schulz O, Schneider E, Claes L
Department of Trauma and Reconstructive Surgery, Charité, Humboldt-University of Berlin, Germany.
J Biomech. 1998 Sep;31(9):841-6. doi: 10.1016/s0021-9290(98)00080-3.
Musculoskeletal loading influences the stresses and strains within the human femur and thereby affects the processes of bone modeling and remodeling. It is essential for implant design and simulations of bone modeling processes to identify locally high or low strain values which may lead to bone resorption and thereby affect the clinical outcome. Using a finite element model the stresses and strains of a femur with all thigh muscle and joint contact forces were calculated for four phases of a gait cycle. Reduced load sets with only a few major muscles were analyzed alternatively. In a completely balanced femur with all thigh muscles the stress and strain patterns are characterized by combined bending and torsion throughout the bone. Similar to in vivo recordings, the model with all thigh muscles showed peak surface strains below 2000 mu epsilon (45% gait cycle). Under simplified load regimes surface strains reached values close to 3000 mu epsilon. Within the proximal femur, the simplified load regimes produced differences in strain as high as 26% in comparison to those with all thigh muscles included. This difference is reduced to 5% if the adductors are added to a loading consisting of hip contact, abductors and ilio-tibial band. This study demonstrates the importance of an ensemble of muscle forces to reproduce a physiological strain distribution in the femur. Analytical attempts to simulate bone modeling, remodeling or bone density distributions should therefore rely on fully balanced external load regimes which account for the role of the various soft tissue forces.
肌肉骨骼负荷会影响人体股骨内部的应力和应变，进而影响骨骼塑形和重塑过程。识别可能导致骨吸收从而影响临床结果的局部高应变或低应变值，对于植入物设计和骨骼塑形过程的模拟至关重要。使用有限元模型，计算了一个包含所有大腿肌肉和关节接触力的股骨在步态周期四个阶段的应力和应变。另外还分析了仅包含少数主要肌肉的简化负荷集。在一个具有所有大腿肌肉的完全平衡的股骨中，应力和应变模式的特征是整个骨骼存在弯曲和扭转的组合。与体内记录相似，具有所有大腿肌肉的模型显示表面应变峰值低于2000微应变（步态周期的45%）。在简化负荷状态下，表面应变达到接近3000微应变的值。在股骨近端，与包含所有大腿肌肉的情况相比，简化负荷状态下产生的应变差异高达26%。如果在内收肌添加到由髋关节接触、外展肌和髂胫束组成的负荷中，这种差异会减小到5%。这项研究证明了一组肌肉力量对于在股骨中再现生理应变分布的重要性。因此，模拟骨骼塑形、重塑或骨密度分布的分析尝试应依赖于充分平衡的外部负荷状态，该状态考虑了各种软组织力量的作用。
