Abstract：
Classically, one of the more common treatment options for rigid hammertoe correction consists of end-to-end arthrodesis stabilized by temporary Kirschner wire (K-wire) fixation maintained until osseous consolidation or complication necessitating premature removal. However, single K-wire fixation allows for axial rotation which results in loss of compression at the arthrodesis site. To counteract this, intramedullary implants were designed to provide fusion site stability in all planes negating extra-skeletal extension of the wire. Nevertheless, manual pressfit implants arguably offer less reliable positioning of the fusion site in a true end to end orientation due to variation in intramedullary stem placement compared to direct visualization with dorsal plating. Larger diameter implants create an osseous void at the bony interface reducing the potential of true bony union. Hammertoe implant failure poses a unique and challenging salvage scenario which can ultimately end in amputation. Extramedullary fixation is uniquely designed to merge both benefits of K-wires and intramedullary implants while eliminating inadequacies of each. A total of 100 patients who underwent 150 rigid hammertoe corrections with an extramedullary implant were retrospectively reviewed. The mean postoperative follow-up was 12.6 months (range 12-18 months). Overall, 94 of 100 patients (94%) achieved radiographic union, defined by 2 or more bridged cortices at the arthrodesis site without signs of hardware breakage or signs of lucency across one or more fusion sites at a mean 8.8 weeks (range 7-10 weeks). This study demonstrated excellent results in regards to postoperative arthrodesis when utilizing an extramedullary implant for hammertoe deformity correction. This device minimizes osseous deficit by extramedullary application, all while augmenting intramedullary K-wire fixation.
摘要：
经典的,刚性锤状趾矫正的一种更常见的治疗选择包括通过临时克氏针（K-wire）固定稳定的端到端关节固定术，直到骨性巩固或需要过早切除的并发症。然而,单K线固定允许轴向旋转，从而导致关节固定术部位的压缩损失。为了抵消这一点，设计了髓内植入物，以在所有平面中提供融合部位的稳定性，从而消除了金属丝的骨骼外延伸。然而，与背侧钢板的直接可视化相比，由于髓内茎放置的变化，手动pressfit植入物在真正的端到端方向上的融合部位定位可靠性较低。较大直径的植入物在骨界面处产生骨性空隙，从而降低了真正骨性结合的可能性。锤状趾植入物失败会带来独特且具有挑战性的抢救方案，最终可能会导致截肢。髓外固定术的设计独特，可以融合K线和髓内植入物的优点，同时消除各自的不足之处。回顾性分析了总共100例接受了150例髓外植入硬锤趾矫正的患者。术后随访12～18个月，平均12.6个月。总的来说,100例患者中有94例（94%）实现了影像学愈合，由关节固定术部位的2个或更多个桥接皮质定义，平均8.8周（范围7-10周），在一个或多个融合部位没有硬件断裂或通畅的迹象。这项研究证明，当使用髓外植入物进行锤趾畸形矫正时，在术后关节固定术方面取得了出色的结果。该装置通过髓外应用最大限度地减少骨缺损，同时增强髓内K线固定。
