Aro H T, Chao E Y
Department of Orthopedic Surgery, Johns Hopkins University, Baltimore, Maryland.
Hand Clin. 1993 Nov;9(4):531-42.
The major factors determining the mechanical milieu of a healing fracture under external fixation, and thereby the mechanism of union, are the rigidity of the selected fixation device, the fracture configuration, the accuracy of fracture reduction, and the amount of physiologic stresses dictated by functional activity and loading. Bone healing problems encountered in fractures stabilized externally merely reflect the severity of the local soft-tissue and periosteal injury and should not be attributed to the inherent features of the fixation modality. Although some surgeons have had reservations concerning the use of external fixation for fracture treatment, based mainly on concerns of pin-tract infection and fracture nonunion, much of the clinical experience and basic science research results have proven the reverse. Many of the potential benefits of external fixation, such as the change of fixation stiffness, are not yet fully appreciated. Additional research and well-organized clinical trials must be performed. Pin-tract problems can be controlled, but the surgeon using such a device must be familiar with the techniques and follow the established regimens during postoperative care. One common mistake is to assume that external fixators, especially those of the simpler unilateral configuration, are easy to use and do not require learning or mastering the surgical techniques until the time of application. Periodic examination and radiographic evaluations are also essential to adjust conditions of the fracture site. The importance of balancing the biomechanical properties and the biologic consequences of different external fixation modalities has been demonstrated. Understanding this knowledge and the techniques of application associated with external fixation is the prerequisite to successful treatment. Some of the basic biomechanical information related to external fixation and bone fracture union is still unknown. This lack should provide the impetus for surgeons, bioengineers, and medical scientists to continue collaborative basic and applied research. Furthermore, by recognizing the proper cell mediators and the physical means to stimulate these cellular elements, the bone fracture healing process may be modulated, regardless of the fixation technique. The result of such effort should provide new modalities to improve fracture management.
决定外固定治疗骨折时愈合骨折力学环境进而影响愈合机制的主要因素包括所选固定装置的刚度、骨折形态、骨折复位的准确性以及功能活动和负荷所决定的生理应力大小。外固定稳定的骨折所遇到的骨愈合问题仅仅反映了局部软组织和骨膜损伤的严重程度，不应归因于固定方式的固有特征。尽管一些外科医生对使用外固定治疗骨折有所保留，主要是担心针道感染和骨折不愈合，但许多临床经验和基础科学研究结果却证明并非如此。外固定的许多潜在益处，如固定刚度的改变，尚未得到充分认识。必须进行更多的研究和精心组织的临床试验。针道问题是可以控制的，但使用这种装置的外科医生必须熟悉相关技术并在术后护理中遵循既定方案。一个常见的错误是认为外固定器，尤其是那些较简单的单侧构型的外固定器，易于使用，在应用时不需要学习或掌握手术技术。定期检查和影像学评估对于调整骨折部位的情况也至关重要。已经证明平衡不同外固定方式的生物力学特性和生物学后果的重要性。了解这些知识以及与外固定相关的应用技术是成功治疗的前提。一些与外固定和骨折愈合相关的基本生物力学信息仍然未知。这种不足应该促使外科医生、生物工程师和医学科学家继续进行基础和应用方面的合作研究。此外，通过识别合适的细胞介质以及刺激这些细胞成分的物理手段，无论采用何种固定技术，骨折愈合过程都可能得到调节。这种努力的结果应该会提供改善骨折治疗的新方法。
