Quality of reduction correlates with clinical outcome in pelvic ring fractures

A comparison of anterior ring fixation constructs in Young-Burgess lateral compression type 2 and 3 (LC2, LC3; AO/OTA 61-B2/B3) pelvic ring injuries: does fixation matter?

OBJECTIVE

To compare outcomes of lateral compression LC2 and LC3 pelvic ring injuries when posterior ring fixation is applied and different anterior ring constructs are used.

METHODS

A retrospective analysis from two Academic Level I Trauma Centers of all operatively treated LC2 and LC3 (AO/OTA 61-B2/B3) pelvic ring injuries from January 2019-January 2024. A comparison of anterior ring constructs was made: no fixation vs. fixation; indirect fixation (external fixators and InFix)) vs. internal fixation; long vs. short percutaneous screws. Long percutaneous screws were defined as either bicortical bypassing all 3 Nakatani zones or bypassing the fracture by 2 Nakatani zones with intramedullary juxtacortical or bicortical finishing. A short screw was defined as all other screws, regardless of direction. Primary outcome measure was >1 cm of pelvic ring displacement from post-operative to final radiographs showing fracture healing with sufficient callus. Secondary outcomes were unplanned major reoperation, removal of implants or non-union repair, and other surgical complications.

RESULTS

67 patients met inclusion criteria. Most were female (n = 35, 52 %), mean age was 48.3 (SD 21.7) and most injuries were LC3 (n = 39, 58 %). All cases had posterior ring fixation. Twelve (18 %) had no anterior ring fixation and there was a statistically higher rate of deformity compared with patients with anterior ring fixation (n = 55, 82 %) (58 % vs. 16 %, p = 0.005). Indirect fixation (n = 12, 18 %) had a statistically higher rate of deformity compared with internal fixation (n = 43, 64 %) (50 % vs. 7 %, p = 0.002). There was a statistically higher rate of deformity when a short percutaneous screw (n = 6, 9 %) rather than long screw was used (n = 26, 39 %) (50 % vs. 0 %, p = 0.004).

CONCLUSIONS

Routine anterior ring fixation in conjunction with posterior ring fixation is strongly encouraged for LC2 and LC3 injuries. A long percutaneously-applied anterior screw provides optimal stability to maintain reduction and prevent deformity.

LEVEL OF EVIDENCE

Therapeutic Level 3.

Preoperative 3D printing planning technology combined with orthopedic surgical robot-assisted minimally invasive screw fixation for the treatment of pelvic fractures: a retrospective study

Objective

To explore the advantages and effectiveness of preoperative 3D printing planning technology combined with orthopedic surgical robot-assisted screw placement in the minimally invasive treatment of pelvic fractures compared to orthopedic surgical robot-assisted screw placement alone.

Methods

A retrospective analysis of the clinical data of 29 patients with unstable pelvic fractures treated with orthopedic surgical robot-assisted percutaneous screw fixation from July 2021 to August 2023 was conducted. Among them, 13 patients who underwent preoperative 3D printing technology for screw planning were assigned to the experimental group, and the remaining 16 patients were assigned to the control group. All patients underwent screw fixation alone or combined with other fixation methods for fracture fixation. The application of preoperative 3D printing planning in orthopedic surgical robot operations was described. The intraoperative screw drawing time, invasive operation time, number of fluoroscopies during invasive operation, postoperative evaluation of screw accuracy, fracture healing, complications, and functional outcomes were recorded and compared between the two groups.

Results

All patients successfully underwent surgery, with one patient in the control group experiencing numbness in the sciatic nerve innervation area. All patients were followed up for 4-15 months, with an average of 8 months, and all fractures achieved healing. The experimental group had a total of 26 screws inserted, while the control group had 30 screws. In the experimental group, the intraoperative screw drawing time was 3.0 (3.0, 3.37) min, significantly shorter than 4.0 (3.6, 4.0) min in the control group (P < 0.05). The proportion of screws not penetrating the bone postoperatively was 88.5% in the experimental group, significantly higher than 63.3% in the control group (P < 0.05). In the experimental group, the postoperative screw position, compared to the planned screw position, had an average position deviation of 3.05 ± 0.673 mm and an average spatial angle deviation of 2.22 ± 0.605°. At the last follow-up, the Majeed score was used to assess function, with the experimental group having an excellent and good rate of 84.6%, slightly higher than 75.0% in the control group, but the difference was not statistically significant (P > 0.05).

Conclusion

In the treatment of pelvic fractures using screw fixation, preoperative 3D printing technology planning combined with orthopedic surgical robots, compared to orthopedic surgical robot-assisted screw placement alone, can significantly reduce intraoperative screw drawing time, decrease drawing difficulty, enhance screw placement accuracy, and does not increase invasive operation time or the number of fluoroscopies. This approach makes the surgery safer and is a method worth applying.

Is patient-reported outcome after treatment of unstable pelvic ring injuries related to pelvic symmetry? A prospective study

PURPOSE

To determine the relation between pelvic symmetry, as measured by the cross-measurement technique, and patient-reported outcome measures (PROMs) in terms of functional status and health-related quality of life.

METHODS

In this prospective cohort study, X and Y measurements were taken according to the cross-measurement technique on AP radiographs of patients who were treated for an unstable pelvic ring injury in a level-1 trauma center. Patients completed PROMs at the time of admission (recalled pre-injury score) and one year following their injury, reporting their functional status with the Short Musculoskeletal Function Assessment (SMFA-NL), specifically the lower extremity dysfunction (LED), problems with daily activities (PDA) and mental and emotional problems (MEP) subscales, and quality of life with EuroQol-5D (EQ-5D). Subgroup analyses were also performed. PROMs were used to analyze the relation between pelvic symmetry and patient-reported outcome, using Spearman's Rank correlation coefficients.

RESULTS

A total of 130 patients (mean age 58 (SD18) years) with an unstable pelvic ring injury were included, of which 95 (73%) sustained type-B injuries and 35 (27%) type-C injuries. Sixty-three (49%) patients were treated operatively. The median pelvic symmetry ratio was 1.01 (IQR: 0.05). Weak or no correlations were found between the pelvic symmetry scores and the outcome measurements (Spearman's correlation coefficients: LED r = 0.09; PDA r = 0.11; MEP r=-0.02; and EQ-5D r=-0.08). Subgroup analyses revealed no correlations.

CONCLUSIONS

No significant relation was found between pelvic symmetry, measured radiologically, and functional status and health-related quality of life, one year following an unstable pelvic ring injury.

Modified screw-rod fixation for management of posterior pelvic ring fractures: a retrospective study

BACKGROUND

Pelvic fractures are often associated with life-threatening damage and mechanical instability. Surgical therapy is a prior choice. To minimize surgical invasion and risk, bilateral screws combined with curved rod were applied to stabilize posterior pelvic ring. This study was aim to explore the clinical effect of this procedure.

METHODS

From January 2018 to January 2022, 27 patients with posterior pelvic fracture were included retrospectively. There were 12 males and 15 females with an average age of 56.3 ± 14.2 years. The prognosis of pelvis was evaluated by Matta and Majeed scores. Relevant clinical evaluation indications include the time of fracture healing, limb function and complications.

RESULTS

The average follow-up time was 14.2 ± 5.4 month. Matta scoring standard: excellent in 18 cases, good in 7 cases, the good rate was 92.6%. The average healing time was 8.4 months. The standard of Majeed score in 6 months after operation: excellent in 14 cases, good in 10 cases, the good rate was 88.8%. At the last follow-up, the functional recovery of the affected limb was satisfactory. No deep infection occurred after operation. The neurological symptoms of patients with caudal sacral nerve injury were recovered 6 months after operation.

CONCLUSION

The results indicated that screw-rod system is a safe technique. Minimally invasive technology reduced frequency of fluoroscopy. It provides a simple and safety method for posterior pelvic fracture.

Comparison of the MIPPO technique and the modified Stoppa approach in the treatment of unstable anterior pelvic ring injuries: a retrospective cohort study

BACKGROUND

Anterior pelvic ring injuries have gradually become common. Using a minimally invasive technique to treat this injury may be feasible if the reduction and stability can be effectively achieved. We describe a percutaneous technique, minimally invasive percutaneous plate osteosynthesis (MIPPO), to fixate the anterior pelvis via establishing a subperiosteal tunnel between two limited incisions over the iliac crest(s) and pubic ramus in this research.

METHODS

A retrospective cohort study comparing the MIPPO technique (n = 60) versus the modified Stoppa approach (n = 53) for anterior pelvic ring injuries with posterior ring instability was performed from September 2016 to January 2023. The relative surgery variables, follow-up function evaluation, and complications were compared in two groups. The reduction quality of fracture was assessed according to the Matta criterion, and the functional score was evaluated using the Majeed score.

RESULTS

All patients completed follow-up, with an average interval of 39.90 ± 17.53 months (range 12-78). In the MIPPO technique group, the surgery interval and blood losses were lower compared to the modified Stoppa approach group (P<0.05). The mean procedure times and intraoperative blood losses were 69.56 ± 14.04 min/side (range 50-110) and 156.23 ± 49.75 mL/side (range 90-250) for unilateral anterior ring MIPPO fixation separately. All patients got a satisfactory reduction of the fracture. In the follow-up, earlier ambulation, shorter postoperative hospital stays, and lower complication rates were observed for patients using the MIPPO technique compared to the modified Stoppa approach (P<0.05). However, there is no statistical difference in these indicators including fracture union interval, full load time, the Majeed score, patient satisfaction level, and return to pre-injured work rate between the two groups.

CONCLUSION

This clinical experience gives support for the use of the MIPPO technique to stabilize the anterior pelvis. This minimally invasive technique was an effective and safe surgery method and could obtain satisfactory function results, particularly fitting to part of patients with resistance using the modified Stoppa approach.

Oblique anterior pelvic external fixator for intraoperative reduction of rotationally unstable pelvic ring injuries

Incomplete sacroiliac joint injuries are often associated with external rotation and extension deformities on the injured hemipelvis. To appropriately correct this deformity, an oblique reduction force from caudal to cranial and lateral to medial is helpful. These injuries are often associated with traumatic disruption of the pubic symphysis. However, in injuries without traumatic disruption to the pubic symphysis, a two-pin oblique anterior external fixator can be used to obtain and maintain reduction of the sacroiliac joint, while percutaneous fixation is subsequently placed. Through a small case series and three specific patient examples, we demonstrate that the oblique anterior external fixator frame is a simple and effective strategy with the reduction and stabilization process of these multiplanar hemipelvis deformities.

Intelligent robot-assisted fracture reduction system for the treatment of unstable pelvic fractures

BACKGROUND

Precise and minimally invasive closed reduction is the premise of minimally invasive internal fixation. This paper aims to explore the safety and efficacy of a robot-assisted fracture reduction system (RAFR) in the treatment of pelvic fractures and to analyze its clinical advantages and existing problems.

METHODS

The RAFR system intelligently designed the optimal reduction path and target position based on a preoperative three-dimensional(3D) CT scan of the patient. The reduction robotic arm automatically reduced the affected hemipelvis according to the pre-planned reduction path.

RESULTS

The average residual displacement was the 6.65 ± 3.59 mm. According to Matta's criteria, there were 7 excellent, 10 good, and 3 fair, and the excellent and good rate was 85%. No postoperative complications occurred.

CONCLUSION

In our study, the RAFR system could complete accurate and minimally invasive closed reduction for most patients with unstable pelvic fractures, which could achieve good fracture reduction quality and short-term efficacy.

Critical distance of the sacroiliac joint for open reduction using screw fixation for traumatic sacroiliac joint diastasis: a retrospective study

BACKGROUND

Osteosynthesis for sacroiliac joint (SIJ) diastasis using an iliosacral screw (ISS) and a trans-iliac-trans-sacral screw (TITSS) can be performed using a closed or an open method. However, no clear indication for open reduction has been established.

METHODS

Data on patients with unilateral traumatic SIJ diastasis who underwent ISS and TITSS fixation were retrospectively collected and separated into groups according to the reduction method: closed reduction group (C group) and open reduction group (O group). Demographic data and perioperative image assessments were compared between the groups. The critical distance of the SIJ was identified to elucidate the indication for open reduction of the diastatic SIJ.

RESULTS

Fifty-six patients met the inclusion criteria over a 3-year period. There was no significant difference in the reduction quality of pelvic ring injuries between the groups, according to Matta's and Lefaivre's criteria. The improvement in the SIJ distance was significantly greater in the O group than in the C group in the axial plane on multiplanar computed tomography (p = 0.021). This model predicted that a difference of > 3.71 mm between the injured and healthy SIJ was a recommended indication for open reduction, with an area under the curve of 0.791 (95% confidence interval 0.627-0.955, p = 0.004).

CONCLUSIONS

Open reduction for SIJ diastasis might achieve better reduction quality than does closed reduction in the axial plane in selected cases. When the difference between the injured and healthy SIJ was wider than 3.71 mm, open reduction was recommended for satisfactory radiological outcomes.

Computed tomography micromotion analysis in the follow-up of patients with surgically treated pelvic fractures: a prospective clinical study

PURPOSE

High-energy pelvic fractures are complex injuries often requiring surgical treatment. Different radiological methods exist to evaluate the reduction and healing process postoperatively but with certain limitations. The aim of this study was to evaluate Computed Tomography Micromotion Analysis (CTMA) in a clinical setting for follow-up of surgically treated pelvic fracture patients.

METHODS

10 patients surgically treated for a pelvic fracture were included and prospectively followed with Computed Tomography (CT) at 0, 6, 12 and 52 weeks postoperatively. CTMA was used to measure postoperative translation and rotation of the pelvic fracture during the 52 weeks follow-up. Clinical outcomes were collected through the questionnaires EQ-5D index score and Majeed score.

RESULTS

10 patients were included with mean age (± SD, min-max) 52 (16, 31-80) years and 70% (n = 7) were males. The median (IQR, min-max) global translation from 0 to 52 weeks was 6.0 (4.6, 1.4-12.6) millimeters and median global rotation was 2.6 (2.4, 0.7-4.7) degrees. The general trend was a larger translation between 0 and 6 weeks postoperatively compared to 6-12 and 12-52 weeks. For the clinical outcomes, the general trend was that all patients started from high scores which decreased in the first postoperative follow-up and recovered to different extent during the study period.

CONCLUSION

CTMA was successfully used in the follow-up of surgically treated pelvic fracture patients. Movement in the pelvic fractures after surgical fixation was largest between 0 and 6 weeks.

Standard practice in the treatment of unstable pelvic ring injuries: an international survey

PURPOSE

Unstable pelvic ring injury can result in a life-threatening situation and lead to long-term disability. Established classification systems, recently emerged resuscitative and treatment options as well as techniques, have facilitated expansion in how these injuries can be studied and managed. This study aims to access practice variation in the management of unstable pelvic injuries around the globe.

METHODS

A standardized questionnaire including 15 questions was developed by experts from the SICOT trauma committee (Société Internationale de Chirurgie Orthopédique et de Traumatologie) and then distributed among members. The survey was conducted online for one month in 2022 with 358 trauma surgeons, encompassing responses from 80 countries (experience > 5 years = 79%). Topics in the questionnaire included surgical and interventional treatment strategies, classification, staging/reconstruction procedures, and preoperative imaging. Answer options for treatment strategies were ranked on a 4-point rating scale with following options: (1) always (A), (2) often (O), (3) seldom (S), and (4) never (N). Stratification was performed according to geographic regions (continents).

RESULTS

The Young and Burgess (52%) and Tile/AO (47%) classification systems were commonly used. Preoperative three-dimensional (3D) computed tomography (CT) scans were utilized by 93% of respondents. Rescue screws (RS), C-clamps (CC), angioembolization (AE), and pelvic packing (PP) were observed to be rarely implemented in practice (A + O: RS = 24%, CC = 25%, AE = 21%, PP = 25%). External fixation was the most common method temporized fixation (A + O = 71%). Percutaneous screw fixation was the most common definitive fixation technique (A + O = 57%). In contrast, 3D navigation techniques were rarely utilized (A + O = 15%). Most standards in treatment of unstable pelvic ring injuries are implemented equally across the globe. The greatest differences were observed in augmented techniques to bleeding control, such as angioembolization and REBOA, more commonly used in Europe (both), North America (both), and Oceania (only angioembolization).

CONCLUSION

The Young-Burgess and Tile/AO classifications are used approximately equally across the world. Initial non-invasive stabilization with binders and temporary external fixation are commonly utilized, while specific haemorrhage control techniques such as pelvic packing and angioembolization are rarely and REBOA almost never considered. The substantial regional differences' impact on outcomes needs to be further explored.

Bony Sacral Volume after Sacro-Iliac Screw Fixation of Pelvic Fractures Is Dependent on Reduction of the Anterior Pelvic Ring

Pelvic ring injuries are uncommon but serious injuries. Percutaneous sacro-iliac screw fixation (SSF) is the standard treatment for posterior stabilization of pelvic fractures. Compression forces of the SSF might cause deformity of the sacrum and the pelvic ring. The aim of this radio-volumetric study is to evaluate the morphometry of the sacrum and pelvic ring in SSF for posterior pelvic fractures. (1) Methods: We conducted a radio-volumetric study measuring the bony sacral volume before and after SSF for a pelvic fracture based on a three-dimensional reconstruction of the pre- and postoperative computed tomography scan of 19 patients with a C-type pelvic fracture. In addition to the bony sacral volume, we assessed the pelvic deformity and the load bearing axis. We compared the results of patients without anterior stabilization (Group A) to patients who had additional ORIF of the anterior pelvic ring. (2) Results: Median age of the patients was 41.2 years (±17.8). All patients received percutaneous SSF with partially threaded 7.3 mm screws. The sacral volume decreased from 202.9 to 194.3 cm3 in group A (non-operative treatment anterior, n = 10) and an increase of sacral volume from 229.8 to 250.4 cm3 in group B (anterior ORIF; n = 9). Evaluation of the pelvic deformity also reflected this trend by a decrease of the ipsilateral load-bearing angle in group A (37.0° to 36.4°) and an increase of this angle in group B (36.3 to 39.9°). (3) Conclusions: Bony sacral volume and pelvic deformity after sacro-iliac screw fixation in pelvic fractures depend on treatment of the anterior pelvic ring. Reduction and fixation of the anterior fracture shows an increase of the bony sacral volume and the load bearing angle leading to a closer to normal reconstruction of the pelvic anatomy.

Autonomous path planning for robot-assisted pelvic fracture closed reduction with collision avoidance

BACKGROUND

Robot-assisted pelvic fracture closed reduction (RPFCR) positively contributes to patient treatment. However, the current path planning suffers from incomplete obstacle avoidance and long paths.

METHOD

A collision detection method is proposed for applications in the pelvic environment to improve the safety of RPFCR surgery. Meanwhile, a defined orientation planning strategy (OPS) and linear sampling search (LSS) are coupled into the A* algorithm to optimise the reduction path. Subsequently, pelvic in vitro experimental platform is built to verify the augmented A*algorithm's feasibility.

RESULTS

The augmented A* algorithm planned the shortest path for the same fracture model, and the paths planned by the A* algorithm and experience-based increased by 56.12% and 89.02%, respectively.

CONCLUSIONS

The augmented A* algorithm effectively improves surgical safety and shortens the path length, which can be adopted as an effective model for developing RPFCR path planning.

Intelligent robot-assisted minimally invasive reduction system for reduction of unstable pelvic fractures

OBJECTIVE

Currently, minimally invasive internal fixation is recommended for the surgical treatment of unstable pelvic fractures. The premise and difficulty of minimally invasive internal fixation are minimally invasive reduction of fractures. This review aimed to investigate the indications, surgical strategy and techniques, safety, and efficacy of intelligent robot-assisted fracture reduction (RAFR) system of pelvic ring injuries.

METHODS

This retrospective study reviewed a case series from March 2021 to November 2021. A total of 22 patients with unstable pelvic fracture injuries underwent minimally invasive internal fixations. All pelvic ring fractures were reduced with our intelligent RAFR system. The robot system intelligently designs the optimal position and reduction path based on the patient's preoperative 3D CT. During the operation, the three-dimensional visualization of the fracture is realized through image registration, and the Robot completes the automatic reduction of the fracture. The global 3D point cloud error between the preoperative planning results and the actual postoperative reduction results was calculated. The postoperative reduction results of residual displacement were graded by the Matta Criteria.

RESULTS

Minimally invasive closed reduction procedures were completed in all 22 cases with our RAFR system. The average global 3D point cloud reduction error between the preoperative planning results and the actual postoperative reduction results was 3.41mm±1.83mm. The mean residual displacement was 4.61mm±3.29mm. Given the Matta criteria, 16 cases were excellent, five were good, and one was fair, with an excellent and good rate of 95.5%.

CONCLUSION

Our new pelvic fracture reduction robot system can complete intelligent and minimally invasive fracture reduction for most patients with unstable pelvic fractures. The system has intelligent reduction position and path planning and realizes stable pelvis control through a unique holding arm and a robotic arm. The operation process will not cause additional damage to the patient, which fully meets the clinical requirements. Our study demonstrated the safety and effectiveness of our robotic reduction system and its applicability and usability in clinical practice, thus paving the way towards Robot minimally invasive pelvic fracture surgeries.

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.

Simultaneous reduction and fixation of concomitant acetabular fracture and ipsilateral sacroiliac joint injury through the pararectus approach: a technical report and early radiological outcome

PURPOSE

Osteosynthesis for acetabular fractures with ipsilateral sacroiliac joint (SIJ) injuries remains challenging for orthopedic surgeons, despite the evolution of surgical approaches, such as the pararectus approach, and treatment sequences. The study aimed to describe the details of the treatment of acetabular fracture with ipsilateral SIJ injury by the pararectus approach and to report its surgical outcomes.

METHODS

We retrospectively assessed patients with acetabular fractures and ipsilateral SIJ injuries undergoing osteosynthesis by the pararectus approach over a three-year period. Evaluation parameters of the quality of reduction of both acetabulum and pelvis injuries were, among others, Matta's criteria, Lefaivre's criteria, inlet/outlet ratios, and maximal gap measured on computed tomography (CT) scans.

RESULTS

Ten patients (seven men and three women) were enrolled. Pelvic ring injuries classified as AO B2.3 and acetabular fractures involving two columns were the most common fractures, accounting for 70% and 60%, respectively. Radiological evaluation for pelvic ring injury revealed three excellent and seven good results according to Matta's criteria, as well as five excellent, three good, and one fair results according to Lefaivre's criteria. Inlet and outlet ratios were between 0.84-1.06 and 0.93-1.60, respectively. The distance of the sacroiliac joints significantly improved postoperatively in both axial and coronal views (P = 0.002). Further, the maximal articular gap and step-off of acetabular fractures on axial, coronal, and sagittal view CT scans showed statistically significant improvements after osteosynthesis.

CONCLUSION

Simultaneous reduction and fixation of acetabular fractures with ipsilateral SIJ injuries using the pararectus approach achieved satisfactory radiological outcomes.

LEVEL OF EVIDENCE

IV.

TRIAL REGISTRATION

Retrospectively registered.

Morphological Asymmetry of Pelvic Rings: A Study Based on Three-Dimensional Deviation Analysis

OBJECTIVE

To evaluate the morphological asymmetry of pelvic rings existing in healthy individuals in terms of three-dimensional (3D) geometric shapes.

METHODS

This study was a retrospective self-control study. CT images of healthy pelvises, scanned from Jan 2014 to Jan 2019, were taken from 159 subjects (88 males and 71 females) aged 20 to 59 years (39.1 ± 8.7 years). Digital pelvic ring models were reconstructed from CT images and then flipped over the corresponding sagittal planes to obtain their mirrored models. A 3D deviation analysis of a pelvic ring was conducted between the original model and its mirrored model via model registration and quantification of the geometric differences. Next, the pelvic rings were split to the left and right hipbones. The same flipping procedures as done by pelvic rings were performed for left hipbones to obtain their mirrored models. A 3D deviation analysis was also performed between the left and right hip bones. Quantitative variables representing deviation mainly included the average deviation (AD) and the maximum deviation (MD). MDs over 4 mm and 10 mm were deemed as critical levels for evaluating the severity of asymmetry as per Matta's scoring system. The quantitative assessments of the asymmetry covered pelvic rings, bilateral hip bones and the specific anatomic regions of a hip bone.

RESULTS

157 out of 159 pelvic rings (98.74%) had more than 4 mm of the MD and 27 (16.98%) of them exceeded 10 mm of the MD. The MD of pelvic rings was 1.23 times as high as that for the bilateral hip bones (7.46 mm vs. 6.08 mm, P < 0.05). The ADs of pelvic rings and bilateral hip bones were 1.28 mm and 0.94 mm, respectively (P < 0.05); 2.27% of the surface points of a pelvic ring had more than 4 mm geometric deviations compared with its mirrored model, while 0.59% (P < 0.05) of bilateral hip bones were on the same level of deviation. 119 out of 159 pelvic iliac crests (74.8%) had MDs more than 4 mm, and 15 (9.4%) reached 10 mm or more. Only 15 (9.4%) pelvises presented asymmetric features in the area of obturator foramen where the MDs exceeded 4 mm.

CONCLUSIONS

Pelvic asymmetry exists in the general population, but 3D geometric symmetry is present in specific anatomic regions. It implies that restoring the 3D symmetry of specific anatomic regions is more reliable than "restoring the symmetry of pelvic ring" in pelvic ring reduction or pelvic fixation design.

Design and evaluation of an intelligent reduction robot system for the minimally invasive reduction in pelvic fractures

Introduction

Pelvic fracture is a severe high-energy injury with the highest disability and mortality of all fractures. Traditional open surgery is associated with extensive soft tissue damages and many complications. Minimally invasive surgery potentially mitigates the risks of open surgical procedures and is becoming a new standard for pelvic fracture treatment. The accurate reduction has been recognized as the cornerstone of minimally invasive surgery for pelvic fracture. At present, the closed reduction in pelvic fractures is limited by the current sub-optimal 2D intra-operative imaging (fluoroscopy) and by the high forces of soft tissue involved in the fragment manipulation, which might result in fracture malreduction. To overcome these shortcomings and facilitate pelvic fracture reduction, we developed an intelligent robot-assisted fracture reduction (RAFR) system for pelvic fracture.

Methods

The presented method is divided into three parts. The first part is the preparation of 20 pelvic fracture models. In the second part, we offer an automatic reduction algorithm of our robotic reduction system, including Intraoperative real-time 3D navigation, reduction path planning, control and fixation, and robotic-assisted fracture reduction. In the third part, image registration accuracy and fracture reduction accuracy were calculated and analyzed.

Results

All 20 pelvic fracture bone models were reduced by the RAFR system; the mean registration error E1 of the 20 models was 1.29 ± 0.57 mm. The mean reduction error E2 of the 20 models was 2.72 ± 0.82 mm. The global error analysis of registration and reduction results showed that higher errors are mainly located at the edge of the pelvis, such as the iliac wing.

Conclusion

The accuracy of image registration error and fracture reduction error in our study was excellent, which could reach the requirements of the clinical environment. Our study demonstrated the precision and effectiveness of our RAFR system and its applicability and usability in clinical practice, thus paving the way toward robot minimally invasive pelvic fracture surgeries.

Postoperative Reduction Quality May Be the Most Important Factor That Causes Worse Functional Outcomes in Open and Closed Pelvic Fractures

Background

Data on the functional outcomes of patients with open pelvic fractures after osteosynthesis are limited, and whether open fracture is a risk factor for worse outcomes, as compared with closed fracture, remains unclear. This study aimed to compare the functional outcomes of patients with open and closed pelvic fractures and evaluate potential factors that might affect outcomes.

Methods

Overall, 19 consecutive patients with open pelvic fractures and 78 patients with closed pelvic fractures between January 2014 and June 2018 were retrospectively reviewed. All fractures were surgically treated, with a minimal follow-up period of three years. Patients’ demographic profile, associated injuries, management protocol, quality of reduction, and outcomes were recorded and analyzed.

Results

Patients with open pelvic fractures had higher new injury severity score, higher incidence of diverting colostomy, and longer length of stay. Both radiological and functional evaluations revealed no significant differences between the two groups at 1-year and 3-year evaluations. Multiple logistic regression analysis identified poor radiological outcomes (using Lefaivre criteria) and longer length of stay as risk factors for worse short-term functional outcomes. At 3-year evaluation, fair-to-poor radiological outcomes (using Matta/Tornetta and Lefaivre criteria) and the presence of diverting colostomy were potential risk factors.

Conclusions

Compared with closed pelvic fracture, open pelvic fracture was not an indicator of worse functional outcomes. Functional outcomes may be comparable between patients with open and closed pelvic fractures at different time points within three years postoperatively. Achieving anatomical reduction in a fracture is crucial, because it might affect patient satisfaction.

Nonoperative Treatment of Select Lateral Compression Type II Pelvic Ring Injuries (OTA/AO 61B2.2) Results in a Low Rate of Radiographic Displacement

OBJECTIVES

To quantify radiographic outcomes and to identify predictors of late displacement in the nonoperative treatment of lateral compression type II (LC-2) pelvic ring injuries.

DESIGN

Retrospective review.

SETTING

Two Level 1 trauma centers.

PATIENTS/PARTICIPANTS

Thirty eight patients 18 years of age or older with LC-2 pelvic ring injuries were included in the study.

INTERVENTION

Nonoperative treatment.

MAIN OUTCOME MEASUREMENTS

Crescent fracture displacement (CFD) was measured on initial axial computed tomography scan. Change in pelvic ring alignment was measured by the deformity index, simple ratio, and inlet and outlet ratios on successive plain radiographs.

RESULTS

Patients in this study had minimally displaced LC-2 pelvic ring injuries, with median initial CFD of 2 mm and median initial deformity index of 2%. No patients had a change of more than or equal to 10 percentage points in deformity index over the treatment period, but small amounts of displacement were seen on the other ratios. No patients initially selected for nonoperative treatment converted to operative treatment. No radiographic predictors of late displacement were identified. Bilateral pubic rami fractures and the presence of a complete sacral fracture ipsilateral to the crescent fracture were not associated with late displacement.

CONCLUSIONS

A spectrum of injury severity and stability exists in the LC-2 pattern. Nonoperative treatment of LC-2 injuries with low initial deformity and CFD results in minimal subsequent displacement.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Failure of internal fixation of the anterior ring for unstable pelvic fractures, the experience of a single institute

Background

This study aimed to share our experience of anterior ring fixation failure for unstable pelvic fractures and propose corresponding treatment strategies.

Materials

From January 2009 to December 2018, 93 charts of patients with pelvic fractures were retrospectively reviewed. Patients with failure of the anterior ring internal fixation within 3 months after initial surgery were analyzed. Quality of reduction was evaluated using the Majeed scoring system. Patients aging ≥ 18 years, with unstable pelvic fractures, Tile classification type B and type C pelvic fractures, combined injury of other organs that did not affect the operation and without important neurovascular damage were included. The exclusion criteria included: (1) pathological fracture, or combined with pelvic bone tumor or severe osteoporosis; (2) femoral fracture and thoracolumbar fracture; (3) open pelvic fracture; (4) Morel-Lavallée injury; (5) complicated acetabular fracture. The quality of the reduction of the anterior pelvic ring injury was evaluated on the x-ray film using the Majeed scoring system.

Results

According to the Tile classification of fracture, there were 23 cases of type B1, 17 cases of type B2, 11 cases of type B3, 28 cases of type C1, 6 cases of type C2, and 8 cases of type C3. The duration from injury to pelvic internal fixation ranged from 5 to 28 days. Seven out of 93 patients experienced failure of internal fixation of the anterior pelvic ring within 3 months, including 2 patients fixed with an external fixator and 5 patients fixed with a plate. Five patients undergoing revision surgery were followed up for 6–36 months with an average of 18 months. According to Majeed’s score at the last follow-up in the 5 patients undergoing revision surgery, there were 2 cases of excellent, 2 cases of good, 1 case of fair. The excellent and good rate reached 80%.

Conclusion

The treatment of complicated unstable pelvic fractures requires performing internal fixation surgery within 2 weeks. It is necessary to make a preoperative plan and stabilize the posterior ring first, avoiding a single steel plate crossing the pubic symphysis.

Does 3D-Assisted Operative Treatment of Pelvic Ring Injuries Improve Patient Outcome?-A Systematic Review of the Literature

Background: There has been an exponential growth in the use of advanced technologies for three-dimensional (3D) virtual pre- and intra-operative planning of pelvic ring injury surgery but potential benefits remain unclear. The purpose of this study was to evaluate differences in intra- and post-operative results between 3D and conventional (2D) surgery. Methods: A systematic review was performed including published studies between 1 January 2010 and 22 May 2020 on all available 3D techniques in pelvic ring injury surgery. Studies were assessed for their methodological quality according to the Modified McMaster Critical Review form. Differences in operation time, blood loss, fluoroscopy time, screw malposition rate, fracture reduction and functional outcome between 3D-assisted and conventional (2D) pelvic injury treatment were evaluated and a best-evidence synthesis was performed. Results: Eighteen studies fulfilled the inclusion criteria, evaluating a total of 988 patients. Overall quality was moderate. Regarding intra-operative results of 3D-assisted versus conventional surgery: The weighted mean operation time per screw was 43 min versus 52 min; for overall operation time 126 min versus 141 min; blood loss 275 ± 197 mL versus 549 ± 404 mL; fluoroscopy time 74 s versus 125 s and fluoroscopy frequency 29 ± 4 versus 63 ± 3. In terms of post-operative outcomes of 3D-assisted versus conventional surgery: weighted mean screw malposition rate was 8% versus 18%; quality of fracture reduction measured by the total excellent/good rate by Matta was 86% versus 82% and Majeed excellent/good rate 88% versus 83%. Conclusion: The 3D-assisted surgery technologies seem to have a positive effect on operation time, blood loss, fluoroscopy dose, time and frequency as well as accuracy of screw placement. No improvement in clinical outcome in terms of fracture reduction and functional outcome has been established so far. Due to a wide range of methodological quality and heterogeneity between the included studies, results should be interpreted with caution.

Matta's criteria may be useful for evaluating and predicting the reduction quality of simultaneous acetabular and ipsilateral pelvic ring fractures

BACKGROUND

Although the incidence, types, and radiological outcomes of simultaneous ipsilateral pelvic ring and acetabular fractures have been reported, there have been no reports on factors that may affect the quality of acetabular fracture reduction. Here, we evaluate the radiological outcomes of patients treated for simultaneous ipsilateral pelvic and acetabular fractures and analyze the factors that affect the quality of acetabular fracture reduction.

METHODS

We conducted a retrospective review of patients treated for simultaneous ipsilateral pelvic ring and acetabular fractures between 2016 and 2020. Factors that may predict inadequate reduction of the acetabular fracture were analyzed.

RESULTS

Data from 27 hips of 26 patients were collected. AO B2.2 and anterior columnar fractures were the most common types of pelvic ring and acetabular fractures, respectively. Univariate analysis revealed that Matta's criteria for pelvic ring fracture may be useful for predicting fair to poor quality of acetabular fracture reduction on X-rays. Furthermore, associated fractures identified by Letournel's classification system on computed tomography may be predictive of greater step-offs.

CONCLUSIONS

Associated fractures identified via Letournel's classification may contribute to inadequate reduction of acetabular fractures. Matta's criteria for pelvic ring fractures may also be useful for predicting the risk of inadequate reduction of the acetabulum on X-ray scans. These findings may be assessed intraoperatively by fluoroscopy before beginning osteosynthesis for acetabular fractures.

Exploring partial intrinsic and extrinsic symmetry in 3D medical imaging

We present a novel methodology to detect imperfect bilateral symmetry in CT of human anatomy. In this paper, the structurally symmetric nature of the pelvic bone is explored and is used to provide interventional image augmentation for treatment of unilateral fractures in patients with traumatic injuries. The mathematical basis of our solution is based on the incorporation of attributes and characteristics that satisfy the properties of intrinsic and extrinsic symmetry and are robust to outliers. In the first step, feature points that satisfy intrinsic symmetry are automatically detected in the Möbius space defined on the CT data. These features are then pruned via a two-stage RANSAC to attain correspondences that satisfy also the extrinsic symmetry. Then, a disparity function based on Tukey's biweight robust estimator is introduced and minimized to identify a symmetry plane parametrization that yields maximum contralateral similarity. Finally, a novel regularization term is introduced to enhance similarity between bone density histograms across the partial symmetry plane, relying on the important biological observation that, even if injured, the dislocated bone segments remain within the body. Our extensive evaluations on various cases of common fracture types demonstrate the validity of the novel concepts and the accuracy of the proposed method.

Erectile dysfunction and penile rehabilitation after pelvic fracture: a systematic review and meta-analysis

OBJECTIVE

To investigate the rate of erectile dysfunction (ED) after pelvic ring fracture (PRF).

DESIGN

Systematic review and meta-analysis.

METHODS

A systematic literature search of the Cochrane, EMBASE, MEDLINE, Scopus and Web of Science Library databases was conducted in January 2020. Included were original studies performed on humans assessing ED after PRF according to the 5-item International Index of Erectile Function (IIEF-5) questionnaire and fracture classification following Young and Burgess, Tile or Arbeitsgemeinschaft für Osteosynthesefragen/Orthopedic Trauma Association. Furthermore, interventional cohort studies assessing the effect of penile rehabilitation therapy with phosphodiesterase-5-inhibitors (PDE-5-I) on IIEF-5 scores compared before and after treatment were included. Results were presented as forest plots of proportions of patients with ED after PRF or mean changes on IIEF-5 questionnaires before and after penile rehabilitation. Studies not included in the quantitative analysis were narratively summarised. Risk of bias assessment was conducted using the revised tool for the Quality Assessment on Diagnostic Accuracy Studies.

RESULTS

The systematic literature search retrieved 617 articles. Seven articles were included in the qualitative analysis and the meta-analysis. Pooled proportions revealed 37% of patients with ED after suffering any form of PRF (result on probability scale pr=0.37, 95% CI: 0.26 to 0.50). Patients after 3 months of penile rehabilitation therapy reported a higher IIEF-5 score than before (change score=6.5 points, 95% CI: 2.54 to 10.46, p value=0.0013).

CONCLUSION

Despite some heterogeneity and limited high-quality research, this study concludes that patients suffering from any type of PRF have an increased risk of developing ED. Oral intake of PDE-5-I for the purpose of penile rehabilitation therapy increases IIEF-5 scores and may relevantly influence quality-of-life in these patients.

PROSPERO REGISTRATION NUMBER

CRD42020169699.