Fitzpatrick D C, Foels W S, Pedersen D R, Marsh J L, Saltzman C L, Brown T D
University of Iowa, Department of Orthopaedics, Iowa City, USA.
Iowa Orthop J. 1995;15:197-203.
Aligning an articulated ankle external fixator with the ankle axis located using a mechanical axis finder has been shown to preserve normal ankle joint kinematics while the fixed hinge device is attached. However, several problems exist preventing the clinical application of this finding for fractures of the tibial plafond. We initiated a series of studies to resolve these issues. First, the accuracy of the mechanical axis finder in biological systems was quantified by comparing it to that of a computationally derived helical axis. Second, a prototype fixator design was developed in the biomechanics lab to increase the versatility of intraoperative fixator placement. Finally, a radiographic method of locating the ankle axis was developed which is based on talar morphology independent of the fractured tibia. The prototype fixator has been accurately aligned along the ankle axis in cadaveric specimens using this method. Open reduction and internal fixation (ORIF) is the accepted method of treatment for tibial plafond fractures. It holds the advantage of sufficient fracture fixation to permit early joint motion. Good results have been reported using this method, but some authors have reported complication rates up to 50%. The wide surgical approaches required, in conjunction with preexisting soft tissue injury, are thought to significantly increase the risk of soft tissue complications. In response to these problems, many investigators are beginning to utilize external fixation as an alternate treatment modality. One external fixation system which has shown particularly good results is a monolateral cross-ankle articulated fixator (Orthofix SRL., Verona, Italy) which allows motion at the ankle joint as the plafond fracture is healing (Figure 1).(ABSTRACT TRUNCATED AT 250 WORDS)
已证明，使用机械轴定位仪将关节式踝关节外固定器与所确定的踝关节轴线对齐，在连接固定铰链装置时可保持正常的踝关节运动学。然而，存在一些问题阻碍了这一发现应用于胫骨平台骨折的临床治疗。我们开展了一系列研究来解决这些问题。首先，通过将机械轴定位仪与通过计算得出的螺旋轴进行比较，量化其在生物系统中的准确性。其次，在生物力学实验室开发了一种原型固定器设计，以增加术中固定器放置的通用性。最后，开发了一种基于距骨形态且独立于骨折胫骨的踝关节轴线放射成像定位方法。使用该方法，已在尸体标本中沿踝关节轴线精确对齐原型固定器。切开复位内固定（ORIF）是治疗胫骨平台骨折公认的方法。它具有骨折固定充分、可允许早期关节活动的优点。使用该方法已报道有良好效果，但一些作者报告并发症发生率高达50%。所需的广泛手术入路，加上先前存在的软组织损伤，被认为会显著增加软组织并发症的风险。针对这些问题，许多研究人员开始将外固定作为一种替代治疗方式。一种显示出特别好效果的外固定系统是单侧跨踝关节式关节固定器（意大利维罗纳的奥托菲克斯股份公司），它可在胫骨平台骨折愈合时允许踝关节活动（图1）。（摘要截选至250词）
