Biomechanical Evaluation of Different Minimally Invasive Internal Fixation Methods for the Anterior and Posterior Rings in Tile C Pelvic Fractures

ObjectiveTo investigate the clinical effect of robot-assisted treatment of unstable pelvic fractures through a percutaneous iliac lumbar double rod fixation combined with a percutaneous pelvic anterior ring INFIX (internal fixator) fixation.MethodsThis was a retrospective analysis of 17 cases of unstable anterior and posterior pelvic ring fractures treated between April 2016 and October 2018 by the third Ti-robot system produced in China. The posterior ring was supported with an iliac lumbar double rod fixation and the anterior ring with an INFIX fixation. Operation time and peri-operative bleeding were recorded. The reduction of pelvic fracture displacement was evaluated by Matta score, the post-operative results were evaluated according to Majeed score, and the complications were recorded.ResultsTwelve males and five females, aged 21–71 years (mean 40.1 ± 3.8 years) were followed up for three to 12 months, (median 6.7 months). Tile typing showed seven B1 type, two B2 type, and eight C1 type cases. Operation time was 90–160 minutes (mean 112.9 ± 16.8 minutes), bleeding was 80–150 mL (mean 105.9 ± 20.6 mL). X-ray three to five days after operation was evaluated by Matta score as excellent in 15 and good in two cases. Majeed score at last follow-up was 85–98 points, excellent in 17 cases. Two cases of lower extremity deep vein thrombosis received an inferior vena cava filter. The filters were removed after two weeks. One case showed incision fat liquefaction healing and the wound healed three weeks after surgery.ConclusionOrthopedic robot-assisted treatment of unstable pelvic fractures by a percutaneous iliac lumbar double rod fixation and a percutaneous pelvic anterior ring INFIX fixator was minimally invasive and feasible. A prospective study is needed.

Objective To investigate the feasibility of Legacy pedicle screw system plus minimally invasive technique in treatment of Tile type C pelvic fracture and evaluate its therapeutic effects.Methods From January 2008 to March 2010, 12 patients with closed Tile type C pelvic fractures were treated with Legacy pedicle screw system plus minimally invasive technique.There were seven males and five females, at age range of 21-60 years (average 39.6 years).All patients had sacrum fractures of the posterior pelvic rings.The anterior pelvic ring fractures included unilateral ischiadic ramus fractures in four patients and bilateral ischiadic ramus fractures in eight.Three patients were combined with shock.The anterior pelvic rings were fixed with minimally invasive reconstruction plates and the posterior pelvic rings fixed with minimally invasive technique plus Legacy pedicle screw system. Results The operation lasted for average 90 minutes (range, 80-110 minutes) , with average intraoperative blood loss of 105 ml (range, 80-150 ml).All patients were followed up for average 18 months (range, 6-32 months), which showed that all patients got satisfactory reductions and that the fractures were healed at one stage, with average period of 11.5 weeks (range, 9-13 weeks).There occurred no infections, failures of internal fixations or nerve injuries.According to improved Lindahl standard of pelvic injury function assessment, the result was excellent in 10 patients and good in two, with average score of 78.6 points. Conclusions Under master of the surgical indications, Legacy pedicle screw system plus minimally invasive technique takes advantages of minor trauma, less intraoperative fluoroscopy, short operation time, good curative resuhs and few complications in treatment of Tile type C pelvic fractures by fixation of the posterior pelvic rings and reconstruction of the anterior pelvic rings. Key words: Pelvis; Surgical procedures, minimally invasive; Fracture fixation

To evaluate the biomechanical stability of dual anterior subcutaneous internal fixation (INFIX) in pelvic C1 fractures by finite element analysis, and to compare it with INFIX combined with sacroiliac screws to determine whether it is sufficient to replace the combined fixation of anterior and posterior rings. The pelvic CT data of a 43-year-old female volunteer were imported into the computer and the normal pelvic model and pelvic C1 fractures model were constructed using Mimics, Workbench and other software. The latter was fixed with dual INFIX and INFIX combined with sacroiliac screws, respectively. First, the effectiveness of the normal pelvic model in anatomical landmarks, stress conduction and displacement distribution was verified. Then, a vertical downward load of 500 N was applied to the two internal fixation models to simulate the standing and sitting positions of the human body, and the displacement of the anterior and posterior ring fractures ends, the stress of the internal fixation and the stress of the nail channel in the bone were collected. The model passed the validity verification. The maximum displacement of the anterior and posterior ring fractures in the standing dual INFIX group were 0.861 mm and 4.128 mm, respectively, which were both smaller than the 0.152 mm and 0.293 mm in the combined fixation group. The displacement of the posterior ring fractures in the sitting dual INFIX group was 3.757 mm, which was larger than the 0.560 mm in the combined fixation group, while the maximum displacement of the anterior ring fractures was 0.221 mm, which was not much different from the 0.194 mm in the combined fixation group. The maximum stress of internal fixation in the standing dual INFIX group was greater than that in the combined fixation group, while the opposite was true in the sitting position. The maximum stress of each internal fixation was lower than the yield strength of titanium alloy 790 MPa. The maximum stress of the nail channel in the standing and sitting daul INFIX groups was lower than that in the combined fixation group, and the stress of all nail channels was lower than the strength limit of bone 290 to 540 MPa. The stability of dual INFIX fixation in anterior and posterior ring fractures is generally inferior to that of INFIX combined with sacroiliac screw fixation. Although simple dual INFIX fixation can share part of the load for the posterior ring, the posterior ring will still have a large displacement, so the fixation of the posterior ring is very important. In addition, the fixation strength and stability of dual INFIX in the anterior ring are better than INFIX. When INFIX cannot provide sufficient strength to stabilize the anterior ring fractures, dual INFIX will be a good choice.

Objective To analyze the relationship between the number of pelvic ring fractures, the location of fracture and Tile type of pelvic fracture and pelvic fracture healing status. To discuss how to understand the pelvic malunion, severe pelvic malunion and bony pelvis deformity （destruction） in Classification of the Impairment Related to Injury. Methods One hundred and ninety-eight cases of evaluation of body impairment class of pelvic fracture caused by traffic accident accepted by Zhongcheng Institute of Forensic Science in 2016 were collected. The cases were statistically analyzed in terms of the distribution of the number of pelvic ring fracture, the location of pelvic ring fracture and Tile type of pelvic fracture in various healing statuses. Results There were 16 cases without pelvic ring fracture, 18 cases of single pelvic ring fracture, 91 cases of 2 pelvic ring fractures, 73 cases of 3 or more pelvic ring fractures, 136 cases of anterior or posterior pelvic ring fractures, 46 cases of simultaneous anterior and posterior ring fractures. There were 34 cases of Tile A type, 130 cases of Tile B type and 24 cases of Tile C type. Statistical analysis results showed that, the differences in distribution of the number of pelvic ring fracture, the location of pelvic ring fracture and Tile type of pelvic ring fracture in various healing statuses had statistical significance （P<0.05）. Conclusion In determination of the healing status of pelvic fracture, preliminary judgment can be made by using the number of pelvic ring fracture, status of pelvic ring fracture and Tile type of pelvic fracture. Caution is required when dealing with single pelvic fractures （including dislocations）, and determining the destruction of bony pelvis.

Objective To evaluate the modified Stoppa approach in treatment of patients with pelvic and acetabular fractures. Methods We analyzed the outcomes of 26 consecutive patients with fractures of the pelvic ring and 9 patients with acetabular fractures who had been treated between March 2008 and December 2009 by open reduction and internal fixation through the modified Stoppa approach. The modified Stoppa approach was made through a low midline incision to fix the pelvis and acetabular fractures. By Tile classification, the 26 pelvic fractures included 2 cases of B1, 4 of B2, 7 of B3, 4 of C1-1, 2 of C1-2, 4 of C1-3, and 3 of C2. By Letournel classification, the 9 acetabular fractures included one case of anterior column, 3 transverse cases, 2 T type cases, one anterior column plus posterior transverse case, and 2 cases of both columns. For pelvic fractures, the modified Stoppa approach was used exclusively in 10 cases, in combination with the iliac fossa approach in 15 cases, and in combination with the posterior approach in one case. For acetabular fractures, the modified Stoppa approach was used exclusively in 3 cases, in combination with the Kocher-Langenbeck approach in 4 cases, and in combination with the Kocher-Langenbeck and iliac fossa approaches in 2 cases of both columns. Results The average operation time was 90 min (65 to 135 min)and the blood loss averaged 320 mL(150 to 1200 mL) in all but one patient with obsolete fracture of both columns. The reductions of the pelvic and acetabular fractures were all excellent and good. Twenty-two patients with pelvic fracture were accessible for an average follow-up of 4 months. Among them, one case of plate breakage and one case of screw loosening were found. Seven patients with acetabular fracture were accessible for an average follow-up of 4 months. One case of mild hip flexion and one case of ectopic ossification were found in them but there was no femoral head necrosis. Satisfactory functional results were achieved in the 29 cases that had been followed up. Conclusion The modified Stoppa approach may be used exclusively or in combination with other approaches to treat pelvic and acetabular fractures effectively, providing advantages of easy manipulation and a low complication rate. Key words: Pelvis; Acetabulum; Fracture; Surgical approach

Objective To explore the clinical characteristics of the floating injury of symphysis pubis and clinical outcome of open reduction and internal fixation.Methods A retrospective study was conducted to analyze the 48 patients who had been treated in our department with open reduction and internal fixation for the floating injury of Symphysis pubis from January 2008 to January 2013.There were 31 males and 17 females,with an average age of 36.5 years (range,20 to 61 years).Thirty-five patients were injured in traffic accidents and 8 were injured by falling injuries,and the other 5 were crushed by maehine.Fortyfive cases were complicated with fractures of the posterior pelvis ring; 14 cases were complicated with acetabular fractures; 17 cases were complicated with extremity fractures; 1 1 cases were complicated with thoracic and abdominal injuries and 6 cases were associated with urogenital system injury.The average period from trauma to operation was 7 days (range,3 to 25 days).Operation was performed under general anesthesia.The bilateral pubic ramus fractures were fixed with reconstruction plate in 41 cases,and 7 cases were fixed with cannulated screw through minimally invasive method.Forty-one cases with posterior ring fractures were fixed simulaneously.Results There were 44 patients being followed up with an average period of 16 months (range,12 to 30 months).All the fractures of the pelvis were clinically healed with an average period of 12.6 weeks (range,10 to 16 weeks).According 图o the Majeed score system,the functional results were exc ellent in 30 cases,good in 10 cases,and fair in 4 cases; The average score was 81.5 (range,60 to 100).Two patients who had wound fat liquefaction at 3 days after operation were healed by dressing changing; 8 patients got deep vein thrombosis at 10 days (range,5 to 15 days) after operation were cured by conservative treatment; 3 patients got supra pubic pain at 6 days (range,5 to 7 days) after operation were healed by oral non steroidal anti-inflammatory analgesic drugs and physical therapy in one year.Conclusion Floating injury of symphysis pubis is a kind of severe pelvic fracture which affects the stability of pelvic ring.Open reduction and internal fixation is a good method to stabilize the pelvis ring and to get early rehabilitation.This may contribute to good clinical resuls and good function. Key words: Pelvis; Pubic symphysis; Fractures; Fracture fixation, internal

Objective To determine the curative effect of stabilizing unstable pelvic ring fracture using the anterior subcutaneous internal fixator (INFIX). Methods From July 2013 to June 2014, 15 cases who suffered from anterior pelvic ring fracture were treated with the device. There were 11 males and 4 females, with mean age of 38. 5 years (range, 23-65 years). Eight cases sustained fracture in traffic accidents, 4 in high falls, and 3 in crush injury. According to the Young-Burgess and AO/OTA classification systems, type APC2 or 61-B1 was noted in one case, LC1 or 61-B2.1 in 4 cases, LC2 or 61-B2. 2/61-B2. 3 in 6 cases, and VS or 61-C1/61-C2 in 4 cases. Basic method in anterior ring fixation was one pedicle screw was respectively inserted into the area between the anterior superior iliac spine and anterior inferior iliac spine of both sides. The precontoured rod was then tunneled subcutaneously from one screw to the other. For the stable posterior injury in pelvic ring fracture, the anterior pelvic ring was stabilized only using the technique. For the unstable posterior injury in pelvic ring fracture, the anterior and posterior ring were both fixed using the technique.During follow-up visits, patients' tolerance to the device, wound infection, myositis ossificans, internal fixation lessening, and lateral femoral cutaneous nerve injury were evaluated. Results Follow-up ranged from 6-12 months (mean, 7. 5 months). The device was well tolerated by the patients for comfort. None had surgical site infection and internal fixation loosening. Injuries healed without loss of reduction at the 3-month follow-up. Injury of the lateral femoral cutaneous nerve at the both side was reported in 4 cases and at one side in 2 cases, but all restored 3 month after operation. Conclusion The reported technique is minimally invasive with few complications and reliable results, hinting an ideal method to stabilize the anterior pelvic ring fracture. Key words: Pelvis; Fracture fixation, internal; Surgical procedures, minimally invasive

BackgroundClosed reduction and internal fixation is the key to early and minimally invasive treatment of pelvic fractures in patients with severe trauma. Although the pelvic unlocking closed reduction device has been promoted to a certain extent, the therapeutic effect and surgical strategies for treating severe trauma have not been clearly clarified. Our study was aimed to explore the therapeutic effect and surgical strategy skills of the pelvic unlocking closed reduction device in treating severe traumas combined with pelvic fractures.MethodsData were retrospectively collected from 13 patients with severe traumas undergoing pelvic unlocking closed reduction for pelvic fractures in our hospital between July 2021 and December 2022. Seven males and six females aged 48(18~69), 46.4±16.7 years were involved. The operation time, times of fluoroscopy, and blood loss were recorded intraoperatively. Postoperative complications, and fracture healing time were recorded. The Matta and Majeed scales were used to evaluate fracture reduction and clinical efficacy respectively.ResultsThe time from injury to surgery was 7(4~14), 8.2±3 days. No wound infection, loosening or breakage of internal fixation, or loss of reduction occurred. The clinical healing time was 3(3~5), 3.5±0.7 months. Three cases suffered paresthesia on unilateral anterolateral thigh. According to the postoperative imaging Matta scores, 12 cases were excellent and 1 case was good, with an excellent rate of 12/13. At the last follow-up, the Majeed functional scores were excellent in all 13 cases.ConclusionsFor patients with severe trauma combined with pelvic fracture, the pelvic unlocking and reduction device can be used for minimally invasive internal fixation at an early stage as long as their vital signs are stable. In this study, we summarized and advocated the 'turn-back order' reduction and internal fixation philosophy of 'posterior-ring unlocking - anterior ring to posterior ring reduction stabilization - posterior ring to anterior ring internal fixation placement' in pelvic closed reduction and internal fixation surgery.

Computer-aided automatic planning and biomechanical analysis of a novel arc screw for pelvic fracture internal fixation

Objective To evaluate the clinical efficacy of 3D image-guided minimally invasive screw internal fixation in the treatment of Tilt pelvic fracture in middle-aged and elderly (45-74years) patients. Methods A retrospective analysis including 35 middle-aged and elderly patients with Tilt pelvic fracture treated with the minimally invasive screw internal fixation was done from June 2015 to January 2017. Fifteen males (42.9%) and 20 females (57.1%). The age range was 45 to 73 years with an average of (56.4±3.7) years. According to the Tile classification: 23 cases was B2.1 type, 9 cases was B2.2 type and 3 B3 type. The posterior pelvic ring injuries had 23 DenisⅠtype, and 12 DenisⅡtype. The operative incision, blood loss during insert screw, time of operation, reduction quality, Majeed pelvic fractures function scores at the last follow-up and postoperative complications were recorded to evaluate its clinical effect. Results All patients had follow-up for an average of (6.9±1.9) months, range from 3 to 12 months. Length of incision was (2.7±1.5) cm, range from 1 to 4 cm. The time of each screw insertion was (29.4±1.7) min, range from 20 to38 min. Blood loss for screw insertion was too small to count. The quality of anterior pelvic ring fractures reduction were evaluated according to Matta standardization, 27 cases were excellent, 4 cases were good and 4 moderate, rate of excellent to good reduction was 88.6%. The quality of posterior pelvic ring fractures reduction were 27 excellent, 5 good and 3 moderate, the excellent to good rate of reduction was 91.4 %. The Majeed standardization showed 23 cases were excellent, 6 cases were good and 6 cases were moderate, the excellent to good rate of healing was 82.9%. There were no pain, wound infection, nerve injury, heterotopic ossification, thrombosis complications occurred. Conclusion The 3D image-guided minimally invasive screw internal fixation is a precise, safe, less trauma and low complications for middle-aged and elderly patients with Tilt pelvic fractures, it is a possible ideal method for clinics. Key words: Pelvis; Fractures; Minimally invasive surgical procedures; Surgery, computer-assisted; 3D printing

Background: An open-book pelvic fracture is used to describe any fracture that significantly disrupts the pelvic ring of human body. Internal and external fixation in treating open book pelvic fractures are two broadly used treatment methods. But we have very few comparative data regarding this issue. The aim of this study was to compare both internal and external fixation methods in the treatment of open book pelvic fractures. Methods: This prospective comparative study was conducted at the Department of Orthopaedic Surgery in Shaheed Mansur Ali Medical College, Sirajganj, Bangladesh and The National Institute of Traumatology & Orthopaedic Rehabilitation (NITOR) during the period from January 2016 to December 2018. In total 100 patients with open-book pelvic fracture were obeyed all the inclusion and exclusion criteria and completed the full tenure of the intervention were finalized as the study population. Total population were divided into two groups. In Group I there were 50 participants who were treated by internal fixation method and in Group II there were 50 participants who were treated by external fixation method. Data were analyzed by SPSS Version 20 and disseminated by MS Office programs. Result: In the final follow-up of this study among total participants, there were 34 excellent, 30 good, 16 fair and 20 poor results. But, In Group I, 56% got excellent and 38% got good result. Besides these, only 4% got fair and 2% got poor result. On the other hand, the highest 38% participants got poor result. Then 28%, 22% and 12% got fair, good and excellent results respectively. This difference was statistically highly significant, the p-value was 0.013. Conclusion: After completing this comparative study it was found that the internal regarding outcome and complications the internal fixation method is better than external fixation method in treating open-book pelvic fracture.

To explore the effectiveness of reduction robot combined with navigation robot-assisted minimally invasive treatment for Tile type B pelvic fractures. Between January 2022 and February 2023, 10 patients with Tile type B pelvic fractures were admitted. There were 6 males and 4 females with an average age of 45.5 years (range, 30-71 years). The fractures were caused by traffic accident in 5 cases, bruising by heavy object in 3 cases, and falling from height in 2 cases. The interval between injury and operation ranged from 4-13 days (mean, 6.8 days). There were 2 cases of Tile type B1 fractures, 1 case of Tile type B2 fracture, and 7 cases of Tile type B3 fractures. After closed reduction under assistance of reduction robot, the anterior ring was fixed with percutaneous screws with or without internal fixator, and the posterior ring was fixed with sacroiliac joint screws under assistance of navigation robot. The time of fracture reduction assisted by the reduction robot was recorded and the quality of fracture reduction was evaluated according to the Matta scoring criteria. The operation time, intraoperative fluoroscopy frequency and time, intraoperative bleeding volume, and incidence of complications were also recorded. During follow-up, the X-ray film of pelvis was taken to review the fracture healing, and the Majeed score was used to evaluate hip joint function. The time of fracture reduction was 42-62 minutes (mean, 52.3 minutes). The quality of fracture reduction according to the Matta scoring criteria was rated as excellent in 4 cases, good in 5 cases, and poor in 1 case, with excellent and good rate of 90%. The operation time was 180-235 minutes (mean, 215.5 minutes). Intraoperative fluoroscopy was performed 18-66 times (mean, 31.8 times). Intraoperative fluoroscopy time was 16-59 seconds (mean, 28.6 seconds). The intraoperative bleeding volume was 50-200 mL (range, 110.0 mL). No significant vascular or nerve injury occurred during operation. All patients were followed up 13-18 months (mean, 16 months). X-ray films showed that all fractures healed with the healing time of 11-14 weeks (mean, 12.3 weeks). One case of ectopic ossification occurred during follow-up. At last follow-up, the Majeed score was 70-92 (mean, 72.7), and the hip joint function was rated as excellent in 2 cases and good in 8 cases, with the excellent and good rate of 100%. The reduction robot combined with navigation robot-assisted minimally invasive treatment for Tile type B pelvic fractures has the characteristics of intelligence, high safety, convenient operation, and minimally invasive treatment, which can achieve reliable effectiveness.

BACKGROUND: As our population ages, the incidence of pelvic fragility fractures will rise accordingly. Despite these fractures having similar mortality rates to proximal femur fractures, there exist discrepancies between the management of these injuries. Although a number of pelvic fragility fractures can be treated successfully with conservative means, early treatment with appropriate surgical means should be considered in those failing conservative treatment or with unstable fracture patterns. CASE REPORT: We present an 84-year-old female who sustained a pelvic fragility fracture after a low-energy fall. Despite adequate conservative treatment, she was unable to mobilise. She was taken for anterior and posterior fixation, using our modified minimally invasive subcutaneous technique (the Bridging Infix) for anterior fixation. At the six-week follow-up she had regained full independent mobility. She had three syncope-related falls during this period, but radiographs revealed no sign of implant displacement. One year after her surgery she had complete union of her fracture, good function and no desire to have the implant removed. DISCUSSION: With the expected increase in pelvic fragility fractures due to the growing elderly population, our understanding of these injuries has begun to change. Occult posterior ring injuries have been described in up to 80% of cases, while fracture progression to unstable patterns can occur in up to 15% of stable patterns. Despite conservative management being the primary treatment of choice, these patients suffer morbidity and mortality rates comparable to proximal femur fractures. Early appropriate surgical management should be considered in patients failing to mobilise. Various surgical techniques have been described, each with their own advantages and disadvantages. Newer minimally invasive techniques are gaining favour, especially for use in elderly patients. These constructs combine the low profile benefits of internal plate fixation with ex-fix principles. CONCLUSION: The Bridging Infix is a modified technique for minimally invasive subcutaneous anterior pelvic fixation. Its use can strongly be considered by even the general orthopaedic surgeon in cases where patients are too frail for extensive or invasive surgeries, such as open reduction and internal fixation with plate and screws. Level of evidence: Level 5 Keywords: pelvic fracture, anterior pelvic fixation, elderly, minimally invasive

Improved outcome after early fixation of acetabular fractures

The aim of this study is to explore the clinical outcome and indications in treating anterior ring injury of Tile C pelvic fracture with minimally invasive internal fixation.We retrospectively reviewed 18 patients (aged 25–62, 34.2 ± 7.4) with 26 pelvic anterior ring injuries of Tile C pelvic fracture treated with minimally invasive internal fixation in our hospital were from January 2012 to August 2016. Two cases were pubic symphysis diastasis, 15 were anterior ring fracture (7 were bilateral), and 1 was vertical displacement of pubic symphysis associated with pubic ramus fracture. According to Tile classification, 8, 4, and 6 cases were types C1, C2, and C3, respectively. All patients accepted the operation of pelvic fractures on both rings, while the anterior ring injuries were treated with minimally invasive internal fixation. The period from injury to operation was 5 to 32 days (11.2 ± 3.7). Four patients had pubic symphysis diastasis or pelvic anterior ring fracture medial obturator foramen reduced with modified Pfannenstiel incision and fixed with cannulated screws, 14 patients (22 fractures) had a fractured lateral obturator foramen reduced with modified Pfannenstiel incision associated with small iliac crest incision and fixed with locking reconstruction plates. Clinical data, such as operation time, intraoperative bleeding, Matta standard to assess the reduction quality of fracture, and complications, were collected and analyzed.The operation time ranged from 30 to 65 minutes (42.8 ± 18.7), and the intraoperative bleeding volume was 30 to 150 mL (66.5 ± 22.8). All cases were continuously followed-up for 16 to 42 months (30.2 ± 4.6). All fractures were healed between 3 and 9 months postoperatively (4.9 ± 2.7 months). According to the Matta standard assessment, 18, 7, and 1 cases were excellent, good, and fair, respectively, with a 96.2% (25/26) rate of satisfaction. Neither reduction loss, fixation failure, nor infection occurred; complications included 1 patient with fatal liquefaction, 1 patient had lateral femoral cutaneous nerve injury, and 1 patient complained of discomfort in the inguinal area due to fixation stimulation.Minimally invasive internal fixation for pelvic anterior ring injury in Tile C pelvic fracture has the advantages of less damage, safer manipulation, less complications, and good prognosis.