Technical Considerations and Fluoroscopy in Percutaneous Fixation of the Pelvis and Acetabulum

Optimizing percutaneous reduction and fixation with guidewire modification in pelvic and acetabular fractures: surgical technique and case series

BACKGROUND

Minimally invasive percutaneous screw fixation for pelvic ring and acetabular fractures has become increasingly popular due to its numerous benefits. However, the precise placement of the screw remains a critical challenge, necessitating a modification of the current techniques. This paper introduces a refined technique employing a modified guidewire to enhance the precision and efficiency of percutaneous fixation in pelvic and acetabular fractures.

METHODS

This study details the surgical techniques implemented for correcting guidewire misdirection in percutaneous screw fixation and includes a retrospective analysis of patients treated with this modified approach over a three-year period.

RESULTS

In this study, 25 patients with pelvic ring and acetabular fractures underwent percutaneous screw fixation. The cohort, predominantly male (23 out of 25), had an average age of 38 years. The majority of injuries were due to traffic accidents (18 out of 25). Types of injuries included pelvic ring (6 cases), acetabular fractures (8 cases), and combined injuries (11 cases). Various screw types, including antegrade and retrograde anterior column screws, retrograde posterior column screws, and lateral compression screws, were used, tailored to each case. Over an average follow-up of 18 months, there were no additional procedures or complications, such as neurovascular injury or hardware failure, indicating successful outcomes in all cases.

CONCLUSIONS

This study introduces a simple yet effective method to address guidewire misdirection during percutaneous fixation for pelvic and acetabular fractures, offering enhanced precision and potentially better patient outcomes. Further research with a larger patient cohort is required for a more comprehensive understanding of its efficacy compared to traditional methods.

LEVEL OF EVIDENCE

IV. Therapeutic Study (Surgical technique and Cases-series).

A feasibility cadaver study for placing screws in various pelvic osseous fracture pathways using a robotic arm

INTRODUCTION

The use of a robotic system for the placement of pedicle screws in spine surgeries is well documented in the literature. However, there is only a single report in the United States describing the use of a robotic system to place two screws in osseous fixation pathways (OFPs) commonly used in the treatment of pelvic and acetabular fractures in a simulated bone model. The purpose of this study was to demonstrate the use of a robotic system to place screws in multiple, clinically relevant OFPs in a cadaveric model and to quantitatively measure accuracy of screw placement relative to the preoperative plan.

METHODS

A single cadaveric specimen was obtained for the purpose of this study. All surrounding soft tissues were left intact. Screws were placed in OFPs, namely iliosacral (IS), trans-sacral (TS), Lateral Compression-II (LC-II), antegrade anterior column (AC) and antegrade posterior column (PC) of the right hemipelvis using standard, fluoroscopically assisted percutaneous or mini-open technique. Following the placement of screws into the right hemipelvis using standard techniques, screws were planned and placed in the same OFPs of the contralateral hemipelvis using the commercially available ExcelsiusGPS® robotic system (Globus Medical Inc., Audubon, PA). After robotic-assisted screw placement, a post-procedure CT scan was obtained to evaluate actual screw placement against the pre-procedure plan. A custom-made image analysis program was devised to measure screw tip/tail offset and angular offset on axial and sagittal planes.

RESULTS

For different OFPs, the mean tip offset, tail offset and angular offsets were 1.6 ± 0.9 mm (Range 0.0-3.6 mm), 1.4 ± 0.4 mm (Range 0.3-2.5 mm) and 1.1 ± 0.4° (Range 0.5-2.1), respectively.

CONCLUSION

In this feasibility study, surgeons were able to place screws into the clinically relevant fracture pathways of the pelvis using ExcelsiusGPS® for robotic-assisted surgery. The measured accuracy was encouraging; however, further investigation is needed to demonstrate that robotic-assisted surgery can be used to successfully place the screws in the bony corridors of the pelvis to treat traumatic pelvic injuries.

Fluroscopy-assisted transiliac antegrade lag screw placement technique in both columns of acetabulum: A novel procedure

The use of pelvic osseous fixation corridors and lag screw fixation in acetabular and pelvic surgery has gained popularity, especially with the recent development of intraoperative imaging and navigation techniques. However, advanced intraoperative imaging and navigation techniques require technical equipment and are costly. Therefore, traditional fluoroscopic techniques still maintain their importance. In this article, we describe a novel pelvic osseous fixation corridor that traverses both columns of the acetabulum, along with the detailed methodology of its fluoroscopic imaging and the techniques for fluoroscopy-assisted screw placement. The technique of placing screws in this current fixation corridor is only under fluoroscopy assistance, without using any specially produced guide or navigation device. LEVEL OF PROOF: IV.

Intraoperative Imaging Challenges During Pelvic Ring Disruptions and Acetabular Fracture Surgery

Achieving high-quality intraoperative imaging is crucial for successful pelvic ring and acetabular fracture surgery, yet it remains clinically challenging. Due to the complex anatomy of the pelvic ring and acetabulum, it is necessary to obtain multiple images oriented in different planes to reliably confirm reduction accuracy and implant positioning. Intraoperative image quality can be compromised by factors such as patient body habitus, bowel gas, abdominal packing, contrast dye, and nonstandardized language between surgeon and radiology technician. This article reviews common intraoperative imaging challenges encountered during pelvic ring and acetabular fracture surgery, while providing practical and evidence-based solutions and prevention strategies.

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.

Union and displacement characteristics following percutaneous screw fixation of superior pubic rami fractures

PURPOSE

To determine union and displacement metrics following percutaneous screw fixation (antegrade or retrograde) of superior pubic rami fractures.

METHODS

This is a retrospective cohort study from a single level 1 trauma center. Skeletally mature patients with at least one superior pubic ramus fracture present as part of a lateral compression-type pelvic ring injury were included.

RESULTS

Eighty-five (85) patients with 95 superior pubic rami fractures met the study's inclusion criteria. LC1, LC2, and LC3 injuries occurred in 76.5%, 15.3%, and 8.2% of patients, respectively. The majority of patients underwent concurrent posterior pelvic ring fixation (94.1%). Superior ramus screw placement occurred predominantly via retrograde technique (81.1%) with cannulated screws of size 6.5 mm or larger (93.7%). Of the 95 eligible fractures, 90 (94.7%) achieved union at a mean of 14.0 weeks (7-40 weeks). Of these united fractures, 69 (76.7%) healed with no measurable displacement, while the remaining 23.3% healed with residual mean displacement of 3.9 mm (range: 0.5-9.0 mm). Multivariable analysis demonstrated a positive association between age (p = 0.04) and initial displacement (p = 0.04) on the final degree of residual displacement at union. A Kaplan-Meier survival analysis identified increased age to be significantly related to increased time to union (X2 (2) = 21.034, p < 0.001).

CONCLUSIONS

Union rates following percutaneous screw fixation of superior pubic rami fractures associated with lateral compression-type pelvic ring injuries approach 95%. Though minimal in an absolute sense, increasing age and a greater degree of initial displacement may influence the final degree of residual displacement at union.

LEVEL OF EVIDENCE

IV.

Percutaneous pelvic fixation model: an affordable and realistic simulator for pelvic trauma training

PURPOSE

To describe the construction and use of a percutaneous pelvic fixation model, evaluate its translational validity among fellowship-trained orthopedic trauma surgeons, and investigate the importance of specific criteria for effective competency-based assessment of pelvic fixation techniques.

METHODS

Five orthopedic trauma surgeons were asked to place percutaneous wires on a pelvic fixation model, including anterior column (antegrade/retrograde), posterior column (antegrade/retrograde), supra-acetabular, transsacral, and iliosacral. Evaluation criteria included successful wire placement, redirections, cortical breaches, procedure duration, radiation exposure, and quality of fluoroscopic views. Following completion, participants were provided a survey to rate the model.

RESULTS

There were no differences between approaches on successful screw placement, wire redirections, or fluoroscopic quality. Antegrade approaches to the anterior and posterior columns took longer (p = 0.008) and used more radiation (p = 0.02). There was also a trend toward more cortical breaches with the antegrade anterior column approach (p = 0.07). Median ratings among surgeons were 4 out of 5 for their overall impression and its accuracy in tactile response, positioning constraints, and fluoroscopic projections. Learning parameters considered most important to the progression of trainees (most to least important) were successful screw placement, corridor breaches, wire redirections, quality of fluoroscopic views, radiation exposure, and procedure duration.

CONCLUSION

In being affordable, accessible, and realistic, this percutaneous pelvic fixation model represents an opportunity to advance orthopedic surgery education globally. Future research is needed to validate the findings of this pilot study and to expand upon how trainees should be evaluated within simulations and the operating room to optimize skill progression.

Evaluation of the effect of pelvis type in percutaneous acetabular column fixation: a computed tomography study

This study aimed to evaluate the effect of pelvis type in percutaneous acetabular column fixation. What is the effect of pelvis type in percutaneous acetabular colon fixation? The available pelvic computed tomography (CT) scans which were obtained in the diagnostic imaging center with a 1 mm slice width were evaluated. The pelvic type was classified with the help of MPR (Multiplanar Reformat) and 3D (Three Dimensional) imaging modes. All evaluated bony pelvic structures were anatomically intact. 40 types of android, gynecoid, anthropoid, and platypelloid pelvis were determined. CT sections were created in MPR imaging mode. Anterior obturator oblique (AOO) and inlet images were created for anterior column evaluation, while iliac oblique (IO) and outlet images were created for posterior column evaluation. The possibility of obtaining a linear corridor for acetabular columns was investigated by measuring corridor width and lengthon images of pelvic CTs. A linear corridor could not be obtained between the pubic tubercle and the supraacetabular region of 12 (30%) CTs in the anterior column of gynecoid pelvis group. The diameter of the anterior column corridor was below 5.5 mm in 10 (25%) of Gynecoid pelvis group, 5 (12.5%) of Anthropoid pelvis group, and 10 of Platypelloid pelvis group, , and all those scans belonged to the female gender. There was a statistically significant difference between pelvis types in terms of anterior and posterior column diameters (p <0.001). While the android pelvis type had the highest diameter and corridor length in both anterior column and posterior column measurements, the gynecoid pelvic type had the lowest diameter and corridor length. In the evaluations made according to gender, both anterior and posterior column diameters were larger and longer in males than in females (p <0.001). Pelvis type is an important factor which can affect anterior and posterior column diameter and length of acetabulum. Pelvic typing before acetabular surgery can help the surgeon determining the most appropriate patient position, surgical approach, and implant selection. Level of Evidence: Level 2.

Comparison of 3D Bone Position Estimation Using QR Code and Metal Bead Markers

To improve the accuracy of a 3D bone position estimation system that displays 3D images in response to changes in the position of fluoroscopic images, modified markers using quick response (QR) codes were developed. The aims of this study were to assess the accuracy of the estimated bone position on 3D images with reference to QR code markers on fluoroscopic images and to compare its accuracy with metal bead markers. Bone positions were estimated from reference points on a fluoroscopic image compared with those on a 3D image. The positional relationships of QR code and metal bead markers on the fluoroscopic image were compared with those on the 3D image in order to establish whether a 3D image may be drawn by tracking positional changes in radius models. Differences were investigated by comparing the distance between markers on the fluoroscopic image and that on the 3D image, which was projected on the monitor. The error ratio, which was defined as the difference in the measurement between the fluoroscopic and 3D images divided by the fluoroscopic measurement, was compared between QR code and metal bead markers. Error ratios for the QR code markers were 5.0 ± 2.0%, 6.4 ± 7.6%, and 1.0 ± 0.8% in the anterior–posterior view, ulnar side lateral view, and posterior–anterior view, respectively. Error ratios for the metal bead markers were 1.3 ± 1.7%, 13.8 ± 14.5%, and 4.7 ± 5.7% in the anterior–posterior view, ulnar side lateral view, and posterior–anterior view, respectively. The error ratio for the metal bead markers was smaller in the initial position (p < 0.01). However, the error ratios for the QR code markers were smaller in the lateral position and the posterior–anterior position (p < 0.05). In QR code marker tracking, tracking was successful even with discontinuous images. The accuracy of a 3D bone position estimation was increased by using the QR code marker system. QR code marker tracking facilitates real-time comparisons of dynamic changes in preoperative 3D and intraoperative fluoroscopic images.

[Imaging examination procedures, navigation and minimally invasive procedures in acetabular surgery]

Acetabular fractures still pose a special challenge even today. Considering the increasing case numbers, especially in the geriatric patient group, modern imaging examination procedures represent an essential pillar of the diagnostics. Especially in this vulnerable patient group, minimally invasive methods are necessary, which can be guaranteed by intraoperative navigation; however, the choice of surgical access and implants is also made based on the existing morphological characteristics of fractures, which highlights the importance of an imaging modality that is as detailed as possible. Last but not least, new developments concerning the surgical treatment of these injuries are also based on this. This article summarizes the current state of the techniques and the available literature.

What are the optimal targeting visualizations for performing surgical navigation of iliosacral screws? A user study

INTRODUCTION

Complex orthopaedic procedures, such as iliosacral screw (ISS) fixations, can take advantage of surgical navigation technology to achieve accurate results. Although the impact of surgical navigation on outcomes has been studied, no studies to date have quantified how the design of the targeting display used for navigation affects ISS targeting performance. However, it is known in other contexts that how task information is displayed can have significant effects on both accuracy and time required to perform motor tasks, and that this can be different among users with different experience levels. This study aimed to investigate which visualization techniques helped experienced surgeons and inexperienced users most efficiently and accurately align a surgical tool to a target axis.

METHODS

We recruited 21 participants and conducted a user study to investigate five proposed 2D visualizations (bullseye, rotated bullseye, target-fixed, tool-fixed in translation, and tool-fixed in translation and rotation) with varying representations of the ISS targets and tool, and one 3D visualization. We measured the targeting accuracy achieved by each participant, as well as the time required to perform the task using each of the visualizations.

RESULTS

We found that all 2D visualizations had equivalent translational and rotational errors, with mean translational errors below 0.9 mm and rotational errors below 1.1[Formula: see text]. The 3D visualization had statistically greater mean translational and rotational errors (4.29 mm and 5.47[Formula: see text], p < 0.001) across all users. We also found that the 2D bullseye view allowed users to complete the simulated task most efficiently (mean 30.2 s; 95% CI 26.4-35.7 s), even when combined with other visualizations.

CONCLUSIONS

Our results show that 2D bullseye views helped both experienced orthopaedic trauma surgeons and inexperienced users target iliosacral screws accurately and efficiently. These findings could inform the design of visualizations for use in a surgical navigation system for screw insertions for both training and surgical practice.

Sacroiliac screws fixation navigated with three-dimensional printing personalized guide template for the treatment of posterior pelvic ring injury: A case report

Objective

Pelvic injuries refer to the disruption of the inherent structural and mechanical integrity of the pelvic ring. Sacroiliac screw fixation technique is often used for the treatment of posterior pelvic ring injury, which is prone to the iatrogenic injury. Various attempts were proposed to avoid iatrogenic injuries, while the executing processes are usually too cumbersome. The patient-personalized guide template based on 3D printing technology has been considered as a promising method, which can achieve lower deviation and higher accuracy in a simple and convenient way. We reported the first case of posterior pelvic ring injury using 3D printing personalized guide template with the verification of intraoperative CT.

Methods

The subject was a 74-year-old female with posterior pelvic ring injury. Two patient-specific guide templates were customized based on 3D printing technology, one for S1 and the other for S2. We used the guide templates for navigation to place the sacroiliac screws. The placement of screws was verified by intraoperative CT. Intraoperative and postoperative variables were collected.

Results

The technique helped us successfully insert the sacroiliac screws into the safe zone. The intraoperative blood loss was 23.03 ml, and the duration of operation was 62 min. The exposure dose during CT scanning was 7.025 mSv. The assessment of screws position was excellent. Furthermore, there was no sign of any functional impairment postoperatively.

Conclusion

Sacroiliac screws fixation with the assistance of 3D printing personalized guide template under the verification of intraoperative CT may be a promising method to treat posterior pelvic ring injuries.

Robot-assisted versus conventional percutaneous sacroiliac screw fixation for posterior pelvic ring injuries: a systematic review and meta-analysis

PURPOSE

Robot-assisted pelvic screw fixation is a new technology with promising benefits on intraoperative outcomes for patients with posterior pelvic ring injuries. We aim to compare robot-assisted pelvic screw fixation to the traditional fluoroscopy-assisted technique with regards to intraoperative and postoperative outcomes.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used along with a search of electronic information to identify all studies comparing the outcomes of robot-assisted versus conventional screw fixation in patients with posterior pelvic ring injuries. Primary outcomes included operative duration (minutes), intraoperative bleeding (mL), fluoroscopy exposure and intraoperative drilling frequency. Secondary outcome measures included Majeed score, healing time (minutes) and rate (%), postoperative complications, screw positioning, incision length (cm) and guide wire insertion times (minutes). The random effects model was used for analysis.

RESULTS

Four observational studies including a total of 294 patients were identified. There was a significant difference between robot-assisted and conventional groups in terms of operative duration (MD = - 24.66, p < 0.05), intraoperative bleeding (MD = - 10.37, P < 0.05), fluoroscopy exposure (MD = - 2.15, P < 0.05) and intraoperative drilling frequency (MD = - 2.42, P =  < 0.05). For secondary outcomes, no significant difference was seen in Majeed score, healing time and rate and postoperative complications. The robot-assisted group had better screw positioning, smaller incision length, and shorter anaesthesia and guide wire insertion times.

CONCLUSIONS

Robot-assisted fixation has superior intraoperative outcomes compared to conventional fixation. Further studies are needed to look at postoperative outcomes as there is no significant difference in postoperative prognosis between the techniques.

Imaging, post-processing and navigation: Surgical applications in pelvic fracture treatment

Technical advancements of the past decade have led to massive improvements regarding imaging and visualization in trauma care. Digital imaging technology has fundamentally changed most processes in fracture management. However, the digital revolution in trauma surgery has just begun. Optical tracking navigation is currently the gold standard for positioning of implants for advanced applications in trauma surgery. Digital technology may enable the surgeon to achieve the same level of safety even in non-navigated placement of screws: We developed a new planning tool to transcript a preoperative into a semi-transparent "fluoroscopic like" image that can be identified intraoperatively and used as a map for the safe placement of sacro-iliac screws based on the "vestibule concept". In the future, development of artificial intelligence algorithms may provide features like automated segmentation of bone-fragments and other applications for a systematic fracture analysis to improve the standard of care in trauma surgery. Digital transformation has massive impact on diagnostics and surgical management of pelvic fractures. Improved visualization technology provides a better understanding of the surgical anatomy of the pelvis and may enable the surgeon to achieve greatest safety in percutaneous placement of screws even without using optical tracking navigation tools. The "para-axial fusion technique" is a useful tool to plan fluoroscopic views based on a 3D dataset prior to the surgery.

Identifying safe corridors for anterior pelvic percutaneous instrumentation using computed tomography-based anatomical relationships

INTRODUCTION

Percutaneous anterior pelvic ring instrumentation is performed for retrograde screw fixation of ramus fractures, as well as for repair of pubic symphysis diastasis. The anatomic relationships of critical structures around the anterior pelvic ring, such as the spermatic cord and round ligament, have been described in only a few studies regarding the risk of iatrogenic injury during surgery. Our goal is to further describe these relationships, as well as provide radiographic information on safe corridors for percutaneous fixation.

METHODS

Eighty (80) axial computed tomography scans of the abdomen, obtained for non traumatic diagnostic purposes and screened for prior abdominal trauma or procedures, were evaluated by 3 fellowship trained radiologists. Mid-symphyseal cuts were used to obtain several measurements relative to the spermatic cords (SC) or round ligaments (RL): inter-cord or inter-ligament distance, skin to cortex of symphysis distance (vertical), skin to cortex of symphysis distance (oblique), safe corridor distance (between SC/RL and femoral triangle), center safe angle (relative to bilateral ischia), maximal safe angle, and minimal safe angle.

RESULTS

There were 41 male and 39 female scans included in the final analysis. The average inter-cord distance was 50.2 mm, skin to cortex vertical distance of 43.0 mm, skin to cortex oblique distance of 83.5 mm, safe corridor distance 26.3 mm, center safe angle 19.3˚, maximal safe angle 32.3˚, and minimal safe angle 13.6˚. These were further broken down by range and gender in Table 1. Agreement between radiologists was high for these different measurements with the exception of the skin to cortex oblique distance in female patients and the maximal safe angle in female patients, due to absence of round ligament in a majority of the scans. The round ligament was only present at the mid-symphyseal level for our three reviewers in 37/39, 36/39, and 24/39 of female patient scans.

CONCLUSIONS

We have identified defined safe corridors for instrumentation of the anterior pelvic ring that can assist the surgeon in percutaneous application of fixation for fracture care.

Placement of LC-II and trans-sacral screws using a robotic arm in a simulated bone model in the supine position - a feasibility study

Purpose

The use of a robotic arm has been well-described in the literature for the placement of pedicle screws in spine surgery as well as implants for sacroiliac joint fusion. There are no reports describing the use of a robotic arm to place screws in osseous fixation pathways (OFPs) employed in the treatment of pelvic ring and acetabular fractures outside of a single center in China. Using a Sawbones model, the authors describe a technique for using a robotic arm widely available in Europe and the Americas for placement of 6.5 mm cannulated screws into two OFPs commonly used in the treatment of pelvic and acetabular fractures.

Methods

Using the Mazor X Stealth Edition (MSXE) robot from Medtronic, the authors were able to place a pin into the pelvis onto which the robot was docked. The authors were then able to designate the area of interest using navigated instruments, and in combination with the MSXE “scan and plan” marker, obtain cross-sectional imaging using the O-Arm and successfully register the MSXE robot. We then used the provided software to plan trajectories for the lateral compression type 2 (LC-II) screw pathway as well as a pathway for a trans-ilio-trans-sacral screw. We describe in detail the steps for setup, planning and placement of 6.5 mm cannulated screws using the MSXE robotic arm into these two OFPs.

Results

Visual inspection and plain x-rays demonstrated successful placement of the screws into the two planned OFPs. No breach of cortical bone was seen on either visual inspection of the model or demonstrated on post-procedure x-rays.

Conclusion

It is possible to use the Mazor X Stealth Edition robot to place screws into the LC-II and trans-ilio-transsacral screw pathways in a Sawbones model. This is only a feasibility study, and should in no way be taken to suggest that clinical application of this technique should be attempted.

The survivorship and factors affecting the outcome of the use of spring plates in multifragmentary posterior wall acetabular fractures at a single academic institution

BACKGROUND

Multifragmentary posterior wall fractures are not uncommon after posterior hip fracture-dislocation. They can be elementary but are commonly associated with transverse acetabular fractures. Specific technical challenges are encountered when managing these fracture patterns. The loss of the posterior landmarks due to the associated comminution may render achieving an anatomical reduction and stable fixation difficult. The application of spring plates can provide a good buttress with multiple anchor points and creates a new cortex for the bridging plate.

PURPOSE OF THE STUDY

-To assess the outcome and survivorship of the use of spring plates for the fixation of multi-fragmentary posterior wall fractures. -To analyse the factors affecting the outcome of the fixation of these challenging injuries.

PATIENTS AND METHODS

We retrospectively reviewed all the patients who underwent posterior wall acetabular fixation using a spring plate between December 2009 and March 2020 at our institution. Forty-seven patients had a minimum follow-up of 1 year and were included in the study with a mean age of 36 ± 10 years (range:17-60) and a mean follow-up period of 4.4 ± 3.5 years. Seventeen patients had an associated transverse acetabular fracture, and an anterior columnar screw was used for additional fixation. Functional outcome was assessed using the Oxford hip score (OHS). Radiological assessment was undertaken for the images done immediately post-operatively and at the last follow-up. Patients with advanced post-traumatic arthritis and complications such as avascular necrosis (AVN), nerve injuries, non-union, heterotopic ossification and fixation failure were identified. The hazard rate of re-operation on the native hip was estimated using the life tables. Kaplan Meier analysis was used to assess survival with THR or excision arthroplasty as an endpoint.

RESULTS

Six patients underwent a total hip replacement: secondary to AVN in four and infection in two patients. The hazard of THR was estimated at 6% (SE = 0.02) during the first three years, then decreased dramatically afterwards. The five-year survival of native hip was 83% (SE = 0.06). Native hip was expected to survive for 10.67 years (95% CI 9.49-11.83) without joint replacement. The mean OHS in our cohort was 33.66 (3-48), and 29 patients (61.70%) had an OHS of more than 30.

CONCLUSION

The use of spring plates to fix multifragmentary posterior wall fractures has excellent mid-term results, high survivorship and a low complication rate. Combining an anterior columnar screw and a posterior spring plate has shown to be a suitable fixation construct in selected patients with associated transverse acetabular fractures. A longer-term follow-up with a larger cohort using this fixation construct is needed.

Is unrestricted weight bearing immediately after fixation of rotationally unstable pelvic fractures safe?

INTRODUCTION

Rotationally unstable pelvic fractures treated with surgical fixation have traditionally been treated with restricted weight bearing on the affected side for 6-8 weeks post operatively. We have been developing pelvic fixation standards to allow for unrestricted weight bearing immediately post operatively in type B rotationally unstable pelvic fractures.

AIMS

To assess for safety and efficacy of allowing unrestrictive weight bearing in this cohort of patients, we have clinically and radiologically monitored outcomes up to two years post operatively.

METHODS

Through retrospective review, two cohorts of patients with Tile Type B pelvic fractures were identified that were treated at the Royal Adelaide Hospital, South Australia. Patient demographics, injury classification, surgical fixation and weight bearing status post operatively was recorded. One cohort of patients was allowed to fully weight bear post operatively, whilst the other was treated with 6 weeks of restricted post op weight bearing. At clinical follow up, post-operative x-rays were assessed for loss of reduction, screw or plate breakage and reoperation.

RESULTS

Between January 2018 and January 2021, 53 patients with rotationally unstable pelvic fractures that underwent surgical fixation were included in this study. One group of patents were allowed to immediately weight bear as tolerated (WBAT) post operatively (n = 28) and the other with restricted weightbearing (RWB) (n = 25). There was 1 re operation for failure of fixation in each group. Metalwork breakage was more common in the WBAT group than in the RWB group and this was seen only in APC fractures. This increase in metalwork failure was not associated with loss of reduction.

CONCLUSIONS

With surgical fixation, Tile type B rotationally unstable pelvic fractures can be allowed immediate weight bearing post operatively. We found this to be safe and effective, employing surgical strategies to address both anterior and posterior injuries to allow immediate unrestricted weight bearing. Broken metalwork was more commonly seen in the WBAT group but this was not associated with loss of reduction or reoperation.

An anatomical study defining the safe range of angles in percutaneous iliosacral and transsacral screw fixation

Percutaneous iliosacral screw fixation and transsacral fixation are challenging procedures requiring extensive knowledge of sacral anatomy to avoid damaging nearby neurovascular structures. Greater knowledge of anatomical screw trajectory and size allowances would be helpful to guide surgical placement. An anatomical study of 40 cadaveric sacra in specimens ages 18-65 was performed. Three-dimensional surface scans were obtained, and computer modeling software was used to simulate a 7.3 mm diameter screw with 1 mm buffer inserted orthogonal to the sacroiliac joint in the pelvic inlet and outlet views. Transsacral screws were also inserted into S1 and S2 vertebrae. For screws orthogonal to the sacroiliac joint, the overall mean screw insertion angle was 4.1° ± 7.5° (range, -18.3° to 22.0°) in the inlet view in the posterior to anterior direction, and 21.7° ± 5.1° (range, 8.2°-36.3°) in the outlet view in the caudal to cranial direction. Before breaching the sacrum, the range of sacral tunnel lengths was between 31.1 and 70.1 mm with a range of diameters between 9.3 and 13.3 mm. Transsacral screws inserted into either the S1 or S2 vertebrae did not breach the sacrum in 40% (16/40) at each level. 30% (12/40) of sacra could not safely accommodate both S1 and S2 transsacral screws. There is an initial screw insertion angle range of -4° to 12° in the inlet view and 16°-27° in the outlet view. There was always adequate size to accept a 7.3 mm or larger screw.

Anatomical Considerations in Percutaneous Fixation of the Pelvis and Acetabulum

Reduction and fixation techniques of the pelvis and acetabulum continue to evolve. There has been increased use of percutaneous and minimally invasive techniques in the past several decades. Although offering many advantages to traditional open techniques, percutaneous techniques still place nearby structures at risk, making a thorough understanding of the applied surgical anatomy essential.

Obturator Oblique and Pubic Ramus Inlet Views Can Better Guide the Insertion of an Anterior Column Acetabular Screw

OBJECTIVE

The objective of the present paper was to investigate the value of obturator oblique and pubic ramus inlet views in guiding anterior column acetabular screw insertion.

METHODS

We collected pelvic CT scans at the diagnostic imaging center of our hospital between 2017 and 2019. Virtual three-dimensional (3D) models of the pelvis were created based on the CT scans. Then the transparency was adjusted to 30%. Two identical copies of the 3D model data were made. 3D model replications were divided into a control group and an experimental group. In the control group, the screw was inserted into the anterior acetabular column using obturator-outlet and iliac-inlet views. In the experimental group, the screw was guided under obturator oblique and pubic ramus inlet views. Based on whether the screw penetrated the hip joint and/or exited the pubic ramus, models were divided into three grades. Grade I: the screw travels completely within the anterior column bone corridor; Grade II: the screw exits the superior pubic ramus, but the length of the screw outside the channel does not exceed 1/2 of the anterior column; Grade III: the screw exits the superior pubic ramus and the length of the screw outside the corridor exceeds 1/2 of the anterior column. We compared the screw placement quality of the two groups and analyzed differences between genders. In addition, the distance between the screws and the acetabulum was recorded and compared among the two groups.

RESULTS

A total of 110 hemipelves were selected, including those of 80 men and 30 women, with an average age of 46.76 ± 14.26 years. In the control group, the screw quality of 64 models (58.2%) was Grade I. In the experimental group, 94 models (85.5%) had Grade I screw placement quality. Grade II screw placement quality accounted for 18.2% of the control group and 7.3% of the experimental group. In the control and the experimental groups, there were 26 and 8 cases with Grade III screw placement quality, respectively. The quality of screw placement in the experimental group was significantly better than that in control group, and the difference between the two groups was statistically significant (P < 0.01). The distance between the screw and the acetabulum in the control group and experimental group was 0.92 ± 0.49 mm and 2.78 ± 1.15 mm, respectively. The difference between the two groups was statistically significant.

CONCLUSION

Anterior column acetabular screws can be inserted successfully and more accurately using the obturator oblique and pubic ramus inlet views.

Clinical outcomes in prone positioning for percutaneous fixation of posterior column acetabular fractures

PURPOSE

Percutaneous retrograde fixation of posterior column acetabular fractures is becoming a commonly practiced technique. Prone positioning provides reliably reproducible intraoperative fluoroscopic images necessary for precise preparation of the osseous fixation corridor necessary for accurate and safe implant placement. Additionally, the prone position facilitates an open posterior approach if an open reduction is necessary. The purpose of this study was to analyze the radiographic and clinical outcomes of retrograde posterior column fixation utilizing the prone position.

METHODS

From 2017 to 2020, 41 patients were included in the retrospective study. Clinical outcomes were collected for a minimum of 6 months. Implant placement was assessed on post-operative pelvic computed tomography (CT) scans and fracture union was assessed on routine follow-up radiographs.

RESULTS

All (100%) cases achieved union by 4 months, with an average time to union of 3.2 months. Every post-operative CT scan demonstrated screw placement contained throughout the posterior column with no intrusion into the hip joint or sciatic notch. Clinically, one patient reported pain with sitting. No patients required additional surgical intervention.

CONCLUSION

Prone positioning is a versatile and effective approach for retrograde percutaneous fixation of posterior column acetabular fractures. This study is the first to report clinical outcomes utilizing this technique and contributes to a growing body of the literature supporting the value and safety of percutaneous fixation of acetabular fractures appropriate for this fixation strategy.

A graphic guide to the percutaneous tripod acetabular reconstruction for metastatic cancer

Symptomatic peri-acetabular metastatic lesions are often treated with open surgery such as modified Harrington procedures. In an effort to avoid surgical complications inherently associated with open surgical approaches, we developed and recently reported a novel Tripod percutaneous screw technique. The tripod technique is minimally invasive and was found to yield excellent outcomes regarding both pain control and functionality. The procedure is performed in a standard operative theater using fluoroscopic guided percutaneous screws. Despite the simplicity of intraoperative set-up and instrumentation, it is technically demanding. Obtaining the correct fluoroscopic views and troubleshooting intraoperative hurdles can be challenging for even an experienced orthopedic surgeon. The technique and bony conduits were previously described in the trauma literature, however, there are key points of difference in the setting of metastatic disease. Here we provide a compilation of a stepwise graphic guide for the tripod model in the setting of metastatic peri-acetabular lesions, as well as the tips and tricks based on our own experience. These encompass preoperative preparation, operating room settings, intraoperative fluoroscopic guidance, postoperative care, and subsequent conversion to a cemented total hip arthroplasty, if needed.

The first use of laparoscopy to treat pelvic ring fractures: A case report

•

The first use of laparoscopy to treat pelvic ring fractures: a case report.

•

We describe the first use of laparoscopy to treat pelvic ring fracture.

•

This “laparoscopic internal fixation” delivered an in situ result as good as that of open surgery.

•

Despite a long operating time, the blood loss was very low.

•

This technique opens a new approach to treatment of pelvic fractures.

Introduction

Pelvic ring injuries pose major challenges for the trauma surgeon. Given the complications of open surgeries, percutaneous techniques have become increasingly popular, but laparoscopy has never been employed for internal osteosynthesis of the pelvic ring.

Presentation of case

We describe a 34-year-old male with a pelvic ring fracture (grade AO/OTA 61B2.1b). The anterior pelvic arch was successfully plate-fixed using a laparoscopic technique. This is the first report of such an approach to treat pelvic ring fractures.

Discussion

Our principal point is that “laparoscopic internal fixation” delivered an in situ result as good as that of open surgery, but we required only four trocar portals.

Conclusion

We describe a novel laparoscopic approach to treatment of pelvic ring fractures.