下肢骨折畸形愈合对膝关节影响的生物力学研究和有限元分析

Fractures of the femur and tibia are common injuries in clinic. Residual rotational deformity, angular deformity with or without malalignment are common complications, which may lead to osteoarthritis, subsequently impairing the long-term functional recovery. For some patients with severe symptoms, secondary or salvage surgery will be required. In the current study, various deformity of tibial fracuture and femoral fracture will be produced. Radiographic measurement and biomechanical test will be employed to explore the correlation beteween the ratational deformity and malalignment of tibia and femur, and to study the effect of various rotational and malalignment deformity of tibia and femur on the weight-bearing area and stress distribution of knee joint. In this study, three dimensional finite element model of lower extremity fracture with various rotational deformity and malalignment will be established. This model will be employed to explore the correlation beteween the ratational or angular deformity and malalignment of the tibia and femur, and to study the effect of various rotational and angular deformity of tibia and femur on the weight-bearing area and stress distribution of knee joint. The scientificity nand reliability of the study will be analyzed by comparing the biomechanical test and the finite element analysis. Based upong the systematic study, the quantitative relationship between bearing-area and stress distribution of knee joint and various residual deformity and malalignment will be analyzed, which will provide a scientific basis for assessing the quality of reduction of lower extremity fractures.

股骨骨折和胫骨骨折是临床常见损伤，骨折愈合后残留旋转畸形、成角畸形伴或不伴下肢力线不良是其常见并发症，可能造成骨性关节炎，影响患者远期疗效。部分患者症状严重，需行二次手术治疗。本研究通过制作下肢骨折不同程度畸形愈合模型，利用影像学研究和生物力学研究手段，考量不同程度股骨或胫骨旋转与力线偏移的关系，考量股骨或胫骨不同程度旋转畸形导致膝关节负重面积和应力分布的改变。本研究将建立残留不同程度畸形和力线不良的下肢骨折三维有限元模型，考量不同程度畸形与力线偏移的关系，考量股骨或胫骨旋转畸形、成角畸形导致膝关节负重面积和应力分布的改变。通过将生物力学实验和有限元分析对比来验证研究结果的科学性、可靠性，系统分析上述数据，综合考量下肢骨折愈合后不同程度畸形和力线不良与膝关节负重面积和应力改变的量化关系，为临床上评估下肢胫骨骨折复位质量提供科学依据。

股骨或胫骨骨折后常残留不同程度畸形或力线不良，影响下肢功能恢复。本研究通过生物力学研究、有限元分析和临床试验，评估下肢骨折复位质量及残留畸形对膝关节负重及应力分布变化的影响。研究发现：1.对于股骨和胫骨不同程度畸形愈合，膝关节内侧应力较外侧应力大；2.膝关节外侧应力随着股骨（或胫骨）外翻畸形角度的增加而呈现递增趋势，而随着内翻畸形角度的增加而降低；3.膝关节内侧应力随着股骨（或胫骨）外翻畸形角度的增加而呈现递减趋势，随着内翻畸形加重而升高；4.膝关节内侧应力随着股骨（或胫骨）外旋畸形加重出现递减趋势，而内旋畸形加重则出现递增趋势；5.膝关节外侧应力随着股骨内旋畸形角度的增加而递减；6.膝关节外侧应力与股骨外旋畸形、胫骨外旋畸形或胫骨内旋畸形之间未见相关性。本研究揭示了股骨/胫骨畸形愈合对膝关节生物力学特性的影响；临床治疗下肢骨折时，应提高复位质量，避免各种畸形，提高骨折治疗效果。