三种股骨近端髓内钉固定股骨转子间骨折的有限元分析

[目的]通过三维有限元法对PFNA、PFNA -Ⅱ和InterTan3种股骨近端髓内固定系统固定股骨转子间骨折的生物力学稳定性进行对比,为临床应用提供理论依据.[方法]建立Tronzo-Evans Ⅰ、Ⅳ、Ⅴ型股骨转子间骨折内固定三维有限元模型,研究不同内固定的yon Mise应力分布、股骨的von Mises应力分布并比较股骨及内固定模型内外侧应力峰值,分析骨折固定后生物力学稳定性.[结果]股骨近端应力分布与骨折类型有关;Tronzo-Evans Ⅰ型骨折3种内固定的固定效果无差异;Tronzo-EvansⅣ和V型骨折使用InterTan固定yon Mises应力分布均匀,生物力学稳定型较其他两者更具优势;内固定应力集中区域位于主钉与头钉接触点下方,其中InterTan yon Mises应力分布最大效应值最大,其次为PFNA-Ⅱ、PFNA; PFNA近端广泛呈现应力集中区域现象.[结论]InterTan治疗股骨转子间骨折时股骨端应力分布合理,尤其对Tronzo-EvansV型骨折较PFNA及PFNA-Ⅱ更具优势;PFNA固定模型应力分布不均,可能为与亚洲人髓腔不匹配所致.     

A carbon fiber-reinforced polyetheretherketone intramedullary nail improves fracture site visibility on postoperative radiographic images

IntroductionTo evaluate the advantages of a carbon fiber-reinforced polyetheretherketone (CFR/PEEK) intramedullary nail on the diagnosis of fracture healing because of its radiolucency, we retrospectively reviewed radiographs and computed tomography (CT) images of trochanteric femoral fractures that underwent internal fixation with the CFR/PEEK intramedullary nail or a traditional metallic intramedullary nail.MethodsRadiographs and CT images from 20 patients with intertrochanteric femoral fractures treated with a CFR/PEEK intramedullary nail and 20 similar patients treated with a metallic intramedullary nail were reviewed. After division of the intertrochanteric region into three zones on anteroposterior and lateral views of the radiographs, the visibilities of the fracture site, fracture line, and bone formation were evaluated in each zone. A three-grade assessment for existence of scattering and effect of scattering on diagnosis of the surrounding bone was performed on three axial slices of the CT images.ResultsIn the CFR/PEEK group, the fracture site was visible in all zones for all cases except for the posterior zone on the lateral view in one case. In the cranial and middle zones on anteroposterior views and the middle zone on lateral views of the radiographs, the visible fracture site rates in the CFR/PEEK group were significantly higher than those in the metal group. The grades for existence of scattering and effect of scattering on diagnosis of surrounding bone on the CT images were significantly lower in the CFR/PEEK group compared with the metal group.ConclusionSuperior fracture site visibility on radiographs was demonstrated in cases treated with the CFR/PEEK intramedullary nail compared with cases treated with the traditional metallic intramedullary nail, thereby confirming the advantages of the CFR/PEEK intramedullary nail for evaluation of fracture reduction and bone formation. The CFR/PEEK nail evoked little scattering on CT images, leading to higher diagnostic values for the peri-prosthetic cancellous and cortical bone compared with the metallic nail.     

Titanium Alloy Gamma Nail versus Biodegradable Magnesium Alloy Bionic Gamma Nail for Treating Intertrochanteric Fractures: A Finite Element Analysis

ObjectiveTo using finite element analysis to investigate the effects of the traditional titanium alloy Gamma nail and a biodegradable magnesium alloy bionic Gamma nail for treating intertrochanteric fractures.MethodsComputed tomography images of an adult male volunteer of appropriate age and in good physical condition were used to establish a three‐dimensional model of the proximal femur. Then, a model of a type 31A1 intertrochanteric fracture of the proximal femur was established, and the traditional titanium alloy Gamma nails and biodegradable magnesium alloy bionic Gamma nails were used for fixation, respectively. The von Mises stress, the maximum principal stress, and the minimum principal stress were calculated to evaluate the effect of bone ingrowth on stress distribution of the proximal femur after fixation.ResultsIn the intact model, the maximum stress was 5.8 MPa, the minimum stress was −11.7 MPa, and the von Mises stress was 11.4 MPa. The maximum principal stress distribution of the cancellous bone in the intact model appears in a position consistent with the growth direction of the principal and secondary tensile zones. After traditional Gamma nail healing, the maximum stress was 32 MPa, the minimum stress was −23.5 MPa, and the von Mises stress was 31.3 MPa. The stress concentration was quite obvious compared with the intact model. It was assumed that the nail would biodegrade completely within 12 months postoperatively. The maximum stress was 18.7 MPa, the minimum stress was −12.6 MPa, and the von Mises stress was 14.0 MPa. For the minimum principal stress, the region of minimum stress value less than −10 MPa was significantly improved compared with the traditional titanium alloy Gamma nail models. Meanwhile, the stress distribution of the bionic Gamma nail model in the proximal femur was closer to that of the intact bone, which significantly reduced the stress concentration of the implant.ConclusionThe biodegradable magnesium alloy bionic Gamma nail implant can improve the stress distribution of fractured bone close to that of intact bone while reducing the risk of postoperative complications associated with traditional internal fixation techniques, and it has promising clinical value in the future.     

股骨近端髓内钉治疗股骨转子间骨折

目的探讨股骨近端髓内钉治疗股骨转子间骨折的疗效。方法回顾分析2001年2月～2004年2月应用股骨近端髓内钉治疗股骨转子间骨折30例。结果本组病人28例得到随访,随访时间平均8个月,骨折全部愈合,无髋内翻并发症。结论股骨近端髓内针具有抗旋转稳定性能好,手术操作简单,创伤小,是治疗转子间骨折较理想的一种方法。     

The lateral femoral wall thickness on the risk of post-operative lateral wall fracture in intertrochanteric fracture after DHS fixation: A finite element analysis

BackgroundPatients with a lateral femoral wall (LFW) fracture were reported to have high rates of re-operation and complication. Although the LFW thickness was a reliable predictor of post-operative or intra-operative LFW fracture, there was a paucity of literature evaluating the critical stress distributions on the femur and screws of intertrochanteric fractures treated with dynamic hip screw (DHS). This study aimed to investigate the biomechanical performance of intertrochanteric fractures with different LFW thickness treated with DHS device.MethodsA three-dimensional model of the proximal femur was established by computed tomography images. The intertrochanteric fracture model with three different LFW thickness (10 mm, 20.5 mm and 30 mm, respectively) was created, which was fixed by DHS. The von Mises stress on the proximal femur, lateral femoral wall, DHS and the total displacement of the device components were evaluated and compared for three different LFW thickness model.ResultsThe maximum von Mises stress in the proximal fragment of the 10 and 20.5 mm model increased by 80.56% and 57.97% when compared with the 30 mm model. The peek von Mises stress around the blade entry point of the 10 mm and 20.5 mm model increased by 89.26% and 66.39% when compared with the 30 mm model. The peek von Mises in the DHS located near the junction of the barrel and side plate of each model and the 30 mm model had the smallest von Mises stress compared with the other two models. Furthermore, the maximum displacement in the 30 mm model was much smaller than that in the10mm model and 20 mm model.ConclusionsThe intertrochanteric fracture with a thinner LFW tended to have a higher risk of LFW fracture stabilized by a DHS device. Thus, the intertrochanteric fractures with a thinner LFW should not be treated by DHS alone and the intramedullary nail or an addition of trochanteric stabilization plate(TSP) was recommended.     

Finite element study of intramedullary osteosynthesis in the treatment of trochanteric fractures of the hip: Gamma and PFN

The ongoing debate surrounding the surgical treatment of trochanteric hip fractures, particularly unstable fractures, has led to continuous changes in the design of well-established implants and to the development of new ones. The goal of this paper was to use a finite element simulation to compare the biomechanical behaviour of two intramedullary implants most often used at the University Hospital of Zaragoza: the standard Gamma nail (Howmedica) and the proximal femoral nail (PFN, Stratec). The main focus was on the displacements of the fracture focus and the stress distributions along the femur and the implant. Both nails produced an important redistribution of stress in the bone tissue, but the redistribution of peak stress was higher for the Gamma nail. On the other hand, with PFN there were smaller displacements at the fracture site. Finally, under the same workload, the Gamma nail supported higher stresses than the PFN.     

三种髓内钉治疗股骨转子间骨折的临床研究

目的 观察Gamma钉、股骨近端髓内钉(PFN)和防旋股骨近端髓内钉(PFNA)三种髓内钉治疗股骨转子间骨折的疗效. 方法回顾性分析2004年1月至2007年6月手术治疗的126例股骨转子间骨折患者的临床资料,其中Gamma钉治疗46例,PFN治疗29例,PFNA治疗51例.比较三组患者的手术时间、术中失血量、并发症发生情况、骨折愈合情况及术后髋关节Harris评分.结果 126例患者中共有91例获得到随访,时间11～39个月(平均21.6个月),三组患者在并发症发生情况、骨折愈合时间、关节功能评分上差异均无统计学意义(P>0.05),但PFNA组的手术时间、术中出血量少于其他两组(P<0.05),而PFN组与Gamma钉组之间差异无统计学意义(P>0.05). 结论Gamma钉、PFN和PFNA三种髓内钉均适合用于治疗股骨转子间骨折,其中PFNA操作相对简单,可缩短手术时间,减少术中出血.     

The effect of locked distal screws in retrograde nailing of osteoporotic distal femur fractures: a laboratory study using cadaver femurs

OBJECTIVES: To examine the effects of locked distal screws in retrograde nails used in unstable osteopenic distal femur fractures. DESIGN: Biomechanical testing of paired human cadaveric femurs. INTERVENTION: Seven matched pairs of embalmed, moderately osteopenic cadaver femurs were instrumented with 12-mm intramedullary nails in a statically locked, retrograde fashion. One femur of each pair had locked distal screws and the other femur had unlocked distal screws. A 2.5-cm gap of bone was cut nine centimeters from the distal condyles to simulate an unstable fracture. The locked distal screw nails were compared to unlocked distal screw nails for collapse of the fracture gap, medial-lateral and anterior-posterior translation of the nail within the fracture site, and fracture angulation. The femurs were axially loaded, cycled, and then loaded to failure. MAIN OUTCOME MEASURES: Motion at the fracture site with axial cyclic loading and site of failure when loaded to failure. RESULTS: After cycling, both locked distal screw and unlocked distal screw nails demonstrated several millimeters medial and anterior translation within the fracture site and approximately 1 mm collapse of the fracture gap. Although no statistically significant differences were found, the locked distal screw nails had less anterior and medial translation, angulation, and collapse of the fracture gap after cycling. Loads to failure were similar for both locked distal screw and unlocked distal screw nails. It was noted that proximal femur failure occurred at the level of the proximal screw hole in the nail at the subtrochanteric level in 7 (4 locked distal screws and 3 unlocked distal screw groups) of the 14 samples. Four other samples failed through the intertrochanteric region (2 locked distal screw and 2 unlocked distal screw groups) and the remainder within the distal fragment by fracture of the femur along the medial cortex. CONCLUSIONS: Although most differences in fixation stability were not significant, the locked distal screw nails exhibited less fracture collapse and anterior and medial translation of the nail at the fracture site than the unlocked distal screw nails. The degree of varus angulation after cyclic loading was also less for the locked distal screw nails. The length of the nail chosen should avoid having proximal locking screws distal to the lesser trochanter, thus averting proximal femur stress risers and fractures.     

Variability of human femoral geometry and its implications on nail design

ObjectivesThe objectives of this study are to present a new method of quantifying variability in human femoral geometry and to use this data to optimize intramedullary nail geometry for a better fit within the femoral canal.MethodsComputed tomography (CT) scans of forty intact adult human femora were divided according to race, sex, and age, and were reconstructed digitally into three-dimensional solid models. Geometric features were then measured and compared among groups using ANOVA. An average geometric model was generated, from which an optimal intramedullary (IM) nail curvature function was derived. Insertion of the derived optimal nail and of two currently-available commercial nails into the femur having the highest degree of curvature was then simulated via finite element methods.ResultsSubstantial variability in femoral curvature was observed among the population sample. Sex was found to correlate most strongly with femoral size; males tend to have larger femora than females. Although the average femoral radius of curvature for African Americans was slightly higher than for Caucasians, the difference was not statistically significant. Curvature did not vary across the sample by age, sex or race. Finite element analysis results simulating IM nail insertion using the geometrically-optimized nail showed a substantial decrease in von Mises stress when compared to tested commercially-available IM nails. Fracture was predicted within the posterior canal wall for commercially available nails, as the generated stresses exceeded the allowable stress of cortical bone, but not for the geometrically-optimized nail.ConclusionsConsidering variation in femoral geometry among patients when designing implantable fixation devices may be important. Femoral size differs between adults by sex, with males being larger than females. Pattern of curvature, however, did not differ, although there may be slight differences between European and African Americans. As such, the proposed average femoral curvature function calculated here may be sufficient for the entire population. According to finite element analysis, insertion-induced stresses in the femur were within the allowable range for the geometrically-optimized nail and appear more desirable than in other common nail designs.     

A biomechanical comparison of proximal femoral nails and locking proximal anatomic femoral plates in femoral fracture fixation: A study on synthetic bones

Background:The incidence of fractures in the trochanteric area has risen with the increasing numbers of elderly people with osteoporosis. Although dynamic hip screw fixation is the gold standard for the treatment of stable intertrochanteric femur fractures, treatment of unstable intertrochanteric femur fractures still remains controversial. Intramedullary devices such as Gamma nail or proximal femoral nail and proximal anatomic femur plates are in use for the treatment of intertrochanteric femur fractures. There are still many investigations to find the optimal implant to treat these fractures with minimum complications. For this reason, we aimed to perform a biomechanical comparison of the proximal femoral nail and the locking proximal anatomic femoral plate in the treatment of unstable intertrochanteric fractures.Result:Nail and plate models were locked distally at the same level. Axial steady load with a 5 mm/m velocity was applied through the mechanical axis of femur bone models. Axial loading in the proximal femoral intramedullary nail group was 1.78-fold greater compared to the plate group. All bones that had the plate applied were fractured in the portion containing the distal locking screw.Conclusion:The proximal femoral intramedullary nail provides more stability and allows for earlier weight bearing than the locking plate when used for the treatment of unstable intertrochanteric fractures of the femur. Clinicians should be cautious for early weight bearing with locking plate for unstable intertrochanteric femur fractures.     

Second generation intramedullary nailing of subtrochanteric femur fractures: a biomechanical study of fracture site motion

OBJECTIVES: To compare fracture site motion between different second-generation intramedullary nails used to fix subtrochanteric fractures of the proximal femur with and without femoral neck fractures. DESIGN: Nondestructive mechanical testing of four types of femoral intramedullary nails was undertaken to evaluate fracture site motion using a model that simulated single-leg and double-leg stance. METHODS: Three types of reconstruction nails (the Russell-Taylor Delta [Smith & Nephew, Memphis, TN], the Uniflex [Biomet, Warsaw, IN], Alta CFX [Howmedica-Osteonics, Rutherford, NJ]) and the Long Gamma nail (Howmedica-Osteonics, Rutherford, NJ), each measuring 11 x 380 mm, were inserted in fiberglass composite femurs. Four fracture patterns were studied (transverse subtrochanteric, subtrochanteric with posteromedial wedge comminution, subtrochanteric with one-centimeter gap, and a one-centimeter gap with a subcapital neck fracture). Single-and double-leg stance loading was simulated using a servohydraulic load frame (MTS, Eden Prairie, MN). Two-way analysis of variance and post hoc t tests were used to determine any statistically significant differences between groups. RESULTS: In single-leg stance there were significant differences in coronal plane rotation, shear, and axial translation across the subtrochanteric fracture site between the different nail types and the different fracture patterns (p < 0.001). In double-leg stance there were significant differences in coronal plane rotation and femoral head vertical motion between the different nail types and the different fracture patterns (p < 0.001), and there were significant differences in shear and axial translation between the different fracture patterns (p < 0.001) but not the different nail types (p > 0.05). CONCLUSIONS: For simple, well-reduced fractures the choice of implant is not critical. As fracture severity increased (comminution, gap, and combined neck fracture), the choice of implant, particularly with reference to proximal nail dimensions and implant materials, was a significant factor in reducing fracture site motion. Therefore, our laboratory data suggest that when subtrochanteric fractures are unstable (e.g., comminution, segmental bone loss) and early weight bearing is desirable, the choice of implant is critical and should be restricted to implants that allow minimal fracture site motion (Long Gamma and Russell-Taylor).     

Slotted intramedullary hip screw nails reduce proximal mechanical unloading

The current prospective and randomized study was done to determine whether fixation of intertrochanteric femoral fractures that lack a medial buttress with a dynamically locked intramedullary hip screw prevents proximal stress shielding. Stress shielding was evident by the presence of cortical hypertrophy at the level of the tip of the nail and often was associated with midthigh pain. Of the 80 patients enrolled in this trial, 64 still were alive after 1 year. Among these patients, 30 had the nail classically locked with two screws transfixing the nail in two separate holes (Group A), and 34 had the nail locked with one screw passing through a slot (Group B). The average duration of followup was 37 months (range, 12-49 months). Tolerance to dynamically locked nails was significantly better, with only one patient in Group B having cortical hypertrophy of the femur at the level of the tip of the nail, compared with six patients in Group A. Other outcomes were equal in both groups. Late tolerance to this new dynamically locked intramedullary hip screw is good, while retaining the known advantages of nailing of these fractures.     

Callus characteristics following intramedullary nailing with stainless steel or epoxy-carbon nails

Biological mechanical improvements of osteosynthesis make intramedullary nailing an attractive alternative to bone plate fixation. However, little is known about stress shielding induced by intramedullary implantation of a nail. To evaluate the effect of the nail rigidity on bone healing, mid-metatarsal osteotomies were performed in sheep and fixed with either stainless steel or epoxy-carbon composite V-shaped nails. Mechanical and histomorphometric features of the callus were evaluated 4 months postoperatively. No statistical difference between the two groups were demonstrated for either mechanical or microstructural characteristics. The presence of a fibrous membrane filling the bone/nail interface and allowing sliding micromotions of the implants and the much smaller effect of nail rigidity, as compared to bone plate after implantation, were assumed to be the main reason for this uniformity. At this stage of healing, bone characteristics were more related to a nonspecific (vascular) bone remodeling phenomenon than to a stress-shielding effect.     

The effect of implant overlap on the mechanical properties of the femur

BACKGROUND: The most biomechanically stable relationship between the side plate of a compression hip screw (CHS) and retrograde intramedullary (IM) femoral nail has not been described in the literature. This becomes a clinical issue when treating supracondylar femur fractures with a retrograde nail in patients with a history of compression hip screw fixation of intertrochanteric fractures. The proximal end of the nail and the interlocking screws may act as a stress riser in the femoral diaphysis. The purpose of this study is to determine the biomechanical consequences of the amount of implant overlap between a CHS plate and retrograde IM femoral nail. METHODS: Nine paired fresh-frozen cadaver femora from elderly donors were cleaned of soft tissue and fixed with uniaxial strain gauges. Each femur was loaded three times in a fall-loading configuration to 50 kg at a rate of 1 Hz. The study consisted of two phases. In phase 1, six pair were randomly divided into a control and test femur from each pair. Three states were compared on each test femur: uninstrumented, instrumented with CHS, and instrumented with CHS and retrograde nail. The control femur consisted of the matched femur tested in two states: uninstrumented and instrumented with a CHS. The femora were then loaded to failure. The tests were performed with the retrograde nail and CHS gapped 3 cm, kissing, and overlapping by two screw holes (two pair for each state). In phase 2, each of the remaining three pair were instrumented with a CHS and retrograde nail overlapping in one femur and gapped in the matched femur and tested in the same manner. Data analysis was performed using Pearson's correlation coefficients between groups. Paired samples t tests were used to compare differences within test states and independent samples t tests were used to compare differences between femora. Mean strain at 50-kg load, load-versus-strain patterns, failure patterns, and load and strain at failure were recorded. RESULTS; Correlation coefficients were greater than 0.98 within and between pairs (p < 0.001). There were statistically significant differences (p < 0.05) in strain patterns between the uninstrumented, CHS, and CHS/IM test states. The addition of a side plate significantly (p < 0.05) increased lateral compressive strains in the femoral diaphysis. Mean strain at 50-kg load was significantly (p < 0.05) altered by the addition of the retrograde nail in all three implant orientations. Gapped implants failed at lower loads and strains than femurs with kissing and overlapping implants. Gapped constructs failed at lower loads than control states. Overlapped constructs tolerated the highest loads and strains before failure. CONCLUSION: Strain patterns are altered by the degree of implant overlap in the proximal femoral diaphysis. Femora with uninstrumented intervals between retrograde nails and side plates fail at lower loads than femora without retrograde nails and those with kissing or overlapping implants. Kissing or overlapping instrumentation increases load to failure and creates a more biomechanically stable construct than gapped implants. The findings of this study suggest an overlapping implant orientation in the femur increases failure load at the implant interface.     

Triangular support intramedullary nail: A new internal fixation innovation for treating intertrochanteric fracture and its finite element analysis

BackgroundProximal femoral nail anti-rotation (PFNA) and Gamma nail were recommended for intertrochanteric fracture, however, with high rate of post-operation complications. The triangular support intramedullary nail (TSIN) was designed to reduce the risk of postoperative complications related to Gamma nail and PFNA, and the aim is to compare the biomechanical characters of Gamma nail, PFNA and TSIN for fixation of intertrochanteric fracture and prove the rationality of the concept of triangle fixation in the treatment of intertrochanteric fractures.MethodsThe finite element model of proximal femur was constructed according to the CT data of femur. Intertrochanteric fracture models with Evans type Ⅰ and Ⅳ were established and fixed with Gamma nail, PFNA and TSIN by UG-NX 12.0. The finite element analysis software was used to compare the stress distribution and displacement of three implants fixation models.ResultsUnder axial loading of 600 N, the peak stress and maximum displacement of intact proximal femur was 13.78 MPa and 1.33 mm, respectively. The maximum stress of TSIN for fixation of Evans type Ⅰ and Ⅳ intertrochanteric fractures was 86.23 MPa and 160.63 MPa which was significantly lower than that of Gamma nail and PFNA. The maximum relative displacement of fracture section in Gamma nail and PFNA fixation models was 0.18 mm and 0.19 mm which has 135% and 148% higher than in TSIN fixation models for fixing Evans type Ⅰ intertrochanteric fracture, and 0.47 mm and 0.59 mm which has 91% and 140% higher than in TSIN fixation models for stabilization of Evans type Ⅳ intertrochanteric fracture.ConclusionCompared with Gamma nail and PFNA fixation, TSIN has superior advantages in stress distribution and construct stability. We believe that triangle fixation concept help to reduce the risk of post-operative complications associated with PFNA and Gamma nail and improve the clinical effect of intertrochanteric fracture.     

InterTan髓内钉治疗不稳定型骨质疏松性股骨转子间骨折近期疗效

目的探讨股骨近端InterTan髓内钉治疗不稳定型髓内钉老年骨质疏松性股骨转子间骨折的近期临床疗效。方法对53例不稳定型的股骨转子间骨折使用InterTan髓内钉治疗。对术后并发症、负重行走时间、Harris髋关节评分、x线随访及骨折愈合时间等情况进行评估。结果53例均获随访,时间9～12（10．53±0．42）个月。术后Harris髋关节评分60～96（84．47±2．19）分,优良率79．25％;骨折愈合时间8～12（9．77±0．38）周。无股骨头颈部短缩、髋内翻、内植物周围骨折和内固定物失效、断裂发生。结论InterTan髓内钉治疗伴骨质疏松的不稳定型老年股骨转子间骨折并发症少,骨折愈合率高,近期临床疗效满意。     

股骨反转子间骨折PFNA内固定失败的影响因素分析

目的探讨股骨反转子间骨折股骨近端防旋性髓内钉(PFNA)内固定失败的影响因素。方法回顾性分析2015-02—2017-06间在安阳地区医院骨二科接受PFNA治疗的97例股骨反转子间骨折患者的临床资料,其中手术成功81例(成功组),失败16例(失败组)。比较2组患者的一般资料、临床指标,经单因素、多因素Logistic回归分析,得出影响PFNA内固定失败的因素。结果 2组患者的性别、年龄及髓内钉顶点距离位置比较,差异无统计学意义(P>0.05)。多因素Logistic回归分析结果显示,肥胖、基础疾病、骨质疏松程度、骨折分型、骨折复位情况,以及尖顶距可能是导致股骨反转子间骨折PFNA内固定失败的危险因素(P<0.05)。结论股骨反转子间骨折PFNA内固定失败的影响因素包括肥胖、基础疾病、重度骨质疏松、外侧壁过薄、不稳定性骨折、骨折复位欠佳及尖顶距过大等,应积极防治,以提高手术成功率。     

Femoral nailing for metastatic disease of the femur: a comparison of reamed and unreamed femoral nailing

A total of 73 consecutive intramedullary femoral nails were inserted for metastatic disease of the femur; 43 were reamed and 30 were solid nails. The two groups were similar with regards to age, type of primary tumour, anatomical site, acute or 'impending' fracture and postoperative survival. The 'solid' nail offers a satisfactory alternative form of stabilisation for metastatic disease of the femur with rates of implant failure which are comparable with the reamed nail. In this series bilateral nailing was not associated with any increase in mortality. Contrary to other reports, imposing a delay in patients with pain and a short life expectancy seems unjustified. The use of the 'solid' femoral nail does not prevent sudden death due to massive fat embolism.     

Unstable pertrochanteric femoral fractures

BACKGROUND: Fractures in the trochanteric region of the femur are classified as AO/OTA 31-A, as they are extracapsular. This report analyzes the relatively rare 31-A3 fracture, which has also been referred to as an "intertrochanteric femur fracture with subtrochanteric extension," "reverse obliquity intertrochanteric femur fracture," "unstable intertrochanteric femur fracture," or a "subtrochanteric femur fracture." The A3 fracture is characterized by having a fracture line exiting the lateral femoral cortex distal to the vastus ridge. Possible fixation constructs include compression hip screws, intramedullary hip screws, trochanteric intramedullary nails, cephalomedullary antegrade intramedullary nails, and 95 degrees plates. Most reports investigating 31-A fractures do not describe the 31-A3 fracture. For this analysis, only reports clearly indicating that the fracture treated was a 31-A3 were included. It should be understood that this approach therefore excludes reports on generic "subtrochanteric fractures" or "intertrochanteric fractures," some of which may have been 31-A3 fractures. OBJECTIVE: To determine the effect of fixation technique for the AO/OTA 31-A3 fracture on rates of union, infection, risk of reoperation, and functional outcomes.     

A prospective evaluation of the AO/ASIF universal femoral nail in the treatment of traumatic and reconstructive problems of the femur

Beginning in October 1986, we prospectively evaluated the AO/ASIF Universal Femoral Nail in the treatment of traumatic (89 nails) and reconstructive (11 nails) problems of the femur. For treatment of isolated femoral fractures, the mean time of patient positioning and nail insertion was 2.4 hours with a mean blood loss of 389 ml. Seventy-eight per cent of the patients were followed for a minimum of 12 months. There were no infections, one case of nail failure, two cases of screw fracture, and three nonunions. Sixteen nails have been uneventfully removed. The AO/ASIF femoral nail provides results comparable to other intramedullary interlocking devices.