Minimally invasive screw fixation is as stable as anterior plating in acetabular T-Type fractures - a biomechanical study

[Minimally invasive stabilization of acetabular fractures with virtual navigation combined with robot-assisted 3D imaging]

OBJECTIVE

Minimally invasive stabilization of non- and minimally displaced acetabular fractures using intraoperative, robot-assisted three-dimensional (3D) imaging and a navigation system.

INDICATIONS

Nondisplaced or only minimally displaced fractures of the acetabulum.

CONTRAINDICATIONS

Comminuted and highly displaced fractures of the acetabulum, protrusion of the femoral head into the pelvis with the need for open reduction, lack of possibility of intraoperative navigation.

SURGICAL TECHNIQUE

After supine positioning the patient, the patient-side navigation reference is attached to the anterior superior iliac spine using a Schanz screw. The 3D scan and registration of the dataset in the navigation system can then be performed. This allows the 7.3 mm screws to be planned using 3D imaging and then implanted through minimally invasive incisions.

POSTOPERATIVE MANAGEMENT

After successfully implanting the screws using the minimally invasive surgical technique, the patient can be mobilized the following day with pain-adapted physiotherapy exercises. Full weight bearing is usually possible.

RESULTS

Between 2015 and 2023, 101 patients were treated using minimally invasive and navigation-assisted screw osteosynthesis for acetabular fractures. In 2 patients, a secondary screw dislocation occurred in the hip joint after mobilization, which required revision surgery with repositioning of the screw osteosynthesis and a hip arthroplasty, respectively. Minimally invasive navigated screw osteosynthesis, thus, offers adequate treatment of nondisplaced and minimally displaced acetabular fractures. Attention must be paid to the correct indication and surgical technique.

Acetabular posterior column screws via an anterior approach

Screw fixation of acetabular column fractures is a well-established alternative option to plate fixation providing comparable biomechanical strength and requiring less surgical exposure. For displaced acetabular fractures involving both columns open reduction and plate fixation of one column in combination with a column-crossing screw fixation of the opposite column via a single approach is a viable treatment option. Preoperative planning of posterior column screws (PCS) via an anterior approach is mandatory to assess the eligibility of the fracture for this technique and to plan the entry point and the screw trajectory. The intraoperative application requires fluoroscopic guidance using several views. A single view showing an extraarticular screw position is adequate to rule out hip joint penetration. The fluoroscopic assessment of cortical perforation of the posterior column requires several oblique views such as lateral oblique views, obturator oblique views and axial views of the posterior column or alternatively intraoperative CT scans. The application of PCS via an anterior approach is a technically demanding procedure, that allows for a relevant reduction of approach-related morbidity, surgical time and blood loss by using a single approach.

The "Metaizeau trick" to facilitate medullary pubic ramus screw insertion: A technical note

Minimally invasive procedures have recently seen an increase in the treatment of pelvic ring disruptions and select acetabular fractures. Similar to ilio-sacral screws, the superior pubic ramus screw is becoming a preferred method for treating unstable pelvic ring fractures. While the osteology of the superior pubic ramus is well understood and has inherent variability, standard screw insertion techniques work effectively in most cases. If the anatomy prevents the standard approach, there are alternative methods that can be employed for successful screw placement, or there might be a need for an open reduction and internal fixation with plates. Such techniques can be material-intensive and time-consuming. In this paper, we introduce a straightforward method that utilizes the Metaizeau nail as a guide wire to facilitate screw insertion in most instances, termed the "Metaizeau trick". Metaizeau nails, commonly found in trauma centers, are designed to locate a pathway effortlessly using this method. LEVEL OF EVIDENCE: IV.

Primary stability of multi-hole acetabular cup combined with posterior column plating for the fixation of complex acetabular fractures in elderly patients: a biomechanical analysis

BACKGROUND

Acute total hip arthroplasty has gained increasing popularity in the treatment of complex acetabular fractures in elderly patients, but the biomechanical evidence is lacking. Therefore, we measured the primary stability to evaluate whether acute total hip arthroplasty using a multi-hole acetabular cup and posterior column plating through a single K-L approach can safely be used for treating complexed acetabular fractures in the elderly.

METHODS

In 18 composite osteoporotic hemipelves, T-type acetabular fractures were treated in three ways: CSP (Cup with acetabular screws augmentation combined with posterior plate) group, CP (Cup without acetabular screw combined with posterior plate) group and CSPA (Cup with acetabular screws combined with posterior plate and anterior plate) group. Each specimen was dynamically loaded (300 to 1700 N, 1 Hz). Primary stability of the acetabular cup and fracture gap was evaluated by 3-dimensional (3D) micromotions.

RESULTS

No significant differences in the 3D-micromotions were observed among the CSP, CP and CSPA groups except the test point on the anterior column of the acetabulum in the CP scenario (CSP 49.33 ± 21.08 μm vs. CP 224.83 ± 52.29 μm, p < 0.001; CSPA 45.50 ± 12.16 μm vs. CP 224.83 ± 52.29 μm, p < 0.001). No significant differences in the fracture gap displacement on the posterior column of acetabulum were observed among the CSP, CP and CSPA groups.

CONCLUSION

Our results show, that acute total hip arthroplasty using a multi-hole cup with acetabular screws and posterior column plating through single a K-L approach offers good primary stability to allow good osseous integration for treating complex acetabular fractures in the elderly. Furthermore, it also provides good fracture gap displacement on the posterior column.

Hidden blood loss and the influential factors after minimally invasive treatment of posterior pelvic ring injury with sacroiliac screw

BACKGROUND

To analyze the perioperative bleeding and hidden blood loss (HBL) of sacroiliac screw minimally invasive treatment of pelvic posterior ring injury and explore the influential factors of HBL after operation for providing reference for clinical treatment.

METHOD

A retrospective analysis was conducted on data from 369 patients with posterior pelvic ring injuries treated with sacroiliac screws internal fixation at our hospital from January 2015 to January 2022. The research was registered in the Chinese Clinical Trial Registry in July 2022 (ChiCTR2200061866). The total blood loss (TBL) and HBL of patients were counted, and the factors such as gender, age, and surgical duration were statistically analyzed. The influential factors of HBL were analyzed by multiple linear regression.

RESULTS

The TBL was 417.96 ± 98.05 ml, of which the visible blood loss (VBL) was 37.00 ± 9.0 ml and the HBL was 380.96 ± 68.8 ml. The HBL accounted for 91.14 ± 7.36% of the TBL. Gender, surgical duration, fixed position, and fixed depth had significant effects on the HBL (P < 0.05).

CONCLUSIONS

The HBL was the main cause of anemia after minimally invasive treatment of posterior pelvic ring injury with a sacroiliac screw. Gender, surgical duration, fixed position, and fixed depth were closely related to the occurrence of HBL. In clinical treatment, we should consider these influential factors and take effective measures to reduce the impact of HBL on patients.

Functional Outcomes and Their Influencing Factors for the Surgical Management of T-type Acetabulum Fractures: A Prospective Single-Centre Study of 73 Patients

Introduction T-type fractures of the acetabulum are uncommon injuries, typically resulting in poorer long-term outcomes compared to other patterns of acetabular fractures. Our main purpose is to analyse the epidemiology, functional outcomes, and factors affecting the functional outcomes of patients with T-type acetabular fractures. Methods This prospective, single-centre study included 73 patients with T-type and T with posterior wall acetabular fractures. They underwent treatment with open reduction internal fixation using plating through the modified Stoppa, Kocher-Langenbeck (KL), or dual approach. The post-operative reduction was assessed according to Matta's criteria, and functional outcomes were evaluated using the modified Harris hip score. Results Between September 2017 and January 2023, 53 patients underwent surgery for T-type fractures (72.6%), and 20 patients were treated for T with posterior wall acetabular fractures (27.4%). The minimum follow-up period was one year, with a mean follow-up of 3.5 years. Anatomical reduction emerged as the major contributing factor towards good functional outcomes compared to satisfactory reduction according to Matta's criteria (P value: 0.006). Overall, 65 patients (89%) achieved excellent to good modified Harris hip scores, while eight patients (11%) obtained fair to poor scores. Patients with T-type fractures demonstrated better functional outcomes compared to T with posterior wall fractures (P value: 0.031). Conclusion Anatomical reduction, as assessed by Matta's reduction criteria, serves as a predictor of favourable functional outcomes. T with posterior wall fractures exhibit poor outcomes in comparison to T-type fractures. The surgical approach employed does not influence the reduction or the final functional outcome of the patient.

The use of a plate for fixation of the acetabulum

This study aimed to share our experience of a self-developed plate for acetabular fracture fixation through the presentation of clinical cases. Eight patients with complex acetabular fractures (Letournel classification) underwent surgery using a modified Stoppa approach and the novel plate design between 2021 and 2023 at the National Scientific Center for Traumatology and Orthopedics. Criteria such as the mechanism of injury, type of fracture, surgical approach, intraoperative and postoperative complications, quality of reduction, and functional and radiological results were evaluated. All patients included in the study presented complex types of acetabular fractures according to the Letournel classification. In all cases, surgical interventions were performed using a modified Stoppa approach. The assessment of reduction quality was conducted based on the radiological standards established by Matta. The reduction in quality was excellent in two patients, good in four, and satisfactory in two. One patient developed a post-traumatic false joint requiring additional surgery. The remaining patients achieved fracture healing with satisfactory Harris Hip Score (HHS) scores, indicating good overall function. The results of the self-developed plate for acetabular fracture fixation in our series were satisfactory.

Comparison between Novel Anatomical Locking Guide Plate and Conventional Locking Plate for Acetabular Fractures: A Finite Element Analysis

The treatment of complex acetabular fractures remains a complicated clinical challenge. Our self-designed novel anatomical locking guide plate (NALGP) has previously shown promising potential in T-shaped acetabular fractures (TAF), but a direct comparison with conventional fixations is yet to be made. The TAF model was established based on a volunteer's computer tomography data and then fixed with double column locking plates (DLP), a posterior column locking plate with anterior column screws (LPACS), and our NALGP. Forces of 200 N, 400 N, and 600 N were then loaded on the model vertically downward, respectively. The stress distribution and peaks and maximum displacements at three sites were assessed. We found that the stress area of all three plates was mainly concentrated around the fracture line, while only the matching screws of the NALGP showed no obvious stress concentration points. In addition, the NALGP and DLP showed significantly less fracture fragment displacement than the LPACS at the three main fracture sites. The NALGP was found to have less displacement than DLP at the posterior column and ischiopubic branch sites, especially under the higher loading forces of 400 N and 600 N. The fixation stability of the NALGP for TAF was similar to that of DLP but better than that of LPACS. Moreover, the NALGP and its matching screws have a more reasonable stress distribution under different loads of force and the same strength as the LPACS.

Talon cannulated compression device as an alternative in the fixation of acetabulum posterior column fractures: A biomechanical study

To compare the amount of displacement and rigidity at the fracture line under static & dynamic axial loading and torsional stress of conventional cannulated screw (CS), plate screw fixation including inter-fragmentary screw (PL), and talon cannulated compression device or talon screw in other words (TS) in posterior column fracture models. Synthetic hemipelvis bone models presenting a posterior column fracture were used in this study. Group PL, CS, and TS were created with ten bone models prepared for each group for dynamic and static loading tests and another ten for torsional tests. Rigidity and displacement amounts before and after loading were measured at the reference points AL, BL, and CL, located at the acetabulum's top, middle, and bottom, respectively. Torsional tests for each group were used to calculate torsional rigidity and maximum torque values. In dynamic axial loading tests, Group CS showed more displacement than PL at the BL point (p = 0,032) and Group TS at AL (p = 0,032) and CL (p = 0,004) points. In static axial loading tests, Group CS significantly displaced more than TS at AL and CL points (p = 0,05 and p = 0,014, respectively). Group PL and Group TS exhibited similar behavior in dynamic, static axial loading tests and torsional rigidity. The maximum torque that Group PL could withstand was statistically significantly higher than the other two groups (p <0,001). Talon cannulated screws had promising results in posterior column fractures of the acetabulum, which may decline the need for open surgery for stable fixation.

Is the T-shaped acetabular fracture really likes a "T"? A study based on three-dimensional fracture mapping

OBJECTIVES

To explore the morphological pattern of T-shaped acetabular fractures (T-SAFs) by mapping the fracture line using 3D software.

MATERIAL AND METHODS

We retrospectively reviewed 1298 consecutive patients with acetabular fractures, and a total of 56 T-SAF patients were enrolled. After the simulated reduction of each fracture in the software, the fracture lines of all patients were overlaid and plotted on a template. A frequency heat map was generated according to the differences in fracture line density distribution. According to the location of fracture lines, all cases were divided into three groups: posterior group, anterior group, extra-posterior group. In surgically treated patients, the surgical approach, fixation methods, and reduction quality were recorded or evaluated.

RESULTS

The transverse fracture line was sinuous without involving the acetabular roof, and the longitudinal fracture line sloped forward or backward along the edge of the acetabular fossa to split the obturator foramen. The anterior and posterior edges of the acetabular fossa, the transition zone of the acetabular roof and anterior wall, the transition zone of the superior pubic ramus and anterior wall, and the posterior wall near the greater sciatic notch were areas with high rates of fracture incidence. The posterior group included 26 patients (46.4%) and the distribution of fracture lines resembled a "T" or "Y". The anterior group included 25 patients (44.6%) and the distribution of fracture lines resembled a "7″. The extra-posterior group included 5 patients (8.9%) and the fracture lines run through the ischial body. The surgical strategies vary among different groups of T-SAF patients.

CONCLUSION

Our findings shed light on the characteristics of fracture lines for T-SAFs and provide a reference for surgical treatment strategies.

A new modified pararectus approach and visualization: an anatomical study

INTRODUCTION

The aim of our study was to visualize all the windows used in the pararectus approach with detailed cadaver images to facilitate better understanding of orthopedic surgeons and, in addition, was to modify the incision used in the pararectus approach to a more cosmetic bikini incision.

MATERIALS AND METHODS

In total, 20 cadavers fixed in 10% formalin were used in this study. Of these cadavers, 14 were male and six were female, with a mean age at death of 57 (42-82 years). The four windows were defined as follows in all the cadavers: pubic, quadrilateral, sacroiliac, and iliac windows.

RESULTS

The most important structure at risk in the pubic window was the corona mortis, as it was observed in 12 (60%) cadavers. In men, the spermatic cord was an important structure at risk in the pubic window. The obturator vessels and nerves were the structures at most risk in the quadrilateral window due to their close location with the quadrilateral surface. The obturator nerve on the medial side and at the entrance of the pelvis through the linea terminalis and lumbosacral truncus were the structures at most risk close to the sacroiliac joint in the sacroiliac window.

CONCLUSION

This anatomical study includes highly instructive visual shapes and cadaver images for the acetabulum and pelvis, whose anatomical structures are quite complex. We have found that this modified pararectus approach provides excellent access to the internal pelvic rim.

CLINICAL RELEVANCE

The anatomical data regarding the modified pararectus approach in this study will assist orthopedic surgeons in the surgical management of acetabular and pelvic fractures.

Biomechanical analysis of fixation methods in acetabular fractures: a systematic review of test setups

Purpose

Optimal anatomical reduction and stable fixation of acetabular fractures are important in avoiding secondary dislocation and osteoarthritis. Biomechanical studies of treatment options of acetabular fractures aim to evaluate the biomechanical properties of different fixation methods. As the setup of the biomechanical test can influence the experimental results, this review aimed to analyze the characteristics, comparability and clinical implications of studies on biomechanical test setups and finite element analyses in the fixation of acetabular fractures.

Methods

A systematic literature research was conducted according to the PRISMA guidelines, using the PubMed/MEDLINE and Web of Science databases. 44 studies conducting biomechanical analyses of fixation of acetabular fractures were identified, which met the predefined inclusion and exclusion criteria and which were published in English between 2000 and April 16, 2021. The studies were analyzed with respect to distinct parameters, including fracture type, material of pelvis model, investigated fixation construct, loading direction, loading protocol, maximum loading force, outcome parameter and measurement method.

Results

In summary, there was no standardized test setup within the studies on fixation constructs for acetabular fractures. It is therefore difficult to compare the studies directly, as they employ a variety of different test parameters. Furthermore, the clinical implications of the biomechanical studies should be scrutinized, since several test parameters were not based on observations of the human physiology.

Conclusion

The limited comparability and restricted clinical implications should be kept in mind when interpreting the results of biomechanical studies and when designing test setups to evaluate fixation methods for acetabular fractures.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00068-022-01936-9.

Novel minimally invasive tape suture osteosynthesis for instabilities of the pubic symphysis: a biomechanical study

INTRODUCTION

Open book fractures are challenging injuries oftentimes requiring surgical treatment. The current treatment of choice is symphyseal plating, which requires extensive surgery and entirely limits physiological movement of the symphyseal joint, frequently resulting in implant failure. Therefore, we investigated the biomechanical properties of a semi-rigid implant (modified SpeedBridge^™) as a minimally invasive tape suture construct for the treatment of open book fractures and evaluated the superiority of two techniques of implementation: criss-cross vs. triangle technique.

MATERIALS AND METHODS

Nine synthetic symphyseal joints were dissected creating an open book fracture. The different osteosynthesis methods (plating, modified SpeedBridge^™ in criss-cross/triangle technique) were then applied. All constructs underwent horizontal and vertical loading, simulating biomechanical forces while sitting, standing and walking. For statistical analysis, dislocation (mm) and stiffness (N/mm) were calculated.

RESULTS

Symphyseal plating for the treatment of open book fractures proved to be a rigid osteosynthesis significantly limiting the physiological mobility of the symphyseal joint (dislocation: 0.08 ± 0.01 mm) compared to the tape sutures (dislocation: triangle technique 0.27 ± 0.07 mm, criss-cross technique 0.23 ± 0.05 mm) regarding horizontal tension (p < 0.01). Both modified SpeedBridge^™ techniques showed sufficient biomechanical stability without one being superior to the other (p > 0.05 in all directions). Considering vertical loading, no statistical difference was found between all osteosynthesis methods (caudal: p = 0.41; cranial: p = 0.61).

CONCLUSIONS

Symphyseal plating proved to be the osteosynthesis method with the highest rigidity. The modified SpeedBridge^™ as a semi-rigid suture construct provided statistically sufficient biomechanical stability while maintaining a minimum of symphyseal movement, consequently allowing ligamental healing of the injured joint without iatrogenic arthrodesis. Furthermore, both the criss-cross and the triangle technique displayed significant biomechanical stability without one method being superior.

Double column acetabular fractures fixation using a novel dynamic anterior plate-screw system: A biomechanical analysis

BACKGROUND

According to the classification of Judet and Letournel, all double column acetabular fractures will certainly involve the disruption of the quadrilateral plate (QLP). Accurate reduction and reliable fixation of QLP is the key to obtain a normal congruent hip joint and avoid postoperative arthritis. The aims of this study were to assess the biomechanical properties of a novel dynamic anterior plate-screw system (named DAPSQ) and to compare its biomechanical stability with buttress-plate construct.

METHODS

Double column acetabular fractures involving the QLP were created on cadaveric pelvic specimens and subsequently stabilized with (1) a pre-contoured side-specific DAPSQ titanium plate and 4 quadrilateral screws (Group A) or a 12-hole suprapectineal pelvic reconstruction plate combined with a 9-hole 1/3 tube buttress plate (Group B). These constructs were mechanically loaded on ZwickZ 100 testing machine. Construct stiffness and displacement amounts of the two fixation methods in the condition of dynamic axial loading conditions were measured.

RESULTS

As the axial loading force increased from 200 N to 800 N, the longitudinal displacement of each pelvic specimen increased linearly and Group B was found to have significantly higher displacement than Group A (p<0.05). In the 600 N physiological loading, the construct stiffness values of Groups A and B were 139.4 ± 37.4 N/mm and 101±18.3 N/mm, respectively. Group A is 27% stiffer than Group B(p<0.05).

CONCLUSIONS

In this in vitro biomechanical study, DAPSQ plate and quadrilateral screws fixation of a double column acetabular fracture involving the QLP resulted in a better fixation construct than the traditional suprapectineal pelvic reconstruction plate and 1/3 tube buttress plate fixation.

A new internal fixation technique for acetabular fractures involving the quadrilateral plate

BACKGROUND

The treatment of acetabular fracture involving the quadrilateral plate is a technical challenge, and the optimal management of the fracture remains controversial. We have designed a new implant (named acetabular fracture reduction internal fixator, AFRIF) for acetabular fractures involving the quadrilateral plate. This use of this new device was not investigated therefore we conducted a retrospective study aiming to determine whether the AFRIF can achieve satisfactory clinical and radiological outcomes for quadrilateral plate fracture.

HYPOTHESIS

The AFRIF for quadrilateral plate fracture is an acceptable option to treat acetabular fracture involving the quadrilateral plate.

MATERIALS AND METHODS

We performed a retrospective analysis of prospectively collected data on 24 patients (15 males and 9 females) with acute displaced quadrilateral plate fractures of the acetabulum who were treated by the AFRIF between August 2011 and May 2015. The mean age of the patients was 61.5±9.2 years (range, 31-82 years). All hips had protrusion of the femoral head, of these 5 hips with associated articular impaction of the medial roof. The type of fractures included anterior column in 4, anterior column+posterior hemitransverse in 3, associated both column in 11, T-shaped in 6 patients. The approaches included Limited Ilioinguinal (5 patients) and Limited Standard-Ilioinguinal combined with Kocher-Langenbeck (19 patients). Quality of reduction was evaluated and graded as anatomical (0mm to 1mm of displacement), imperfect (2mm to 3mm displacement) or poor (more than 3mm displacement) according to the residual displacement as defined by Matta. The final follow-up clinical outcome was classified as excellent (18 points), good (15-17 points), fair (13-14 points) or poor (<13 points) in terms to the modified Merle d'Aubigné-Postel score, and radiological outcomes evaluation were as excellent, good, fair, or poor based on Matta score.

RESULTS

The mean duration of follow-up was 45.7±13.0 months (range, 24-60 months). Average operative time and bleeding amount was 110.3±30.8min (range, 105-210min) and 950.6±348.6ml (range, 300-1500ml), respectively. There was anatomical reduction in 17 patients (17/24, 70.8%), imperfect in 5 patients (5/24, 20.8%), and poor in 2 patients (2/24, 8.3%). All of the quadrilateral plate fractures achieved anatomical except one imperfect reduction. No re-protrusion of the femoral head was observed at the final follow-up. The mean modified Merle d'Aubigné-Postel score was 16.9±2.0 points (range, 10-18 points), and 83.3% (20 of 24) have good or excellent radiological outcomes.

DISCUSSION

The findings suggest that the AFRIF for quadrilateral plate fractures may prevent protrusion of the femoral head and achieve good to excellent clinical and radiological outcomes.

LEVEL OF EVIDENCE

IV, retrospective study.

Biomechanical comparison of minimally invasive treatment options for Type C unstable fractures of the pelvic ring

BACKGROUND

The definite treatment of pelvic C fractures presents a widely discussed issue and undergoes continuous evolution. While the stabilization of the posterior ring has been studied extensively, the fixation of the anterior pelvic ring continuous to be rarely investigated. The importance of the simultaneous stabilization however lays in the earlier mobilization and prevention of long-term damage to the pelvis. Therefore we investigated four combinations of minimally invasive fixation techniques for unstable type C1-3 pelvic injuries and aimed to answer the following research questions: (1) what combination of fixation methods yields the highest stiffness and the least displacement? (2) Is the combination of a single sacroiliac screw (SI-screw) with a transiliac internal fixator (TIFI) a reasonable alternative to two SI-screws? (3) Is a modified unilateral anterior fixation comparable to a retrograde transpubic screw?

HYPOTHESIS

Minimally invasive fixation techniques provide sufficient biomechanical stability for type C pelvic fractures.

METHODS

Thirty synthetic full pelvises were divided into 5 groups, of which 4 groups were assigned a different osteosynthesis method and one was an intact pelvis used as reference (group 1: internal fixator+2 sacroiliac screws, group 2: internal fixator+transiliac internal fixator+1 sacroiliac screw, group 3: retrograde transpubic screw+2 sacroiliac screws, group 4: retrograde transpubic screw+transiliac internal fixator+1 sacroiliac screw). The pelvises underwent a protocol of cyclic loading between 100N and 200N, during which they were subjected to compression loads while the position of the fracture fragments was measured every 30 milliseconds. Displacement and stiffness were calculated for statistical analysis.

RESULTS

The minimally invasive fixation methods investigated in this study all provide sufficient biomechanical stability without one method being superior to the others (p [anterior displacement]=0.61 and p [posterior displacement]=0.88). Group 3 was allowed the least displacement (1.8±0.2mm for anterior and posterior fracture) for the treatment of a C1.3 fracture. The other fixation methods displayed the following dislocations (mm) of the anterior pelvic ring: group 1: 1.9±0.3, group 2: 2.1±0.4, group 4: 2.0±0.5. Posteriorly, the displacements (mm) were the following: group 1: 1.8±0.6, group 2: 1.9±0.2, group 4: 2.0±0.5.

DISCUSSION

The minimally invasive fixation methods investigated in this study all provide sufficient biomechanical stability without one method being superior to the others since differences were not significant regarding anterior and posterior displacements. Even if not significantly, we could reveal that out of all the methods tested the combination of 2 SI-screws with a retrograde transpubic screw (group 3) displayed the least displacement and highest stiffness. These techniques could therefore potentially improve patient's clinical outcome by reducing the surgical invasiveness and procedure time while providing sufficient biomechanical stability.

LEVEL OF EVIDENCE

III, comparative in vitro study.

Surgical Treatment for Posterior Dislocation of Hip Combined with Acetabular Fractures Using Preoperative Virtual Simulation and Three-Dimensional Printing Model-Assisted Precontoured Plate Fixation Techniques

Background and Purpose

Hip dislocation combined with acetabular fracture remains a challenging condition for orthopedic surgeons. In this study, we utilized a computer-assisted simulation and three-dimensional (3D) printing technology to treat patients with hip dislocation combined with acetabular fracture. We hypothesized that the 3D printing-assisted method would shorten the internal fixation time and surgical time.

Methods

We retrospectively reviewed 16 patients diagnosed with traumatic posterior dislocation of hip combined with acetabular fractures and treated with plate fixation from September 2013 to August 2017. Patients were divided into two groups: (1) traditional method and (2) 3D printing groups. In the traditional method group, the plates were contoured during the surgery, whereas in the 3D printing group, the patient's pelvic computed tomography image was transformed to the 3D medical image software for processing preoperatively. The fracture reduction was simulated by the computer. Thereafter, the 1:1 scale 3D printing model was used to design the surgical plan and contour patient-specific plates preoperatively.

Results

The internal fixation time was significantly shorter in the 3D printing group than in the traditional method group (-33 min, P<0.05). The mean operative time was shorter than that in the traditional method group (-43 min). However, blood loss and postoperative radiograph results were similar between the groups. The complication rate was lower in the 3D printing group (2/7) than in the traditional method group (5/9).

Interpretation

Computer-assisted simulation with 3D printing technology is a more efficient method for treating hip dislocation combined with acetabular fractures.