extramedullary implant

  • 文章类型: Journal Article
    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。
    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.
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  • 文章类型: Journal Article
    髋部骨折导致大量住院,造成了巨大的经济负担。大多数(>90%)的髋部骨折与侧身跌倒有关。对侧向坠落的研究通常涉及准静态或恒定位移速率的载荷,忽略了实际跌倒的物理学。了解股骨共振频率和动态载荷激发的相关模式形状也很关键。两种商业髓外植入物,股骨近端锁定钢板(PFLP)和可变角度动力髋螺钉(VA-DHS),选择对模拟的Evans-I型股骨粗隆间骨折进行临床前评估。在这项研究中,我们假设植入物的行为取决于负载类型-轴向静态和横向冲击-刚性植入结构将吸收较少的冲击能量侧向下降。使用从2D数字图像相关(DIC)研究获得的全场应变数据的实验测量结果验证了计算机模型。在3kN的峰值轴向载荷下,PFLP结构预测更大的轴向刚度(1.07kN/mm),而不是VA-DHS(0.85kN/mm),尽管前者预测近端应力屏蔽稍高。Further,具有更大的模式2频率,PFLP预测,与其他植入物相比,在抵抗侧向跌落引起的弯曲方面的性能有所提高。总的来说,PFLP植入股骨预测不良应力强度的倾向最小,提示更好的结构刚度和更高的保护股骨骨折防止跌倒的能力。
    Hip fracture accounts for a large number of hospitalizations, thereby causing substantial economic burden. Majority (> 90%) of all hip fractures are associated to sideways fall. Studies on sideways fall usually involve loading at quasi-static or at constant displacement rate, which neglects the physics of actual fall. Understanding femur resonance frequency and associated mode shapes excited by dynamic loads is also critical. Two commercial extramedullary implants, proximal femoral locking plate (PFLP) and variable angle dynamic hip screw (VA-DHS), were chosen to carry out the preclinical assessments on a simulated Evans-I type intertrochanteric fracture. In this study, we hypothesized that the behavior of the implant depends on the loading types-axial static and transverse impact-and a rigid implanted construct will absorb less impact energy for sideways fall. The in silico models were validated using experimental measurements of full-field strain data obtained from a 2D digital image correlation (DIC) study. Under peak axial load of 3 kN, PFLP construct predicted greater axial stiffness (1.07 kN/mm) as opposed to VA-DHS (0.85 kN/mm), although the former predicted slightly higher proximal stress shielding. Further, with greater mode 2 frequency, PFLP predicted improved performance in resisting bending due to sideways fall as compared to the other implant. Overall, the PFLP implanted femur predicted the least propensity to adverse stress intensities, suggesting better structural rigidity and higher capacity in protecting the fractured femur against fall.
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  • 文章类型: Journal Article
    Despite intense research and innovations in peri-operative management, a high mortality rate and frequent systemic complications in trochanteric femoral fractures persist. The aim of the present study was to identify predictive factors for mortality and cardio-respiratory complications after different treatment methods in a ten year period at a level I trauma centre.
    Retrospectively, all patients above 60 years of age with trochanteric femoral fracture between January 2000 and May 2011 were analyzed at a level I trauma centre. Demographic variables, comorbidities, and data regarding the surgical procedures, including required transfusions and post-operative complications, were evaluated, and the in-hospital mortality was recorded. The grade of osteoporosis was classified radiographically using the Singh index.
    The in-hospital mortality rate was 8.2% among 437 patients (male/female ratio = 110/327, mean age = 81 years) with extramedullary open (n = 144), intramedullary (n = 166), and extramedullary minimally invasive (n = 125) procedures. Significant influential factors on in-hospital mortality were identified with binary logistic regression analysis: an age of ≥90 years (P = 0.011), male sex (P = 0.003), a high American Society of Anesthesiologists (ASA) grade (3-5, P = 0.042), and a high osteoporosis grade (Singh index 3-1, P = 0.011). A total of 21.5% of the study population suffered cardio-respiratory complications post-operatively. The specific mortality was 28.7% (P < 0.001), which was influenced by a high ASA grade (3-5, P = 0.002) and a high transfusion rate (P = 0.004). Minimally invasive locked plating was associated with increased cardio-respiratory complications (P = 0.031).
    This study identified high patient age, distinctive comorbidities, male sex, and high osteoporosis grade as significant risk factors for increased in-hospital mortality in the treatment of trochanteric femoral fractures. Furthermore, high ASA grade and a liberal transfusion regime led to an increased incidence of cardio-respiratory complications. Patient-specific characteristics, especially osteoporosis grade and pre-existing medical conditions, may assist in the identification of high-risk patients and allow a patient-specific geriatric co-management plan.
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