Comparative strength of three methods of fixation of transverse acetabular fractures.

With the advent of percutaneously placed lag screws for fixation of acetabular fractures, this study evaluated the strength of lag screw fixation compared with traditional fixation techniques of transverse acetabular fractures. Ten formalin-treated human, cadaveric pelvic specimens with bilateral, transtectal transverse acetabular fractures were used for this study. The right acetabular fractures were fixed with a five-hole plate and four screws with the central hole spanning the posterior fracture site. The left acetabular fractures were fixed with two lag screws, one each in the anterior and posterior columns, or with a screw and wire construct stabilizing both columns. The specimens were loaded to implant failure. Stiffness, yield strength, maximum load at failure, and site of failure was recorded. The plate and screw construct showed significantly greater yield and maximum strength when compared with the two lag screws. The stiffness of the lag screw method was 39% higher than that of the plating method, but this result was not statistically significant. In addition, the plate and screw method provided significantly greater maximum strength than the screw and wire technique. The quadrilateral plate seemed to be the weakest area of fixation because 83% of the implant failures occurred in this region. In patients in whom the risks of formal open reduction and internal fixation of acetabular fractures outweigh the possible benefits, such as in patients with burns or degloved skin, the advent of computer-assisted and fluoroscopically guided percutaneous surgical techniques have been instrumental. This study showed there is greater strength of fixation with a plate and screw construct, possibly secondary to supplementary fixation distal to the quadrilateral plate. However, lag screw fixation provided relatively greater stiffness, which may account for its clinical success. Percutaneous lag screw fixation of appropriate transverse acetabular fractures is a viable option.     

Transgluteal posterior column screw stabilization for fractures of the acetabulum: a technical trick

SUMMARY:: The traditional exposure of high posterior column or transverse acetabular fractures can pose a challenge for lag screw stabilization. The authors describe an adjunctive percutaneous transgluteal lag screw technique for the internal fixation of the high posterior column. In the senior author's experience, this technique has been helpful to achieve the optimal trajectory for a stable perpendicular lag screw to maintain an anatomical reduction. In our experience, this technique has been used in conjunction with the standard Kocher-Langenbeck exposure and posterior column plating techniques.     

The use of a 3D-printed personalised drill guide for posterior column lag screw fixation in displaced transverse acetabular fracture: A case report

Introduction and importanceAnterior column plate combined with posterior column screws have been effectively used for treatment of displaced transverse acetabular fractures. This article presents the use of 3D-printed technology for customising a guide template to appropriately place posterior column screw.Case presentationA 50-year-old female suffered displaced juxtatectal fracture of the right acetabulum. A personalised guide for antegrade posterior column screw placement was designed based on the data of her pelvic CT-scan. This guide and a prototype of her right acetabulum - created by mirroring the intact left acetabulum - were 3D-printed for preoperative evaluation and pre-contouring of reconstruction plate. Modified Stoppa approach and additional lateral window were used for direct reduction, anterior column plate and posterior column lag screw fixation. Post-operative CT-scan showed good reduction and nearly ideal screw position.Clinical discussionAnterior column plate and antegrade posterior column screw could provide joint stability and early mobilisation for displaced transverse acetabular fractures. However, determination of optimal entry point, direction and length for screw insertion is still technically demanding. The 3-D reconstruction images of hemipelvic specimen allowed us to identify the safe bone corridor, design a drill guide to put the proper guide pin and conduct preoperative trial. All those resulted in appropriate real screw fixation with reduction of soft tissue damage, X-ray exposure and time of operation.ConclusionThe use of 3D-printed personalised guide for posterior column screw fixation is a promising alternative option for treatment of displaced transverse acetabular fracture where 3D-navigation system is not available.     

A biomechanical study of conventional acetabular internal fracture fixation versus locking plate fixation

Background

Conventional internal fixation entails the use of an interfragmentary lag screw along with a plate. Not all acetabular fractures are amenable to the placement of an interfragmentary lag screw, and the fracture may be displaced during tightening of the interfragmentary lag screw. Locking plates are a possible solution. We sought to determine whether a locking plate construct can provide stability equivalent to that provided with a conventional construct for transverse acetabular fractures.

Methods

We used 5 paired fresh-frozen cadaveric acetabula. We fixed one side with the conventional technique and the other side with a locking plate. We subjected each fixation to a cyclic compressive force up to 500 cycles, followed by compressive force until failure. We monitored 3-dimensional motion of the fracture.

Results

The average fracture gap at 50 N compressive force after 500 loading cycles was 0.41 (standard deviation [SD] 0.49) mm for the conventional plate and lag screw construct compared with 0.76 (SD 0.62) mm for the locked plate construct (p = 0.46). The force to failure, as defined by 2 mm of fracture gap, was 848 (SD 805) N for the conventional plate and lag screw construct compared with 506 (SD 277) N for the locked plate fixation (p = 0.34).

Conclusion

The locking plate construct is as strong as the conventional plate plus interfragmentary lag screw construct for fixing transverse acetabular fractures. Locking plates may improve management of acetabular fractures by eliminating the need for placement of an interfragmentary lag screw. Furthermore, they may be helpful in revision hip arthroplasty in patients with pelvic discontinuity.     

Screw placement in percutaneous acetabular surgery: gender differences of anatomical landmarks in a cadaveric study

Purpose

Percutaneous reduction and periarticular screw implantation techniques have been successfully introduced in acetabular surgery. The advantages of this less invasive approach are attenuated by higher risks of screw misplacement. Anatomical landmarks are strongly needed to prevent malplacement. This cadaver study was designed to identify reliable anatomical osseous landmarks in the pelvic region for screw placement in acetabular surgery. Gender differences were specifically addressed.

Methods

Twenty-seven embalmed cadaveric hemipelvic specimens (13 male, 14 female) were used. After soft-tissue removal, anterior and posterior column acetabular screw placement was conducted by one orthopaedic trauma surgeon under direct vision. Each column was addressed by antegrade and retrograde screw insertion. Radiographic verification of ideal screw placement was followed by assessment of the distance from the different entry points to adjoining anatomical osseous structures.

Results

For anterior column screw positioning, the posterior superior iliac spine (PSIS), posterior inferior iliac spine (PIIS), iliopectineal eminence and centre of the symphysis were most reliable regarding gender differences. For posterior column screw positioning, the distance to the anterior superior iliac spine (ASIS) and the ischial tuberosity showed the lowest deviation between the different gender specimens. Highest gender differences were seen in relation to the cranial rim of the superior pubic ramus in retrograde anterior column screw positioning (p = 0.002). Most landmarks could be targeted within a 2.5-cm range in all specimens.

Conclusions

The findings emphasise the relevance of osseous landmarks in acetabular surgery. By adhering to easily identifiable structures, screw placement can be safely performed. Significant gender differences must be taken into consideration during preoperative planning.     

Guidance for Treatment of Pelvic Acetabular Injuries with Precise Minimally Invasive Internal Fixation Based on the Orthopaedic Surgery Robot Positioning System

Pelvic acetabular fracture is a common kind of fracture, mostly caused by high energy injuries. It is associated with high mortality and disability rates. The aim of surgical treatment of pelvic acetabular fractures is to restore the symmetry and stability of the pelvic ring structure and the anatomical structure of acetabular. Open reduction internal fixation is often used for the treatment of such fractures, but open surgery is in cases of serious injury, more bleeding, and high risk of infection. With the development of minimally invasive technology and the concept of the bone channel structure, the percutaneous lag screw technique for the treatment of pelvic and acetabular fractures has been applied in clinical practice and has proven to be effective. However, the anatomical structure of the pelvis and acetabulum is complex, and there are many important nerves and vessels adjacent to it. Traditional fluoroscopy screw placement is prone to screw malposition, and even minor angle changes may lead to screw perforation and damage of nerve vessels. The problem of radiation exposure is also noteworthy. Robotic‐assisted surgery can be used to carry out screw position planning through preoperative imaging, intraoperative real‐time tracking, and mechanical arm assistance to ensure that the screw placement position is consistent with the planning. In this way, robotic‐assisted surgery can be used to accurately insert lag screws, and can reduce surgical risk and radiation exposure. This guide uses the TiRobot system as an example to describe the application of robot surgery in detail, aiming at standardizing the application of robots in orthopaedic surgery.     

髋臼后部骨折顺行拉力螺钉固定进钉导航模板的可行性研究

 目的 探讨导航模板辅助顺行拉力螺钉固定髋臼后部骨折的可行性与实用性。方法 收集40例正常成人骨盆的螺旋 CT 扫描数据,导入Mimics　10.01软件重建骨盆三维模型。选取左侧半骨盆模型,经过坐骨结节沿着髋臼后柱纵轴置入虚拟圆柱体。调整圆柱体位置,确定最佳进钉点,分别测量进钉点到弓状缘、骶髂关节最前缘的最短距离、圆柱体与冠状面夹角α、四方区与髂翼所在平面的夹角β。以stl格式导出模型,UG 6.0软件打开骨盆三维模型,定位参考平面。根据测量得到的进钉解剖学参数,确定后柱螺钉的最佳钉道。提取方形区及髂窝的表面解剖学形态,建立与方形区解剖学形态一致的模板。设计出带有3个进钉孔的左侧髋臼导航模板模型,运用UG软件镜像功能生成右侧髋臼导航模板模型,利用快速成形技术生成实体模型。取16具(男7例、女9例)干燥的人体左侧骨盆标本,模拟从不同的进钉孔进行髋臼后柱螺钉的置入,验证导航模板辅助进钉的准确性。结果 成功地设计并制作出与四方区解剖结构较一致的导航模板。不同的进钉孔进钉成功率：进钉孔1,6.3％(1具)准确定位、75％(12具)良好定位、18.7%(3具)失败;进钉孔2,81.3％(13具)准确定位、18.7％(3具)良好定位;进钉孔3,37.5％(6具)准确定位、62.5％(10具)失败。结论　根据髋臼后柱拉力螺钉进钉解剖学参数设计的导航模板可以准确地辅助拉力螺钉的置入。     

髋臼后柱安全置钉的临床解剖学研究

目的 探讨髋臼后柱的解剖结构,以寻求-安全的置钉途径.方法 取15具骨盆标本(共30髋),确定髋臼缘最上点为A点,最下点为B点,取其A、B中点为C点.取坐骨大切迹顶点为A'点,坐骨棘顶点为B'点,取A'、B'中点为C'点.连接C、C'两点.经过C、C'线且与后柱表面垂直的平面为起始平面(髋臼中部平面).平行于起始平面,在起始平面上下各作2个横断面,段面间隔为10mm.共获得包括髋臼前柱、后柱在内的5个断面.在每一断面上测量髋臼宽、后柱宽并测量距髋臼缘10、20mm处置入螺钉的安全角度和长度.测量结果用(x±s)表示.结果 ①髋臼中部平面髋臼最宽为:(20.7±1.5)mm.但该断面后柱最窄为:(33.9±2.5)mm.②距髋臼后缘10mm的各断面进钉的最小角度为(52.3±5.5)°,最小进钉长度为(28,9±2,7)mm.距髋臼后缘20mm的各断面进钉的最小角度为(81.4±5.0)°,最小进钉长度为(35.9±4.1)mm.结论 在髋臼后柱距臼缘10、20mm处角度分别不大于50°、80°,深度分别不大于28、35mm可以安全的放置螺钉.     

Application of computer-generated stereolithography and interpositioning template in acetabular fractures: a report of eight cases

To determine the effectiveness of stereolithography modeling technologies in the surgical treatment of complex acetabular fractures, five patients with a complex fracture of the acetabulum and three patients with posterior wall fractures were considered in this study. The patients were surgically treated using an interposition template for accurate positioning of the fixation plate and screw trajectories. Intraoperative fluoroscopy confirmed precise plate placement and that all screw trajectories missed the hip joint. Fluoroscopy was only needed for confirmation of fracture reduction and for confirmation of screw location. Application of a life-size stereolithographic model of the pelvis and an interpositioning template along with the computer model of the reversed nonfractured contralateral hemipelvis provides an effective means for preoperative planning and accurate fixation of acetabular fractures. Further studies with this type of preplanning equipment may show a decrease in operative time and morbidity, decrease in radiation exposure, and improvement in accuracy of plate and screw placement.     

经腹直肌外侧入路钢板结合后柱拉力螺钉内固定治疗髋臼前后柱骨折

目的探讨经腹直肌外侧切口入路钢板结合后柱拉力螺钉内固定治疗髋臼前后柱骨折的临床疗效。方法回顾性分析自2011-03—2015-10采用经腹直肌外侧切口入路前柱钢板加后柱顺行拉力螺钉内固定治疗髋臼前后柱骨折48例的临床资料,术后根据改良的Merle D'Aubigne和Postel评价标准评价患侧髋关节功能。结果本组48例均为单一经腹直肌外侧切口入路完成手术,手术时间45~150 min,平均85 min;术中出血180~1 200 ml,平均330 ml;所有患者均获得随访10~24个月,骨折均愈合,髋臼前后柱骨折均复位良好,髋臼后柱拉力螺钉位置理想。复位标准按照Matta标准进行评估:优34例,良8例,可6例,优良率87.5%。2例出现腹壁伤口皮下脂肪液化,经换药后愈合。末次随访疗效根据改良的Merle D'Aubigne和Postel评分系统评定:优30例,良10例,可8例,优良率83.3%。结论经腹直肌外侧切口入路能从骨盆内侧面充分显露髋臼前柱、四方体及后柱,并直视下复位髋臼前后柱骨折,前柱钢板+后柱顺行拉力螺钉固定能达到稳定的固定效果。     

Computer-assisted periacetabular screw placement: Comparison of different fluoroscopy-based navigation procedures with conventional technique

The current gold standard for operatively treated acetabular fractures is open reduction and internal fixation. Fractures with minimal displacement may be stabilised by minimally invasive methods such as percutaneous periacetabular screws. However, their placement is a demanding procedure due to the complex pelvic anatomy. The aim of this study was to evaluate the accuracy of periacetabular screw placement assessing pre-defined placement corridors and comparing different fluoroscopy-based navigation procedures and the conventional technique.For each screw an individual periacetabular placement corridor was preoperatively planned using the planning software iPlan CMF^© 3.0 (BrainLAB). 210 screws (retrograde anterior column screws, retrograde posterior column screws, supraacetabular ilium screws) were placed in an artificial Synbone pelvis model (30 hemipelves) and in human cadaver specimen (30 hemipelves). 2D- and 3D-fluoroscopy-based navigation procedures were compared to the conventional technique. Insertion time and radiation exposure to specimen were also recorded. The achieved screw position was postoperatively assessed by an Iso-C^3D scan. Perforations of bony cortices or articular surfaces were analysed and the screw deviation severity (difference of the operatively achieved screw position and the preoperatively planned screw position in reference to the pre-defined corridors) was determined using image fusion.Using 3D-fluoroscopy-based navigation, the screw perforation rate (7%) was significantly lower compared to 2D-fluoroscopy-based navigation (20%). For all screws, the deviation severity was significantly lower using a 3D- compared to a 2D-fluoroscopy-based navigation and the conventional technique. Analysing the posterior column screws, the screw deviation severity was significantly lower using 3D- compared to 2D-fluoroscopy-based navigation. However, for the anterior column screw, the screw deviation severity was similar regardless of the imaging method. Despite the advantages of the 3D-fluoroscopy-based navigation, this method led to significantly longer total procedure and fluoroscopic times, and the applied radiation dose was significantly higher.Percutaneous periacetabular screw placement is demanding. Especially for posterior column screws, due to a lower perforation rate and a higher accuracy in periacetabular screw placement, 3D-fluoroscopy-based navigation procedure appears to be the method of choice for image guidance in acetabular surgery.     

Are Quadrilateral Surface Buttress Plates Comparable to Traditional Forms of Transverse Acetabular Fracture Fixation?

Background

Several construct options exist for transverse acetabular fracture fixation. Accepted techniques use a combination of column plates and lag screws. Quadrilateral surface buttress plates have been introduced as potential fixation options, but as a result of their novelty, biomechanical data regarding their stabilizing effects are nonexistent. Therefore, we aimed to determine if this fixation method confers similar stability to traditional forms of fixation.

Questions/purposes

We biomechanically compared two acetabular fixation plates with quadrilateral surface buttressing with traditional forms of fixation using lag screws and column plates.

Methods

Thirty-five synthetic hemipelves with a transverse transtectal acetabular fracture were allocated to one of five groups: anterior column plate + posterior column lag screw, posterior column plate + anterior column lag screw, anterior and posterior column lag screws only, infrapectineal plate + anterior column plate, and suprapectineal plate alone. Specimens were loaded for 1500 cycles up to 2.5x body weight and stiffness was calculated. Thereafter, constructs were destructively loaded and failure loads were recorded.

Results

After 1500 cycles, final stiffness was not different with the numbers available between the infrapectineal (568 ± 43 N/mm) and suprapectineal groups (602 ± 87 N/mm, p = 0.988). Both quadrilateral plates were significantly stiffer than the posterior column buttress plate with supplemental lag screw fixation group (311 ± 99 N/mm, p < 0.006). No difference in stiffness was identified with the numbers available between the quadrilateral surface plating groups and the lag screw group (423 ± 219 N/mm, p > 0.223). The infrapectineal group failed at the highest loads (5.4 ± 0.6 kN) and this was significant relative to the suprapectineal (4.4 ± 0.3 kN; p = 0.023), lag screw (2.9 ± 0.8 kN; p < 0.001), and anterior buttress plate with posterior column lag screw (4.0 ± 0.6 kN; p = 0.001) groups.

Conclusions

Quadrilateral surface buttress plates spanning the posterior and anterior columns are biomechanically comparable and, in some cases, superior to traditional forms of fixation in this synthetic hemipelvis model.

Clinical Relevance

Quadrilateral surface buttress plates may present a viable alternative for the treatment of transtectal transverse acetabular fractures. Clinical studies are required to fully define the use of this new form of fixation for such fractures when accessed through the anterior intrapelvic approach.     

Neurovascular injuries in acetabular reconstruction cage surgery: an anatomical study

Acetabular reconstruction cages are indicated for severe combined segmental and cavitary acetabular bone defects. The purpose of this study was to evaluate the implications of screw placement and drill plunge and the potential insult to anatomical structures when implanting acetabular reconstruction cages. A segmental cavitary defect was reamed into the acetabulum and a cage was implanted in each of the 10 hemipelvises. The relative course of the superior gluteal neurovascular bundle was mapped to assess dissection intervals. When cage screws were placed at least 15 mm longer than needed, 13% and 20% of screws of the superior flange and anterior rim hit the femoral nerve, respectively, and approximately 60% of the screws placed in the posterior rim endangered the obturator nerve. A "safe zone" for screw size may be a 15- and 25-mm screw for the superior flange and posterior rim, respectively.     

髋臼后柱拉力螺钉内固定的临床解剖学研究

目的研究髋臼后柱拉力螺钉内固定螺钉的最佳进钉点、方向和长度。方法取12个骨盆标本,其中男7个,女5个。於双侧髋臼中部垂直于前后柱表面截骨,逆行法沿后柱中心打入一克氏针,其从髂窝的穿出点为P点,作参考线AB,其中A为骶髂关节最前缘,B为髂前下棘基底下缘,由P点向AB作垂线,与AB相交于D点,然后测量以下数值:1.测量AB、AD、PD的距离;2.测量仰卧位时后柱克氏针与水平面的夹角α,与矢状面的夹角β;3.测量髋臼后柱截面的半径;4.测量后柱克氏针在骨皮质内的长度。结果PD是AB的中垂线。PD的距离男性为1.62±0.23cm,女性为1.51±0.10cm;夹角α男性为24.3±2.0°,女性为24.0±1.3°;夹角β男性为25.9±3.1°,女性为14.7±2.0°;后柱截面半径男性为10.18±1.24mm,女性为8.57±0.82mm;后柱克氏针长度男性为11.6±0.8cm,女性为10.2±0.5cm。结论髋臼后柱拉力螺钉内固定是可行的。     

髋臼后壁骨折三种内固定方式的生物力学研究及临床意义

背景：锁定重建接骨板已应用于髋臼后壁骨折的治疗,但关于其固定髋臼后壁骨折生物力学稳定性的研究报道甚少。目的：比较锁定重建接骨板、重建接骨板及单纯拉力螺钉固定髋臼后壁骨折的生物力学稳定性。 方法：取成人新鲜半骨盆标本18个,制成髋臼后壁骨折模型,随机分成三组。A组用2枚拉力螺钉固定,B组用重建接骨板固定,C组用锁定重建接骨板固定。进行轴向加载实验,测定各组骨折的纵向位移、内固定失效时的载荷及轴向刚度,以比较各内固定方式的稳定性。 结果：在相同载荷下,B组、C组骨折的纵向位移小于A组,B组、C组内固定失效时的载荷及轴向刚度大于A组,有统计学差异（P＜0.05）;B组与C组在纵向位移、内固定失效时的载荷及轴向刚度之间无统计学差异（P＞0.05）。 结论：锁定重建接骨板与重建接骨板的内固定稳定性优于单纯拉力螺钉内固定,锁定重建接骨板与重建接骨板内的固定稳定性相似,均可用于髋臼后壁骨折的内固定治疗。     

髋臼前柱螺钉固定解剖学研究及导向器的设计

目的为经髋臼前柱螺钉固定提供解剖学依据。方法对22只成人尸体骨盆标本,共44侧髋臼进行解剖学研究,观测髋臼前柱横断面形状,测量髋臼前柱螺钉固定在髂骨翼外侧面的进针点、进针方向、钉道直径、进针点至闭孔沟的距离。结果髋臼前柱横断面呈近似直角三角形,钉道直径10.5±0.8mm;螺钉进针点位于髂骨翼后外侧面坐骨大切迹和髂前上棘连线上方9.2±2.4mm,距坐骨大切迹38.5±3.8mm;螺钉进针方向于水平面与中心线夹角为40.7±3.8°,矢状面向尾端成角54.2±5.5°。钉道长度84.1±6.2mm。并设计出髋臼前柱螺钉固定导向器。结论髋臼前柱可接受1枚直径6.5mm、长70mm的螺钉,螺钉进针点位于髂骨翼后外侧面坐骨大切迹和髂前上棘连线上方10mm,距坐骨大切迹40mm。螺钉进针方向于水平面与中心线夹角40°,矢状面向尾端成角55°。髋臼前柱螺钉固定导向器将提高前柱螺钉固定的安全性。     

Screw-augmented fixation of acetabular components: A mechanical model to determine optimal screw placement

Sixteen embalmed hemipelves were used to determine the optimal acetabular screw placement to provide maximal screw pull-out strength in unicortical and bicortical screw fixation. The anterior column, superior ilium, posterior column, ischium, and pubis regions of the pelvis were tested using 6.5-mm titanium alloy screws and a hydraulic servo-controlled 1321 Instron testing machine. Force vs displacement data were acquired. Bicortical fixation was stronger than unicortical fixation in the four zones compared. This difference was significant in the superior ilium, posterior column, and ischium. The anterior column could not accept unicortical screws due to inadequate bone depth, which ranged between only 6 mm and 10 mm. Bicortical fixation was significantly greater in the superior ilium, posterior column, and ischium than in the anterior column or pubis. Unicortical fixation was greatest in the superior ilium. This information may aid decisions concerning the positioning of screws to augment acetabular component fixation.     

Is there a role for percutaneous pelvic and acetabular reconstruction?

The primary goal in the treatment of pelvic fractures is the restoration of haemodynamic stability. The secondary goal is the reconstruction of stability and symmetry of the pelvic ring. Percutaneous reconstruction can only be accepted if these goals are met. The type of definitive surgery is dependent of the degree of instability of the anterior and posterior pelvic ring. Retrograde transpubic screw fixation of pubic rami fractures is a good alternative to external fixation or plate and screw osteosynthesis. The technique of screw placement and image intensifier control is explained. Internal fixation of pure sacroiliac dislocations, fracture-dislocations of the sacroiliac joint and sacral fractures can be fixed with sacroiliac screws, placed percutaneously. Reduction of the fracture or dislocation is performed closed, or open if anatomy cannot be restored in a closed manner. The primary goal in the treatment of acetabular fractures is to restore anatomy. Reduction comes before fixation. The goal of minimising approaches cannot be more important. In most cases open reduction will be necessary to achieve anatomical reconstruction. Only the experienced acetabular surgeon will be able to decide when and how he can restore anatomy through a less invasive approach or with a percutaneous procedure. The anterior column screw can be inserted through a separate incision in addition to a Kocher-Langenbeck approach. It is the same screw as the retrograde transpubic screw but placed in the opposite direction. The posterior column screw is placed percutaneously from the lateral cortex of the ilium in the direction of the posterior column. Techniques of placement of both screws are demonstrated. Open reduction and internal fixation remains the standard of care in stabilisation of pelvic and acetabular fractures. Only the experienced surgeon will be able to judge if percutaneous procedures can be an alternative or a useful additive to conventional techniques.     

双柱拉力螺钉固定治疗横断髋臼骨折

目的　回顾分析双柱拉力螺钉固定治疗横断髋臼骨折的疗效。方法　 1 3例髋臼横断骨折分别采用Smith Peterson入路或者后外侧K -L入路结合前侧髂腹股沟入路行切开复位 ,前后柱拉力螺钉沿其功能轴固定。术后平均随访 4年 2个月 ,按照美国矫形外科医师协会 (AAOS)标准评估患髋功能。结果　 1 3例中 1 2例获解剖复位 ,1例复位欠佳。术中、术后无严重并发症。患髋术后功能优良率为 85 %。结论　双柱拉力螺钉固定技术是一种治疗髋臼横断骨折的有效方法 ,但技术要求较高 ,应严格掌握手术适应证     

Is the fracture morphology in the sagittal plane important in determining the ideal placement of the lag screw in intertrochanteric femoral fractures?: Ideal lag screw placement in intertrochanteric fractures in the sagittal plane

ObjectiveThe aim of this study was to determine the ideal placement of the lag screw taking into account the fracture morphology in the sagittal plane.Materials and methodsThree different morphology of fractures were created on the sagittal plane in femur models obtained in 3D CT scanning: posteriorly angled (Type A), transverse (Type B) and anteriorly angled (Type C). The lag screw was applied in each of the three fracture morphology as neutral, anteverted and retroverted in the sagittal plane. The nine models created were transferred to the Ansys Workbench program and analyzes were performed.ResultsIn Type A fracture, the stress value at the lag screw apex increase as the lag screw placement changes from the anteverted position to the retroverted position. It decreases in the Type B and Type C fractures. As the lag screw placement is changed towards the anteverted position, the stress at the lag screw-nail junction decreases in the Type A fracture and increases in the Type C fracture . There is no significant change in the Type B fracture. As the lag screw placement is changed towards the anteverted position, the stress in the calcar region increases in Type A fractures and decreases in Type C fractures. There is no significant change in type B fractures.ConclusionWhile the ideal lag screw placement in a type A fracture in the sagittal plane is the retroverted placement, the anteverted placement is ideal placement in type C fractures. Fracture morphology in the sagittal plane should be taken into account in the lag screw placement.