Posterior Column Of Acetabulum Research Articles

Surgical treatment outcomes of acetabular posterior wall and posterior column fractures using 3D printing technology and individualized custom-made metal plates: a retrospective study

BackgroundFractures involving the posterior acetabulum with its rich vascular and neural supply present challenges in trauma orthopedics. This study evaluates the effectiveness of 3D printing technology with the use of custom-made metal plates in the treatment of posterior wall and column acetabular fractures.MethodsA retrospective analysis included 31 patients undergoing surgical fixation for posterior wall and column fractures of the acetabulum (16 in the 3D printing group, utilizing 3D printing for a 1:1 pelvic model and custom-made plates based on preoperative simulation; 15 in the traditional group, using conventional methods). Surgical and instrument operation times, intraoperative fluoroscopy frequency, intraoperative blood loss, fracture reduction quality, fracture healing time, preoperative and 12-month postoperative pain scores (Numeric Rating Scale, NRS), hip joint function at 6 and 12 months (Harris scores), and complications were compared.ResultsThe surgical and instrument operation times were significantly shorter in the 3D printing group (p < 0.001). The 3D printing group exhibited significantly lower intraoperative fluoroscopy frequency and blood loss (p = 0.001 and p < 0.001, respectively). No significant differences were observed between the two groups in terms of fracture reduction quality, fracture healing time, preoperative pain scores (NRS scores), and 6-month hip joint function (Harris scores) (p > 0.05). However, at 12 months, hip joint function and pain scores were significantly better in the 3D printing group (p < 0.05). Although the incidence of complications was lower in the 3D printing group (18.8% vs. 33.3%), the difference did not reach statistical significance (p = 0.433).ConclusionCombining 3D printing with individualized custom-made metal plates for acetabular posterior wall and column fractures reduces surgery and instrument time, minimizes intraoperative procedures and blood loss, enhancing long-term hip joint function recovery.Clinical Trial Registration12/04/2023;Trial Registration No. ChiCTR2300070438; http://www.chictr.org.cn.

Study of anatomical parameters and intraoperative fluoroscopic techniques for transiliac crest anterograde lag screws fixation of the posterior column of the acetabulum

BackgroundCurrently, there is a lack of research investigating the feasibility of employing anterograde lag screw fixation through the iliac crest for minimally invasive percutaneous treatment of the posterior acetabular column, which encompasses retrograde and anterograde screw fixation in posterior acetabular lag screw fixation. And consequently, the purpose of this study was to examine the anatomical parameters of anterograde lag screw fixation of the posterior column of the pelvis through the iliac crest as well as to investigate the intraoperative fluoroscopy technique, to furnish a scientific rationale supporting the practical utilization of this method within clinical settings.MethodsIn this study, pelvic CT data of 60 healthy adults, including 30 males and 30 females, were accumulated. The mimics 21.0 software was developed to reconstruct the three-dimensional pelvis model, simulate the anterograde lag screw fixation of the posterior column of the acetabulum through use of the iliac crest, and precisely identify the insertion point: Utilizing the widest iliac tubercle as the starting point, the insertion point was moved toward the anterior superior iliac spine by 1.0 cm at a time until it reached 4.0 cm. With a total of five insertion points, all oriented toward the lesser sciatic notch, the initial diameter of the virtual screw measured 5.0 mm, and it was progressively enlarged by 1.0 mm increments until reaching a final diameter of 8.0 mm. Besides, the longest lengths of virtual screws with distinct diameters at divergent entry points were measured and compared. At the same time, the intraoperative fluoroscopy technique for optimal access was analyzed.ResultsThe cross-section from the iliac crest to the lesser sciatic notch was irregular, with multiple curved shapes. Furthermore, the diameter of the screw was determined by the anteroposterior radians and width of the iliac crest plate, while the screw length was determined by the curvature of the square body. On the condition that the screw diameter of the D channel (3.0 cm outward from the widest part of the iliac tubercle to the lesser sciatic notch) was 5 mm, 6 mm as well as 7 mm, the longest screw lengths were (145.6 ± 12.8) mm, (143.6 ± 14.4) mm and (139.9 ± 16.6) mm, correspondingly, indicating statistically substantial distinctions from other channels (P < 0.0001). Intraoperative fluoroscopy demonstrated that the C-arm machine was tilted (60.7 ± 2.9) ° to the iliac at the entrance position and perpendicular to the D-channel at the exit position.ConclusionIt is possible to use the new channel to fix the posterior column of the acetabulum with an anterograde lag screw through the iliac crest. In specific, the channel is 3.0 cm outward from the widest part of the iliac tubercle to the lesser sciatic notch. Providing a wide channel, long screw insertion, and high safety, this technique offers a novel approach for minimally invasive treatment of posterior column fractures of the acetabulum.

Finite element analysis of posterior acetabular column plate and posterior acetabular wall prostheses in treating posterior acetabular fractures

BackgroundThe purpose of this study was to investigate the mechanical stability of the posterior acetabular column plate and different posterior acetabular wall prostheses used in treating posterior acetabular fractures with or without comminution.MethodsThe unilateral normal ilium was reconstructed, and a model of posterior acetabular wall fracture was established on this basis. The fracture fragment accounted for approximately 40% of the posterior acetabular wall. The posterior acetabular column plate and different posterior acetabular wall prostheses were also designed. Using static and dynamic analysis methods, we observed and compared the changes in the stress and displacement values of different models at different hip joint flexion angles under external forces.ResultsAt different hip flexion angles, the stress of each model mainly fluctuated between 37.98 MPa and 1129.00 MPa, and the displacement mainly fluctuated between 0.076 and 6.955 mm. In the dynamic analysis, the nodal stress‒time curves of the models were nonlinear, and the stress changed sharply during the action time. Most of the nodal displacement‒time curves of the models were relatively smooth, with no dramatic changes in displacement during the action time; additionally, most of the curves were relatively consistent in shape.ConclusionsFor simple posterior acetabular wall fractures, we recommend using a posterior acetabular column plate. In the case of comminuted posterior acetabular fractures, we recommend the use of a nonflanked posterior acetabular prosthesis or a biflanked posterior acetabular prosthesis. Regarding the method of acetabular prosthesis design, we propose the concept of “Break up to Make up” as a guide.

The placement of percutaneous retrograde acetabular posterior column screw based on imaging anatomical study of acetabular posterior column corridor

ObjectiveTo explore the entry point, orientation, and fixation range of retrograde acetabular posterior column screw.MethodThe computed tomography data of 100 normal adult pelvises (50 males and 50 females, respectively) were collected and pelvis three-dimensional (3D) reconstruction was performed by using Mimics software and the 3D model was imported into Geomagic Studio software. The perspective of acetabular posterior column was carried out orienting from ischial tuberosity to iliac fossa in the Mimics software. Virtual screw was inserted perpendicular to the transverse section of acetabular posterior column corridor, and the maximum screw diameter, entry point, orientation, exit point were measured. The screw fixation range, the easy-to-penetrate sites, and intraoperative optimal fluoroscopic views were assessed.ResultsThe acetabular posterior column corridor showed a triangular-prism shape. The virtual screw entry point was located at the midline between the medial and lateral edges of the ischial tuberosity. The distance between the entry point and the distal ischial tuberosity was around 13 mm. The distances between the exit point and the true pelvis rim, and ipsilateral anterior sacroiliac joint line were (19.33 ± 2.60) mm and (23.65 ± 2.42) mm in males, respectively. As for females, those two data were (17.63 ± 2.00) mm and (24.94 ± 2.39) mm, respectively. The maximum diameters of screws were (17.21 ± 1.41) mm in males and (15.54 ± 1.51) mm in females. The angle between the retrograde posterior column screw and the sagittal plane was lateral inclination (10.52 ± 3.04)° in males, and that was lateral inclination (7.72 ± 2.99)° in females. Correspondingly, the angle between the screw and the coronal plane was anterior inclination (15.00 ± 4.92)° in males, and that was anterior inclination (12.94 ± 4.72)° in females. Retrograde acetabular posterior column screw through ischial tuberosity can fix the acetabular posterior column fractures which were not 4 cm above the femoral head center. The easy-to-penetrate sites were located at the transition between the posterior acetabular wall and the ischium, the middle of the acetabulum, and 1 cm below the greater sciatic notch, respectively. The iliac oblique 10°, iliac oblique 60°, and obturator oblique 60° views were the intraoperative optimal fluoroscopic views to assess whether the screw was safely inserted.ConclusionRetrograde acetabular posterior column screw entry point is located at the midline between the medial and lateral edges of the ischial tuberosity, which is 1.3 cm far from the distal ischial tuberosity. The screw direction is about 10° lateral inclination and 15° anterior inclination, which can fix the acetabular posterior column fractures which were not 4 cm above the femoral head center.

A Rare Case : Traumatic Posterior Hip Dislocation Associated with Anterior Column and Incomplete Posterior Column Acetabular Fracture

Introduction: The hip is among the most solid joints within the human body that took a lot of force to dislocate it. Hip dislocation is frequently associated with acetabulum fracture. Although traumatic posterior hip dislocation is rarely involved anterior column fracture. Case Presentation: We describe a rare case of traumatic posterior dislocation of hip associated with anterior column and incomplete posterior column acetabular fracture in a young female following road traffic accident. The patient hip dislocation was reduced with closed reduction and perfomed open reduction and fixation under C-Arm for acetabular fracture management. Assessment of anterior and posterior acetabular column was revealed stable after fixation. The goals are to maximize the patient's ability to function, enable early recovery to function. The patient was able to flex her left hip at 6 weeks after the surgery. Conclusion: This case highlights a rare case of the traumatic posterior hip dislocation associated with anterior column and incomplete posterior column acetabular fracture, attempts to elucidate the mechanism of injury and perform prompt reduction to achieve a better patient outcome.

Biomechanical analysis of Magic screw fixation for acetabular posterior column fracture

This study aims to analyze the biomechanical stability of Magic screw in the treatment of acetabular posterior column fractures by finite element analysis. A three-dimensional finite element model of the pelvis was established based on the computed tomography (CT) and magnetic resonance imaging (MRI) data of a volunteer and its effectiveness was verified. Then, the posterior column fracture model of the acetabulum was generated. The biomechanical stability of the four internal fixation models was compared. The 500 N force was applied to the upper surface of the sacrum to simulate human gravity. The maximum implant stresses of retrograde screw fixation, single-plate fixation, double-plate fixation and Magic screw fixation model in standing and sitting position were as follows: 114.10, 113.40 MPa; 58.93, 55.72 MPa; 58.76, 47.47 MPa; and 24.36, 27.50 MPa, respectively. The maximum stresses at the fracture end were as follows: 72.71, 70.51 MPa; 48.18, 22.80 MPa; 52.38, 27.14 MPa; and 34.05, 30.78 MPa, respectively. The fracture end displacement of the retrograde tension screw fixation model was the largest in both states, and the Magic screw had the smallest displacement variation in the standing state, but it was significantly higher than the two plate fixations in the sitting state. Magic screw can satisfy the biomechanical stability of posterior column fracture. Compared with traditional fixations, Magic screw has the advantages of more uniform stress distribution and less stress, and should be recommended.

Favorable Outcome Twenty-Two Months after Delbet Type Ib Capital Femoral Transepiphyseal Fracture and Posterior Column Acetabular Fracture in a Fifteen-Year-Old Male

Case A fifteen-year-old male patient sustained a posteriorly dislocated right capital femoral Delbet type Ib epiphyseal fracture-separation and a right acetabular posterior column fracture after a low-energy trip and fall. The capital femoral epiphysis was closed reduced and fixed with cannulated screws on an urgent basis. He underwent acetabular osteosynthesis via a Kocher-Langenbeck approach two days thereafter. Twenty-two months after injury, he was weight-bearing on the right lower extremity without radiologic evidence of avascular necrosis or clinical evidence of pain or functional deficit. Conclusion Fracture-separation of the capital femoral epiphysis comprises only 8% of skeletally immature femoral neck fractures in the Delbet and Colonna classification. Prognosis is worse with ipsilateral hip dislocation due to the risk of avascular necrosis from disruption of the medial femoral circumflex artery. Urgent referral to a trauma center and treatment by appropriate specialists enables good long-term results after this uncommon traumatic injury pattern.

Finite element analysis of infra-acetabular screw fixation for the treatment of acetabular posterior column fracture.

Infra-acetabular screws have been described to increase the fixation strength of acetabular fractures with separation of the columns. Previous studies were based on the simulation of the anterior column fractures without modelling the biomechanical effect of the screw in the posterior column fractures. The purpose of this study was to compare the stability of different internal fixation models of posterior column fracture and to provide a theoretical basis for the clinical application of infra-acetabular screws. Five internal fixation models of acetabular posterior column fracture were simulated using five implants, including one reconstruction plate (PCP model), one posterior column screw (PCS model), one infra-acetabular screw (PIS model), one infra-acetabular screw and one reconstruction plate (PIS + PCP model), and one infra-acetabular screw and one posterior column screw (PIS + PCS model). After meshing, material parameter, and boundary condition settings, a vertical downward load of 500N was applied on the surface of the sacrum. To evaluate the biomechanical properties, the stress distribution and von Mises peak stress were recorded and analyzed, and the displacement distributions of the upper and lower fracture surfaces were compared. In model PCP, the maximum stress of the plate is 71.952MPa; in model PCS, the maximum stress of the screw is 52.740MPa; in model PIS, the maximum stress of the screw is 68.985MPa; in model PIS + PCP, the maximum stress of the plate is 64.695MPa and the maximum stress of the screw is 39.679MPa; and in model PIS + PCS, the maximum stress of the posterior column screw is 48.197MPa and the maximum stress of the infra-acetabular screw is 65.201MPa. The maximum stresses of implants are all located on the fracture surfaces. The average displacement differences of the upper and lower fracture surfaces are compared as follows: model PIS + PCS (0.03503mm) < model PIS + PCP (0.08205mm) < model PCP (0.10096mm) < model PCS (0.19007mm) < model PIS (0.23546mm). With sufficient biomechanical stability, infra-acetabular screws can be used as a supplementary fixation for the treatment of acetabular posterior column fractures. It is recommended to fix the fracture by the combined application of the infra-acetabular screw and posterior column screw.

Three-dimensional finite element analysis with different internal fixation methods through the anterior approach.

BACKGROUNDWith the modernization of society and transportation in the last decades in China, the incidence of high-energy trauma increased sharply in China, including that of acetabular fractures.AIMTo establish different finite element models for acetabular posterior column fractures involving the quadrilateral area of the acetabulum.METHODSThe three-dimensional models of the normal and fractured pelvis and the five internal fixations were established using the computed tomography data of the pelvis of a living volunteer. After the vertebral body model was inserted in the way of origin matching and all cancellous bones were copied using the duplicated cancellous bone model as the subtractive entity, the Boolean operation was performed on the pelvis model to obtain the model of the complete pelvis cortical and cancellous bones.RESULTSIn the standing position, the maximum stress was 46.21 MPa. In the sitting position, the sacrum bore the simulated gravity load at the upper end. When comparing the five fixations, there were no significant differences in the stress mean values among groups (sitting: P = 0.9794; standing: P = 0.9741). In terms of displacement, the average displacement of the internal iliac plate group was smaller than that of the spring plate group (P = 0.002), and no differences were observed between the other pairs of groups (all P > 0.05). In the standing position, there were no significant differences in the mean value of displacement among the groups (P = 0.2985). It can be seen from the stress nephogram of the internal fixations in different positions that the stress of the internal fixation was mainly concentrated in the fracture segment.CONCLUSIONThere were no significant differences among the fixations for acetabular posterior column fractures involving the quadrilateral area of the acetabulum.

A Quantitative Anatomic Study of Plate-Screw Fixation of the Acetabular Posterior Column through a Posterior Approach.

The aim of this study was to determine safe paths for screw placement on the posterior column of the acetabulum. A total of 25 male hemipelvises were utilized in this study. These hemipelvises were sectioned, and formed cross-sections A, B, C, D, and E. The length of the screw and screw posterior column angle of the entry points at cross-sections B, C, and D were measured. On the margin of the acetabulum, lateral middle 1/4 point, midpoint, medial middle 1/4 point, and medial margin of the posterior column of each cross-section, the safe entry angle of inclination is 39, 57, 74, 90, and 106°, respectively, and the length of the screw is 35.5 mm, 33 mm, 32 mm, 31 mm, and 74 mm, respectively. On the lateral 1/4 region, lateral middle 1/4 region, medial middle 1/4 region, and medial 1/4 region of the posterior column, the screw posterior column angle is 40 ~ 60°, 60 ~ 75°, 75 ~ 90°, and 90°~parallel to the quadrilateral plate, respectively, and the length of the screw is 30 mm.

Direct posterior approach for the treatment of posterior acetabular fractures

Objective To explore surgical technique and clinical results of the direct posterior approach (DPA) for acetabular fractures involving posterior column, posterior wall, or posterior column and wall. Methods From January 2016 to June 2017, data of 10 cases (7 males, 3 females, an average age of 37 years, ranging from 17 to 54 years) with posterior acetabular fractures treated by the DPA were retrospectively analyzed. Fractures were caused by traffic accident in 6 cases and by falling in 4 cases. According to Letournel-Judet classification of acetabular fractures, there were 6 cases of posterior acetabular wall fractures, 4 cases of posterior wall fractures involving posterior column. A straight skin incision was made from the middle of the line between the posterior margin of the tip of the femoral greater trochanter and the posterior superior iliac spine, to the posterior margin of the femoral greater trochanter. The gluteus maximus muscle was cleaved longitudinally. A view of the area from hip capsule to the superior margin of the greater sciatic foramen was obtained by entering along the interspace of the gluteus medius and pyriformis muscle, and the superior gluteal neurovascular bundle was protected. Acetabular posterior column and posterior wall fractures were reduced and fixed under direct vision. The fracture reduction, fracture healing, femoral head necrosis, sciatic nerve injury, superior gluteal neurovascular injury and heterotopic ossification were evaluated by the postoperative X-ray and CT examination. The function of hip joint was assessed by the Merle d’Aubigne-Posteal score modified by Matta. Results The average operative incision length was 9.6 cm (range, 8-11 cm). The average operation time was 50 min (range, 35-80 min). The average blood loss was 310 ml (range, 200-440 ml). The time of follow-up was 12-30 months. All the patients were healed within 8-12 weeks without any complications such as superior gluteal nerve injury, superior gluteal vessel injury, or sciatic nerve injury. One case of acetabular posterior wall and posterior column fracture with posterior dislocation of hip joint, suffered from femoral head necrosis at the 9th months after surgery, which was treated by total hip arthroplasty and was recovered one year after surgery. In one case of actebular posterior wall and posterior column fracture, heterotopic ossification occurred 3 month after operation, without any special treatment and the hip joint activity was not affected at the follow-up of 15 months after surgery. During the 12-month follow-up after surgery, the Merle d’Aubigne-Postel score modified by Matta was 13-18, among which there were excellent in 6 cases, good in 2, acceptable in 2, with an overall excellent and good rate of 80% (8/10). Conclusion The direct posterior approach for posterior acetabular fractures can obtain satisfactory clinical results. The advantages of the DPA include decreasing trauma, shortening operation time, reduing blood loss and decreasing risks of iatrogenic injury to the gluteus medius muscle, the external rotators, the arteriae circumflexa femoris medialis and sciatic nerves as well as reducing and fixing the fractures under direct vision. Thus, the DPA is a relatively safe surgical approach for acetabular posterior wall/column fracture. Key words: Acetabulum; Fractures, bone; Fracture fixation, internal

Application of a novel acetabular reduction clamp for treatment of acetabular posterior column fracture

Objective To investigate the effect of our self-developed acetabular reduction clamp in the treatment of fractures of acetabular posterior column. Methods The data were retrospectively analyzed of the 32 patients who had been treated for acetabular posterior column fractures using our self-developed acetabular reduction clamp at Department of Minimally Invasive Surgery, Zhengzhou Orthopaedics Hospital from August 2016 to June 2018. They were 17 males and 15 females, aged from 18 to 62 years (average, 41.3 years). According to the Letournel-Judet classification, there were 9 simple posterior column fractures, 14 posterior column plus posterior wall fractures, 4 T-shaped fractures and 5 double column fractures. The Kocher-Langenbeck (K-L) incision was used for simple posterior column and posterior column plus posterior wall fractures, and the K-L combined with anterior ilioinguinal approach for T-shaped and double column fractures. The displaced posterior column fracture was repositioned with our novel reduction clamp before pelvic reconstruction plate was used for fixation. The quality of fracture reduction, fracture union time, complications and hip function score at the last follow-up were recorded. Results This series of 32 patients were followed up for 7 to 20 months (average, 12.9 months). According to the Matta scores for fracture reduction at the last follow-up, 15 cases were excellent, 16 good and one poor, yielding an excellent and good rate of 96.9%. The fracture union time ranged from 3 to 6 months (average, 4.7 months). According to the modified Merle d＇Aubign scores at the last follow-up, hip function was excellent in 18 cases, good in 11 and fair in 3, yielding an excellent and good rate of 90.6%. Postoperative symptomatic distraction injury to the sciatic nerve appeared in 2 patients, postoperative wound lipid liquefaction developed in one and heterotopic ossification of Brooker grade Ⅱ was observed in 2 patients during follow-up. Conclusion In the treatment of acetabular posterior column fracture with open reduction and internal fixation with pelvic reconstruction plate through the K-L approach, our novel acetabular reduction clamp can be used safely and effectively to assist fracture reduction, leading to satisfactory results. Key words: Acetabulum; Fractures, bone; Fracture fixation, internal; Reduction

A simple reduction technique for the posterior column in acetabular fractures

Background Posterior acetabular column injuries can happen as an isolated fracture or can be associated with other acetabular fractures. The aim of this study was to evaluate the validity of a new technique in the reduction and fixation of fractures involving the posterior acetabular column. Patients and methods A prospective study which included 35 patients with displaced acetabular fractures (≥3 mm). Of the patients, 24 were men and 11 were women. The age of the patients’ ranged from 25 to 50 years with a mean of 37.9 years. All patients had injuries to the posterior column, either isolated or associated with other types of acetabular fractures. The follow-up period ranged from 24 to 36 months with a mean of 28.8 months. Results Perfect or anatomical reduction of the posterior column was achieved and maintained in 25 (71.43%) patients. Near perfect or near-anatomical reduction of the posterior column was achieved and maintained in another six (17.14%) patients. Three (8.57%) patients had good reduction of the posterior column which was maintained till union, while one (2.86%) patient had imperfect reduction of the posterior column. According to the Harris hip score, the clinical outcome was excellent in 12 (34.29%) patients, good in 17 (48.57%) patients, fair in five (14.29%) patients, and poor in one (2.85%) patient. The operative time for reduction and fixation of the posterior column using this technique ranged from 15 to 20 min with a mean of 18 min. No permanent complications happed during this study. Conclusion The technique described in this study is a simple technique for open reduction without the need for such bulky instrumentations with rapid internal fixation. This method of reduction and fixation is considered useful, safe, and comparable to all the previous described reduction and fixation techniques.

Incidence of sciatic nerve palsy associated with reconstruction plate fixation of posterior wall and posterior column of acetabulum through posterior approach and its prognosis

Incidence of sciatic nerve palsy associated with reconstruction plate fixation of posterior wall and posterior column of acetabulum through posterior approach and its prognosis

A new navigational apparatus for fixation of acetabular posterior column fractures with percutaneous retrograde lagscrew: Design and application.

The purpose of this study was to analyze the feasibility and accuracy of a newly developed guide apparatus for the percutaneous retrograde lag screw fixation of posterior column of acetabular fractures. 3D pelvic models were reconstructed from the helical computed tomographic data of 33 adult patients using the Mimics 10.01 software. The virtual cylindrical implants were placed along a line passing through the central point of the ischial tuberosity and the midpoint between the most prominent point of anterior superior iliac spine and that of posterior superior iliac spine. Some anatomical parameters were then measured, based on which a guide apparatus was developed, and its safety and accuracy were experimentally validated with pelvic and cadaveric specimens. The screws were successfully placed in all of the 66 hemipelves. There was a significant difference between the male and female groups in the AB distance (156.26 ± 7.28 mm and 151.38 ± 8.11 mm), OI distance (139.53 ± 7.56 mm and 125.15 ± 11.17 mm), and diameter (12.19 ± 1.97 mm and 10.19 ± 2.14 mm) of the virtual cylindrical implants. This guide apparatus was proved effective for percutaneous retrograde lag screw fixation of posterior column acetabular fractures by the experiments with the pelvic and cadaveric specimens. Screw fixation of posterior column fractures via OI is safe and feasible. We designed a new percutaneous retrograde screw fixation guide apparatus to assist internal fixation of posterior column acetabular fracture.

Digital analysis and certification of osseous pathway for anterograde screwing in acetabular posterior column

Objective To analyze and determine the optimal osseous pathway for anterograde screwing in the acetabulum posterior column. Methods Recruited for this study were 40 healthy adult volunteers, 20 males and 20 females, aged from 18 to 56 years (average, 34.6 years). Firstly, their abdomen CT scanning images were transformed into Materialise Mimics Innovation Suite 16.0 software to obtain the 3D reconstruction images of the pelvis (.stl file). The Imageware 12.0 software (EDS, USA) was used to produce the optimal osseous pathway for anterograde screwing in the acetabulum posterior column. The diameter and length of the pathway were measured and statistically analyzed. Secondly, after 10 adult fresh pelvic specimens were scanned, the optimal osseous pathway for anterograde screwing in the acetabulum posterior column was determined in the same way as the above. A navigation template for anterograde screwing in the acetabular posterior column was manufactured. The screwing in the posterior column of the acetabulum was conducted using Kirschner wire with the aid of the navigation template. Imaging evaluation was performed after fixation. Results The projection of the safe zone in the acetabular posterior column was irregularly triangle; there were no significant differences regarding the projection size between different ages (P>0.05). The maximum diameter and the maximum length of the left optimal pathway in males were respectively 22.37±1.42 mm and 131.27±3.63 mm, and those of the right optimal pathway in males respectively 23.16±1.39 mm and 129.23±3.27 mm. The maximum diameter and the maximum length of the left optimal pathway in females were respectively 17.58±1.83 mm and 112.56±2.77 mm, and those of the right optimal pathway in females respectively 16.92±1.66 mm and 114.41±2.98 mm. There were no significant differences between the left and right sides for the same item in the same gender (P>0.05).There were significant differences between males and females for the same item in the same side (P<0.05). No penetration into the cortex or the hip joint happened. Conclusion The optimal osseous pathway for anterograde screwing in the acetabulum posterior column can be determined by digital techniques, leading to a simple and safe procedure for the treatment of fractures of the acetabular posterior column. Key words: Acetabulum; Fractures, bone; Fracture fixation, internal; Bone nails; Imaging, three-dimensional

Therapeutic efficacy of Kocher-Langenbeck approach without cutting hip spin short muscle tendons for treatment of acetabular posterior column fractures

Objective To investigate the feasibility and clinical effect of Kocher-Langebeck(K-L)approach without cutting the short external rotator muscles of hip for treatment of cetabular posterior column fractures. Methods A retrospective case series study was performed on 28 patients with acetabular fractures admitted from June 2015 to February 2017.There were 23 males and 5 females, averagely aged 43.6 years (range, 26-71 years). According to the Letournel classification, there were 9 patients with simple fractures, 14 back wall and back pillar fractures and 5 cross fractures. All patients were combined with posterior dislocation. The patients were given tibial tubercle traction after hip joint reduction in the hospital. During the surgery, K-L approach was adopted without cutting the short external rotator muscles of hip. Operation duration and intraoperative bleeding were recorded. Visual analogue score (VAS) was recorded before and after operation. The X-ray at 1 day, 6 weeks, 3 months and 1 year after operation were reviewed to evaluate fracture healing time. Matta criteria were used to assess the surface flatness of joint. The modified Merle d'Aubigne-Postel scoring system was applied to evaluate the function of hip joint. Intraoperative and postoperative complications were recorded. Results The operation duration was 76-120 min (mean, 94 min), and the intraoperative blood loss was 120-320 ml (mean, 265 ml). All patients were followed up for average 16 months (range, 10-24 months). Preoperative VAS was 5-10 points[(7.5±1.3)points], and 0-3 points[(0.9±0.8)points] 6 months after operation (P<0.01). All fractures healed and the average healing duration was 10.1 weeks (range, 6-12 weeks). According to the Matta criteria, 24 patients were graded excellent and 4 good, with excellence rate of 100%. According to the modified Merle d'Aubigne-Postel grading system, clinical results were graded excellent in 23 patients, good in 5, with excellence rate of 100%. Transient sciatic nerve injury occurred in 3 patients after surgery, and the nerve function of these patients fully recovered within 3 months after operation. There were no infection, heterotopic ossification and other complications. The wound healing was good, without liquefaction or cracking. Sciatic nerve injury was found in five patients, three of whom were performed with a transient lesion and recovered within 3 months. Conclusion In the posterior pathway surgery for acetabular posterior column fractures, the K-L approach without cutting the short external rotator muscles of hip can be used to complete the internal fixation with a high rate of fracture healing, sound reduction outcome, satisfactory functional recovery and few complications. Key words: Acetabulum; Hip fractures; Fracture fixation, internal

Clinical experience with three-dimensional printing techniques in orthopedic trauma.

To report our experiences with the use of three-dimensional (3D) printing in the field of orthopedic trauma. This retrospective study enrolled 24 patients from three university teaching hospitals in whom 3D printing technique was applied: 14 patients with acetabular fractures and 10 patients with clavicular shaft fractures. We summarized our experiences with 3D printed bone models. Three-dimensional printed acetabular models improved understanding of complex acetabular anatomy and fracture pattern to plan the optimal positioning of a reduction clamp and the trajectory of screws. Pre-bending of a reconstruction plate could reduce operative time. We also recorded fluoroscopic images of a simulated surgery for percutaneous screw fixation of the acetabular posterior column, with the optimal positioning of the guide wire determined during the simulation used as a reference during the actual operation. This surgical simulation was performed by a resident and served as a helpful training method. For fractures of the clavicle, we identified the optimal position of anatomical plates using 3D printed clavicle models. In our experience, 3D printing technique provided surgeons with improved understanding of the fracture pattern and anatomy and was effectively used for preoperative planning, education of surgical trainees, and performing simulations to improve intra-operative technical outcomes.

Safety of screw placement on the medial iliosciatic plate for acetabular posterior column: a comparison between males and females by 3D reconstruction technique

Objective To compare the safe zone and safe angles between males and females for screw placement on the medial iliosciatic plate for acetabular posterior column using 3D reconstruction technique. Methods Normal pelvic CT scans of 52 adults (27 males and 25 females; aged from 18 to 74 years, averaging 47.2 years) were obtained to create pelvic 3D models. After the acetabulum was thickened by 5 mm, the width (d) of the safe zone for placement of the medial iliosciatic plate was measured. After the vertical distance (w) between the vertex of the obturator canal and the greater sciatic notch was measured, the ratio (r) of d/w was calculated. The recombined innominatum model was cut through the center of the ac-etabulum with a plane perpendicular to the quadrilateral plate and the greater sciatic notch. The cross-section was marked as M. In males, 4 points at distances of 1.0 cm, 1.5 cm, 2.0 cm and 2.5 cm anterior to the greater sciatic notch were marked. At the 4 points, the angulations (∠a, ∠b, ∠c and ∠d) between the quadrilateral plate and the tangent line of the outer edge of the thickened acetabulum model were measured on the cross-section M. In females, 3 points at distances of 1.0 cm, 1.5 cm and 2.0 cm anterior to the greater sciatic notch were marked before ∠a, ∠b, and ∠c were measured. The differences in the above parameters were compared between males and females. Results The width (d) of the safe zone for placement of the medial iliosciatic plate was 28.56±2.44 mm in males and 24.36±2.47 mm in females; the ratio (r) was 0.61±0.07 in males and 0.54±0.05 in females. The safe angulations for screw placement in males, ∠a, ∠b, ∠c and ∠d, were 88.04°±3.18°, 77.81°±3.85°, 68.01°±4.11° and 56.81°±4.81° while those in females, ∠a, ∠b and ∠c, were 91.29°±4.52°, 76.23°±3.82° and 62.79°±3.51°, respectively. There were statistically significant differences between males and females in values of d, r, ∠a and ∠c (P< 0.05). Conclusions In fixation of acetabular posterior column fractures using medial iliosciatic plate, the differences between males and females should be taken into account. Besides, specific safe angles should be chosen according to the position of the plate. Key words: Acetabulum; Bone plates; Bone nails; Imaging, three-dimensional

Designation and Validation of a Posterior Anatomical Plate for the Anterior Column of the Acetabulum.

BackgroundSurgical treatment of acetabular fractures is one of the greatest challenges for orthopedic surgeons. Fixation of most displaced fractures requires extensive exposure, which may lead to complications, including blood loss, neural or vascular injury, postoperative infection, wound healing problems, and heterotopic bone formation.Material/MethodsThis study was conducted to certify an anatomic plate with an anterior column lag screw guiding device to repair the posterior acetabulum. Complete pelvic spiral computed tomography (CT) scan data were collected from 56 patients. The posterior column of the acetabulum was simulated with a lag screw. The guiding device for the plate was designed by measuring the position of the screw point and the direction and maximum diameter of the screw.ResultsThe distance from the screw point to the apex of the greater sciatic notch was farther in women than in men. The distance from the screw point to the ischial spine was also farther in women than in men. The θ angle (front inclination angle) of the screw was lower in women than in men. The ϕ angle (camber screw angle) was greater in women than in men. The success rate when using the guided device was significantly higher than when using traditional pedicle screws.ConclusionsThe guided device was very useful for improving placement success and accuracy rates of the acetabular posterior anatomical anterior column plate using antegrade lag screws, and for reducing surgical risk and injury.