Biomechanics and clinical outcomes of “barrel handle” connecting rods used in INFIX internal fixation for unstable pelvic fractures: a cadaveric biomechanical study and retrospective cohort study

Biomechanics and clinical outcomes of “barrel handle” connecting rods used in INFIX internal fixation for unstable pelvic fractures: a cadaveric biomechanical study and retrospective cohort study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Biomechanics and clinical outcomes of “barrel handle” connecting rods used in INFIX internal fixation for unstable pelvic fractures: a cadaveric biomechanical study and retrospective cohort study Hongfen Chen, Gen Wu, Sushuang Ma, Yanbing Li, Hua Zhong This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4590388/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background This study aimed to compare the biomechanical stability and clinical outcomes of a bent “barrel handle” connecting rod with a conventional “arc” rod when using the anterior subcutaneous internal fixator (INFIX) for unstable pelvic fractures. Method Type C1 pelvic ring injury model specimens were created by performing sacral foramen and pubic ramus osteotomies in 16 cadaveric pelvises. The models were randomly divided into group A (INFIX S1 screw fixation using a “barrel handle” connecting rod) and group B (INFIX S1 screw fixation using an “arc” connecting rod). Each model underwent vertical loading of 200–800 N, and the horizontal and vertical displacement distances of the fractured ends of the pubic ramus were recorded at 200, 400, 600, and 800 N. The treatment outcomes of 37 patients with unstable pelvic fractures were retrospectively evaluated. Among these, 15 patients were treated with the INFIX using the “barrel handle” connecting rods, while 22 were treated with the INFIX using the “arc” connecting rod. Outcome measures were postoperative complications (ectopic ossification, anterior exothelial nerve injury, infection), fracture reduction quality (Matta score), and postoperative function (Majeed score). Results The experiments showed no significant differences between groups A and B in the horizontal and vertical displacements after vertical compression. Among the 39 clinical cases, two patients were lost to follow-up. The demographic characteristics (sex and age), fracture classification, Injury Severity Score, and body mass index of the two groups were not comparable (P > 0.05). There were no significant differences between the two groups in fracture reduction quality, postoperative function, and postoperative complications, except for ectopic ossification. The incidences of anterior exothelial nerve injury and wound infection were significantly lower in the group treated with the INFIX using the “barrel handle” connecting rod than in the group treated with the INFIX using the “arc” connecting rod. Conclusion The INFIX using a “barrel handle” connecting rod achieves similar biomechanical stability and favorable clinical outcomes compared with the INFIX using an “arc” connecting rod. Furthermore, use of the INFIX with “barrel handle” connecting rods significantly reduces the incidences of postoperative wound infection and anterior exocortical nerve injury. Barrel handle-shaped INFIX Pelvic fracture Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Unstable pelvic fractures most often occur in association with high-energy injuries. Although their incidence is low, accounting for approximately 1.5–3.9% of all fractures, unstable pelvic fractures are characterized by high rates of disability and mortality ( 1 ). Early surgical intervention has been underscored in various studies for its pivotal role in pain management, facilitation of early mobility, and prevention of chronic pelvic instability and resultant disability( 2 ). Traditional approaches for treating pelvic fractures include open reduction with internal plate fixation or external fixators. However, these methods carry risks of vascular and nerve injury, as well as inguinal hernia ( 3 ). External fixation frames are primarily used for emergency injury control to stabilize unstable pelvic fractures and promptly restore hemodynamic stability. However, the common complications of external fixation are postoperative nail tract infection, failure of external fixation, and restricted joint movement due to the presence of external fixation frames ( 4 , 5 ). The anterior subcutaneous internal fixator (INFIX) is increasingly being used to treat unstable pelvic fractures because of its advantages over previous pelvic fixation techniques, including a shorter surgery time, reduced bleeding, lower infection rates, and faster recovery ( 6 , 7 ). However, the incidence of lateral femoral cutaneous nerve injury or irritation following internal fixation with the INFIX with the “arc” connecting rod is as high as 26.3%. Most patients experience symptom relief or resolution after removal of the internal fixation, indicating that this nerve injury is not a result of surgical injury, but rather is associated with the INFIX itself ( 8 – 10 ). Because of the generally slender and small size of the Asian body, pelvic fixation with the INFIX may pose a higher risk of anterolateral femoral cutaneous nerve (LFCN) injury in Asian patients than in patients in Western countries. Additionally, the screw head may exert pressure on the skin, leading to wound infection, skin necrosis, exposure of the INFIX, and subsequent complications. To address these concerns, we modified the shape of the connecting rod by bending it into a “barrel handle” configuration. We then evaluated the biomechanical stability of the INFIX with the “barrel handle” connecting rod and compared the clinical effects of pelvic fixation with the INFIX with the “barrel handle” connecting rod versus the INFIX with the “arc” connecting rod. 2. Methods 2.1 In vitro experiments 2.1.1 Materials Sixteen adult pelvic specimens (from 9 males and 7 females) were embalmed prior to biomechanical testing. These pelvic specimens are all from body donations. In each specimen, the femur was preserved at a length of approximately 15 cm, while the lumbar spine was preserved to the fifth lumbar vertebra (L5). The soft tissues were removed, and the anterior and posterior sacroiliac ligaments, sacral spines, and sacral tubercle ligaments were preserved. Additionally, all ligamentous attachments from L5 to the pelvis were preserved. All pelvic specimens were radiographed to exclude the presence of tumors, tuberculosis, osteoporosis, or other diseases. The specimens were stored at − 30°C. 2.1.2 Operation A fracture line with a 2.0-mm gap was created on the upper and lower branches of the pubic bone on one side using an electric pendulum saw. The sacrum was vertically cut ipsilaterally through the Denis 2 zone, and the fracture line was maintained with a 2.0 mm gap to create a Tile C1 type unstable pelvic fracture model. All specimens were prepared by the same operator (Fig. 1 A, 1 B). The model specimens were randomly divided into groups A and B, each consisting of eight specimens. Sacroiliac fixation (n = 16): a single 7.3 mm × 90 mm hollow screw (Synthes) was used to fixate S1, ensuring that the screw passed through the sacroiliac joint and the fracture site, and crossed the midline of the S1 vertebral body after being inserted from the iliac bone. Group A (n = 8): two 6.5 mm × 70 mm multiaxial pedicle screws (Synthes Company) were inserted through the plane of the bilateral anterior and inferior iliac spines. The screw heads contacted the bone surface, and the 6-mm INFIX connecting rod (Synthes Company) was bent into a “barrel handle” shape for connection and fixation (Fig. 1 C, 1 D). Group B (n = 8): two 6.5 mm × 70 mm multiaxial pedicle screws (Synthes) were inserted through the plane of the bilateral anterior and inferior iliac spines. The distance between the screw heads and the bone surface was approximately 2 cm, and the 6-mm INFIX connecting rods (Synthes) were bent into an “arc” shape and fixed. One Kirschner needle was inserted on each side of the pubic ramus and sacral fractures in all specimens, and the horizontal and vertical displacement values between the two Kirschner needles were measured and recorded during pelvic compression (Fig. 1 E, 1 F). The L5 vertebral body and distal bilateral femur in all specimens were immobilized using self-coagulating dental tray powder resin and mounted onto the Electroforce 3510 biomechanical testing machine (Ph.D., USA) for assessment (Fig. 2 ). A loading speed of 20 N/s was applied to induce axial compression at the upper sacral base. The distance between the pubic branch and the Kirschner needle at the sacral fracture endpoint was recorded at loads of 200 N, 400 N, 600 N, and 800 N. The resulting distances represented the displacements of the fracture ends. 2.2 Cases The retrospective cohort study evaluated 37 patients with unstable pelvic fractures who were admitted to the Trauma Center of the Fifth Affiliated Hospital of Southern Medical University between September 2020 and October 2022. Patients younger than 18 years and those with pathological fractures were excluded from the study. Prior to undergoing surgery, all patients underwent comprehensive imaging evaluations, including pelvic radiography (anteroposterior, inlet, and outlet views) and computed tomography. Two experienced orthopedic surgeons independently reviewed the imaging data and used the Tile pelvic fracture classification criteria to categorize each fracture. Patient-specific details, such as sex, age, body mass index (BMI), Injury Severity Score (ISS), Tile fracture classification, and follow-up duration, were meticulously recorded. Postoperative outcomes were assessed based on radiological fracture evaluation, functional scoring, and the occurrence of complications such as ectopic ossification, anterior exocutaneous nerve injury, and wound infection. 2.2.1 Operation The patients were positioned in a supine position on a fluoroscopic operating table and received conventional anesthesia. In cases where there was injury and instability of the posterior pelvic ring requiring internal fixation, screw fixation was performed as the primary intervention. A standardized surgical approach was used for all patients, commencing with a 3-cm oblique incision at the anterior superior iliac spine. Subsequently, meticulous dissection was carried out within the interfascial plane separating the tensor fascia lata and sartorius muscles. A pedicle screw detector was used to perform precise screw placement in the iliac bone between the inner and outer cortical plates, while precautions were taken to ensure that there was no breach through the bone cortex. Two multiaxial pedicle screws (6.5 mm diameter, 70 mm length) were meticulously inserted. A 6-mm-diameter titanium rod, tailored to the appropriate length, was contoured into either a “barrel handle” or an “arc” configuration, depending on the assigned fixation group. Subsequently, a subcutaneous tunnel was created to connect and secure the bilateral pedicle screws with the contoured rod. In the group treated with the INFIX with the “barrel handle” connecting rod (group 1), the pedicle screw heads were in direct contact with the bone surface. In the group treated with the INFIX with the “arc-shaped” connecting rod (group 2), a minimum distance of 2 cm was maintained between the pedicle screw heads and the bone surface to minimize the risk of nerve and vascular compression caused by the connecting rod. 2.2.2 Assessment of fracture reduction quality Postoperatively, the reduction quality for anterior pelvic ring fractures was immediately assessed by measuring the maximum displacement distance of the fracture on anteroposterior, inlet, and outlet radiographs. The evaluation criteria used in this study followed the classification system introduced by Tornetta and Matta ( 11 ). Fracture displacement distances were classified as preferred ( 20 mm). For the purpose of this study, fracture reduction was regarded as satisfactory if the displacement distance was categorized as preferred or good. 2.2.3 Postoperative management and follow-up During the postoperative period, patients were strongly encouraged to initiate early lower extremity exercises, within tolerable pain limits, to mitigate the risk of deep vein thrombosis. Partial weightbearing was typically initiated 1 month after surgery for Tile B fractures, and 2 months after surgery for Tile C fractures; the initiation of partial weightbearing was contingent upon radiographic confirmation of complete fracture consolidation. Postoperative functional assessment was performed in accordance with the Majeed scale ( 12 ). Patient follow-up was conducted via telephonic interviews or outpatient consultations. During the final follow-up visit, patients were requested to complete the Majeed score questionnaire, which encompassed domains such as pain, work functionality, sitting ability, sexual intercourse, standing capacity, walking distance, and gait. The Majeed score was categorized into four grades: excellent (> 85), good (70–84), fair (55–69), and poor (< 55). 2.2.4 Statistical analysis Statistical analysis was conducted using IBM SPSS Statistics for Windows, version 23.0 (Armonk, NY, USA). The t-test and Pearson's chi-squared test were used as the statistical methods. P values lower than 0.05 were deemed to indicate statistically significant differences. 3. Results 3.1 Specimen experiments None of the specimens exhibited failure when subjected to a load of 800 N. The average displacement distances of the fractured ends in both the anterior and posterior pelvic rings in the two groups under various loads are summarized in Table 1 . The results demonstrate an increasing trend in fracture displacement distances with greater loads. When the same loads were compared, group A displayed relatively smaller average displacement distances than group B. However, statistical analysis revealed no significant differences between the two groups (P > 0.05). 3.2 Clinical cases Group 2 patients (INFIX with “arc” connecting rods) exhibited postoperative screw exposure, while the screws in group 1 patients (INFIX with “barrel handle” connecting rods) were visually remote from the skin intraoperatively. This observation is illustrated in Fig. 3 . Two patients were excluded from the study because of loss at follow-up. A total of 37 patients were included in the analysis, all of whom achieved fracture healing during the follow-up period, and none experienced postoperative loss of fracture reduction. In group 1 (n = 15), the anterior pelvic rings of patients were fixed using the INFIX with “barrel handle” connecting rods, with additional fixation of the posterior pelvic rings using S1 screws in seven patients (Fig. 4 ). In group 2 (n = 22), patients underwent INFIX internal fixation of the anterior pelvic rings using circumferential “arc” connecting rods, with concomitant fixation of the posterior pelvic ring using S1 screws in seven patients (Fig. 5 ). There were no significant differences between the two groups regarding sex, age, BMI, ISS, or Tile fracture classification (P > 0.05) (Table 2 ). The postoperative radiographic evaluation of fracture reduction quality revealed comparable satisfaction levels between the two groups (80% versus 77.3%, P = 0.872). The mean duration of follow-up was 14.6 ± 7.7 months for group 1 and 15.7 ± 6.9 months for group 2 (P = 0.554). There was no significant difference between the two groups in the final functional outcome assessed by the Majeed score (90.7 ± 4.6 versus 89.0 ± 5.7, P = 0.974) (Table 3 ). 3.2.1 Complications There was a similar incidence of heterotopic ossification (HO) in group 1 (n = 3, 20%) and group 2 (9.1%, P = 0.341). Notably, all patients with ectopic ossification remained asymptomatic. The incidence of LFCN injury, characterized predominantly by numbness of the anterolateral thigh skin, was lower in group 1 (13.3%, n = 2) than in group 2 (54.5%, n = 12, P = 0.011). Immediate relief of symptoms associated with LFCN injury was reported after removal of the internal fixation device in 64.3% (n = 9) of patients, while gradual resolution within 3 months following internal fixation device removal was experienced by 35% (n = 5) of patients. Postoperative wound infections were significantly more frequent in group 2 (27.3%, n = 6) than in group 1 (0%, n = 0, P = 0.027) (Table 4 ). All patients with wound infections received treatment including anti-infective measures, debridement, and negative pressure wound therapy using vacuum sealing drainage. Unfortunately, none of the infections resolved, necessitating removal of the INFIX at 1 to 2 months after fracture stabilization. Subsequently, complete wound healing was achieved. 4. Discussion The surgical objective for unstable pelvic fractures is to restore the integrity of the pelvic ring, correct deformities, achieve robust fixation, and enable early functional rehabilitation. In 2009, Kuttert et al. introduced the use of a percutaneous anterior pelvic ring fixation system called the nail-rod system, also known as anterior ring percutaneous internal fixation (INFIX). This technique offers several advantages, including technical simplicity, minimal soft tissue trauma, reduced blood loss, and a lower incidence of nerve injury, thereby minimizing common risks associated with open surgery ( 13 ). Extensive research has been conducted on the biomechanics, anatomy, and clinical outcomes of the INFIX system. The findings consistently demonstrate its safety, reliable stability for anterior ring fractures, and satisfactory clinical treatment outcomes ( 14 – 16 ). As the use of the INFIX for unstable pelvic fractures continues to grow, a comprehensive understanding of its associated complications has been obtained. Common complications include HO, LFCN injury, and wound infection. A systematic review and meta-analysis of INFIX internal fixation reported that the incidence of HO was 36.1% (120/332), but the HO was asymptomatic and did not necessitate treatment. LFCN injury or irritation was the most frequently observed complication, affecting 26.3% of patients (123/467), while wound infection occurred in 3% of cases (15/496) [9]. Another systematic review and meta-analysis of INFIX internal fixation revealed that the incidence of HO was 24.7%, the incidence of LFCN complications was 25.3%, and the incidence of infections was 3.1% ( 17 ). Vaidya emphasized the importance of maintaining an adequate distance (15–50 mm) between the screw head and the bone surface to prevent compression of nerves and blood vessels by the connecting rod ( 5 ). However, this requirement gives rise to certain challenges, as detailed below. 1) In Asian individuals, who typically have a slender body habitus, there is a higher risk of the screw head compressing the skin, leading to complications such as wound infection, skin necrosis, and exposed screws. Consequently, the INFIX may be more suitable for patients with obesity ( 5 ). 2) LFCN injury or irritation is a common complication of INFIX treatment of pelvic fracture, with an incidence of up to 26.3% ( 10 ). Surgeons should possess knowledge regarding the insertion point of the screw and the anatomical location of the nerve to minimize the risk of nerve damage during surgery. Furthermore, most patients experience symptom relief or resolution following internal fixation removal, suggesting that the nerve-related issues are related to the INFIX procedure rather than surgical trauma. A cadaveric study demonstrated that the end of the connecting rod is approximately 13.49 ± 1.65 mm from the LFCN, indicating that the end of the rod may directly aggravate the nerve ( 18 ). Another study found that the average distance between the INFIX screws and the anterior cortical margin of the nerve was only 2.2 mm when the pelvis was stabilized ( 19 ). To resolve these issues, we proposed a modification to the connecting rod design of the INFIX, replacing the conventional “arc” with a “barrel handle” shape. This modification allows the screw head to be positioned closer to the bone surface, thereby preventing compression of the surrounding skin and keeping the end of the connecting rod away from the LFCN. The aim of these changes is to reduce the incidence of wound infection, nerve damage, or irritation, making the INFIX safer in slender patients. However, it is essential to assess whether this modification affects the biomechanical stability of fixation with the INFIX. To investigate this, we conducted a comparative study using cadaveric pelvic specimens with different vertical loads. By measuring the displacement of the fracture ends and performing data analysis, we found no significant difference in biomechanical stability between the two designs. Our clinical study included 15 patients in group 1 who had the INFIX connecting rods intraoperatively bent into a “barrel handle” shape and 22 patients in group 2 whose connecting rods were bent into a regular “arc”. There were no significant differences between the two groups in the fracture reduction quality measured by the Matta score and the functional outcome assessed by the Majeed score. Furthermore, the incidence of HO did not differ significantly between the two groups. The incidence of LFCN injury in group 2 was 54.5%, which was significantly more common than in group 1 (13.3%) and is notably higher than the incidence of 25.3% reported by Vaidya et al. ( 10 ). This is likely because our patients had a more slender build than the patients in that study (mean BMI 23.1 ± 3.8 kg/m 2 ), which makes the INFIX connecting rod more likely to damage the LFCN. With the INFIX connecting rod bent into a “barrel handle” shape, the distal end of the connecting rod deviates from the LFCN, reducing the risk of injury and resulting in a significantly lower incidence of LFCN injury in group 1 than in group 2. The incidence of postoperative wound infection in group 2 (27.3%) was significantly higher than in group 1, with no patients in group 1 developing postoperative wound infections. The incidence in group 2 was substantially higher than the incidence of 3% reported by Vaidya et al. ( 10 ). We believe that, in slender patients, the presence of the screw head located directly beneath the skin can lead to compression of the wound area, resulting in delayed wound healing and increased susceptibility to infection. Conversely, in group 1, where the screw head did not compress the skin, there was no incidence of postoperative wound infections. 5. Conclusion INFIX internal fixation has demonstrated favorable clinical outcomes for the management of unstable pelvic fractures. The modified “barrel handle” connecting rod used in the INFIX system provides biomechanical stability that is comparable to that of the conventional “arc” connecting rod. Moreover, the “barrel handle” design significantly reduces the occurrence of postoperative wound infections and anterior exocortical femoral nerve injuries associated with the INFIX procedure. Declarations Ethics approval This study was approved by the Human Subjects Division of the Southern Medical University Review Board. The investigation was performed at the Fifth Affiliated Hospital of Southern Medical University. This work has not been previously presented or published. Informed consent has been obtained from all subjects and/or their legal guardians for the study Availability of data and materials All data generated or analyzed during this study are included in this published article. Competing interests The authors declare that they do not have any competing interests. Funding This work was supported by the National Key Research and Development Project of China: R&D and Demonstration application of key technologies of cloud-integrated visual-audio-touch multi-mode interactive feedback high simulation intelligent virtual surgery (grant no. 2022YFF1202600); President Fund of the Fifth Affiliated Hospital of Southern Medical University: Biomechanical mechanism of in vivo exercise in the diagnosis of pelvic femoral complex fracture classification (YZ2020ZX02); Guangzhou City and Technology Plan Project: Comparison of biomechanical stability of four combined internal fixation methods based on six-degrees-of-freedom of hip joint in the treatment of pelvic C-type fractures (202201011682). Authors’ contributions HC, GW, YL, and HZ conceived and designed the study, and critically revised the manuscript. HC, GW, and SM conducted the experiments and drafted the manuscript. YL, GW, and HC contributed to the analysis and collation of experimental data and the revision of the manuscript. All authors have read and approved the final manuscript. Acknowledgment We thank Kelly Zammit, BVSc, from Liwen Bianji (Edanz) (www.liwenbianji.cn/), for editing the English text of a draft of this manuscript. References Chen W, Lv H, Liu S, Liu B, Zhu Y, Chen X, et al. National incidence of traumatic fractures in China: a retrospective survey of 512 187 individuals. Lancet Glob Health. 2017;5:e807–17. 10.1016/S2214-109X(17)30222-X . Langford JR, Burgess AR, Liporace FA, Haidukewych GJ. Pelvic fractures: part 2. Contemporary indications and techniques for definitive surgical management. J Am Acad Orthop Surg. 2013;21:458–68. 10.5435/JAAOS-21-08-458 . Sagi HC, Papp S. Comparative radiographic and clinical outcome of two-hole and multi-hole symphyseal plating. J Orthop Trauma. 2008;22:373–78. 10.1097/BOT.0b013e31817e49ee . Mason WT, Khan SN, James CL, Chesser TJ, Ward AJ. Complications of temporary and definitive external fixation of pelvic ring injuries. Injury. 2005;36:599–604. 10.1016/j.injury.2004.11.016 . Vaidya R, Colen R, Vigdorchik J, Tonnos F, Sethi A. Treatment of unstable pelvic ring injuries with an internal anterior fixator and posterior fixation: initial clinical series. J Orthop Trauma. 2012;26:1–08. 10.1097/BOT.0b013e318233b8a7 . Vaidya R, Martin AJ, Roth M, Nasr K, Gheraibeh P, Tonnos F. INFIX versus plating for pelvic fractures with disruption of the symphysis pubis. Int Orthop. 2017;41:1671–78. 10.1007/s00264-016-3387-9 . Yin Y, Luo J, Zhang R, Li S, Jiao Z, Zhang Y, et al. Anterior subcutaneous internal fixator (INFIX) versus plate fixation for pelvic anterior ring fracture. Sci Rep. 2019;9:2578. 10.1038/s41598-019-39068-7 . Hoskins W, Bucknill A, Wong J, Britton E, Judson R, Gumm K, et al. A prospective case series for a minimally invasive internal fixation device for anterior pelvic ring fractures. J Orthop Surg Res. 2016;11:135. 10.1186/s13018-016-0468-9 . Shetty AP, Bosco A, Perumal R, Dheenadhayalan J, Rajasekaran S. Midterm radiologic and functional outcomes of minimally-invasive fixation of unstable pelvic fractures using anterior internal fixator(INFIX) and percutaneous iliosacral screws. J Clin Orthop Trauma. 2017;8:241–48. 10.1016/j.jcot.2017.05.009 . Vaidya R, Woodbury D, Nasr K. Anterior Subcutaneous Internal Pelvic Fixation/INFIX: A Systemic Review. J Orthop Trauma. 2018;32(Suppl 6):S24–30. 10.1097/BOT.0000000000001248 . Matta JM, Tornetta PR. Internal fixation of unstable pelvic ring injuries. Clin Orthop Relat Res. 1996;129–40. 10.1097/00003086-199608000-00016 . Majeed SA. Grading the outcome of pelvic fractures. J Bone Joint Surg Br. 1989;71:304–06. 10.1302/0301-620X.71B2.2925751 . Kuttner M, Klaiber A, Lorenz T, Fuchtmeier B, Neugebauer R. [The pelvic subcutaneous cross-over internal fixator]. Unfallchirurg. 2009;112:661–69. 10.1007/s00113-009-1623-0 . Mcdonald E, Theologis AA, Horst P, Kandemir U, Pekmezci M. When do anterior external or internal fixators provide additional stability in an unstable (Tile C) pelvic fracture? A biomechanical study. Eur J Trauma Emerg Surg. 2015;41:665–71. 10.1007/s00068-014-0482-8 . Vaidya R, Martin AJ, Roth M, Tonnos F, Oliphant B, Carlson J. Midterm Radiographic and Functional Outcomes of the Anterior Subcutaneous Internal Pelvic Fixator (INFIX) for Pelvic Ring Injuries. J Orthop Trauma. 2017;31:252–59. 10.1097/BOT.0000000000000781 . Vaidya R. Comment on: The use of anterior subcutaneous internal fixation (INFIX) for treatment of pelvic ring injuries in major trauma patients, complications and outcomes. Sicot J. 2019;5:36. 10.1051/sicotj/2019033 . Kumbhare C, Meena S, Kamboj K, Trikha V. Use of INFIX for managing unstable anterior pelvic ring injuries: A systematic review. J Clin Orthop Trauma. 2020;11:970–75. 10.1016/j.jcot.2020.06.039 . Apivatthakakul T, Rujiwattanapong N. Anterior subcutaneous pelvic internal fixator (INFIX), Is it safe? A cadaveric study. Injury. 2016;47:2077–80. 10.1016/j.injury.2016.08.006 . Reichel LM, MacCormick LM, Dugarte AJ, Rizkala AR, Graves SC, Cole PA. Minimally invasive anterior pelvic internal fixation: An anatomic study comparing Pelvic Bridge to INFIX. Injury. 2018;49:309–14. 10.1016/j.injury.2017.12.009 . Tables Table 1. Comparison of the displacement distance (mm) of the anterior and posterior pelvic rings under 200-800N loading in two groups of specimens Parameter group A（n=8） group B(n=8) P Displacement of anterior pelvic ring 200N 400N 600N 800N Displacement of posterior pelvic ring 200N 400N 600N 800N 0.36±0.11 0.89±0.26 1.21±0.23 1.60±0.22 0.41±0.14 0.74±0.16 0.93±0.23 1.32±0.36 0.48±0.15 0.95±0.25 1.22±0.22 1.64±0.24 0.46±0.11 0.84±0.13 1.21±0.16 1.42±0.18 0.374 0.945 0.555 0.940 0.401 0.681 0.444 0.156 t test Table 2. Patient Demographics of two groups Parameter group 1(n=15) group 2(n=22) P Gender;male/female a 5/10 8/14 0.850 Age b 47.0±17.7 50.4±17.1 0.615 BMI b ISS b Tile class a 21.8±2.6 17.1±5.7 23.1±3.8 15.2±6.2 0.110 0.731 0.661 B1 1 2 B2 3 4 C1 C2 10 1 16 0 a Pearson uncorrected χ2 test b t test Table 3. Postoperative radiology and functional outcome grading group 1(n=15) group 2(n=22) P Tornetta and Matta grading a Excellent Good Fair Poor Statisfactory rate Follow up time(month) b Majeed score b 5 7 3 0 12/15(80%) 14.6±7.7 90.7±4.6 7 10 4 1 17/22（77.3%） 15.7±6.9 89.0±5.7 0.872 0.554 0.974 a Pearson uncorrected χ2 test b t test Table 4. Complications group 1(n=15) group 2(n=22) P Heterotopic ossification a LFCN irritation a Infection a 3 2 0 2 12 6 0.341 0.011 0.027 a Pearson uncorrected χ2 test Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4590388","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":316365977,"identity":"a16a8256-ef15-4031-81bb-a89676a529be","order_by":0,"name":"Hongfen Chen","email":"","orcid":"","institution":"Department of Orthopedics, The Fifth Affiliated Hospital, Southern Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hongfen","middleName":"","lastName":"Chen","suffix":""},{"id":316365978,"identity":"91357359-05b3-49e8-9423-a1d0230aebf8","order_by":1,"name":"Gen Wu","email":"","orcid":"","institution":"Wuhan fourth hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Gen","middleName":"","lastName":"Wu","suffix":""},{"id":316365979,"identity":"5af3d9f8-5b1e-427f-8f4f-406fef4826d4","order_by":2,"name":"Sushuang Ma","email":"","orcid":"","institution":"Southern Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Sushuang","middleName":"","lastName":"Ma","suffix":""},{"id":316365980,"identity":"6838ea42-b617-4224-87bd-e11382760209","order_by":3,"name":"Yanbing Li","email":"","orcid":"","institution":"Southern Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Yanbing","middleName":"","lastName":"Li","suffix":""},{"id":316365981,"identity":"7f894f50-0d53-4f98-b1e6-db1dfa27f637","order_by":4,"name":"Hua Zhong","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0UlEQVRIiWNgGAWjYBAC+xkgskJCjp+9sfHhB2K0MIK1nLExluw53GwsQbQWxra0xA030tsEeIjRwizdfOzhlzOHEzfcfNjGIMFgJ6fbQEALm8yxdGOZisPGM28ntj0oYEg2NjtAQAuPRI6ZtMSZw7J9txPbDSQYDiRuI6RFAqRFsu0wY8PNg20SPMRoMQBqkfzYlqY44QYj0VrS0qQhgZwIDGQDIvxiPyP5mOQPcFQef/jwQ4WdHEEtIMCMiA4DIpSDAOMPIhWOglEwCkbBCAUAU4dF5m4Ey8YAAAAASUVORK5CYII=","orcid":"","institution":"Department of Orthopedics, The Fifth Affiliated Hospital, Southern Medical University","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Hua","middleName":"","lastName":"Zhong","suffix":""}],"badges":[],"createdAt":"2024-06-16 16:02:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4590388/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4590388/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":60448092,"identity":"5e9fda8a-970e-430e-b02e-8b5c732d94db","added_by":"auto","created_at":"2024-07-16 22:11:56","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1120145,"visible":true,"origin":"","legend":"\u003cp\u003e(A-B) Pelvic C1 fracture specimen and schematic diagram, (C-D) pelvic C1 fracture specimen fixed with “barrel handle” connecting rod and schematic diagram, (E-F) pelvic C1 fracture specimen fixed with “arc-shaped” connecting rod and schematic diagram.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4590388/v1/50db33c75c9f1f8e103a6baa.jpg"},{"id":60447544,"identity":"04bea335-5da5-42bd-8d55-ede43dfc9074","added_by":"auto","created_at":"2024-07-16 22:03:56","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":387859,"visible":true,"origin":"","legend":"\u003cp\u003e(A) Pressure was applied to the specimen using a biomechanical testingmachine, and (B) displacement of the fracture end under different pressures was measured using vernier calipers.\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4590388/v1/2fade4f8ddcbf61e55d8ddb6.jpg"},{"id":60447541,"identity":"45d10dc3-d65c-4089-afcc-cf6bcc580ae2","added_by":"auto","created_at":"2024-07-16 22:03:56","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":600687,"visible":true,"origin":"","legend":"\u003cp\u003eIncision by two surgical methods. (A-B) INFIX fixation with “arc” connecting rods; screw was close to the patient's skin and wound healing was difficult. (C-D) INFIX fixation with barrel handle connecting rods, with screws distant from the skin.\u003c/p\u003e","description":"","filename":"Figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4590388/v1/8771d06b212898e780c917a6.jpg"},{"id":60448892,"identity":"012e8e58-ddbf-4b53-965b-f11404d3c3db","added_by":"auto","created_at":"2024-07-16 22:19:56","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":2804074,"visible":true,"origin":"","legend":"\u003cp\u003eImage of the patient after INFIX fixation with a “barrel handle” rod. (A) Pelvic C1 fracture X-ray, (B) CT three-dimensional reconstruction of pelvic C1 fracture. (C-E) Anteroposterior, inlet, and outlet radiographs of the pelvis after INFIX fixation using a “barrel handle” rod. (F) Anteroposterior pelvic radiograph at 3 months postoperatively.\u003c/p\u003e","description":"","filename":"Figure4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4590388/v1/71d867579178d9490a92fada.jpg"},{"id":60447546,"identity":"05e3f098-7f11-484f-862d-90124e71ad43","added_by":"auto","created_at":"2024-07-16 22:03:56","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":3910798,"visible":true,"origin":"","legend":"\u003cp\u003eImage of patient after INFIX fixation with “arc” connecting rods. (A) X-ray of pelvic C1 fracture, (B) CT three-dimensional reconstruction of pelvic C1 fracture. (C-E) Anteroposterior, inlet, and outlet radiographs of the pelvis after INFIX fixation with “arc”connecting rods. (F) Anteroposterior pelvic radiograph at 3 months postoperatively.\u003c/p\u003e","description":"","filename":"Figure5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4590388/v1/3bbed2f1764dcf9d11da8313.jpg"},{"id":98774558,"identity":"07e7fc35-4eff-4e96-954a-3a19d909957a","added_by":"auto","created_at":"2025-12-22 12:00:02","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":9472015,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4590388/v1/c7dda26c-2534-4396-a5e9-9936fa2f6895.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Biomechanics and clinical outcomes of “barrel handle” connecting rods used in INFIX internal fixation for unstable pelvic fractures: a cadaveric biomechanical study and retrospective cohort study","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eUnstable pelvic fractures most often occur in association with high-energy injuries. Although their incidence is low, accounting for approximately 1.5\u0026ndash;3.9% of all fractures, unstable pelvic fractures are characterized by high rates of disability and mortality (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Early surgical intervention has been underscored in various studies for its pivotal role in pain management, facilitation of early mobility, and prevention of chronic pelvic instability and resultant disability(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTraditional approaches for treating pelvic fractures include open reduction with internal plate fixation or external fixators. However, these methods carry risks of vascular and nerve injury, as well as inguinal hernia (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). External fixation frames are primarily used for emergency injury control to stabilize unstable pelvic fractures and promptly restore hemodynamic stability. However, the common complications of external fixation are postoperative nail tract infection, failure of external fixation, and restricted joint movement due to the presence of external fixation frames (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe anterior subcutaneous internal fixator (INFIX) is increasingly being used to treat unstable pelvic fractures because of its advantages over previous pelvic fixation techniques, including a shorter surgery time, reduced bleeding, lower infection rates, and faster recovery (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). However, the incidence of lateral femoral cutaneous nerve injury or irritation following internal fixation with the INFIX with the \u0026ldquo;arc\u0026rdquo; connecting rod is as high as 26.3%. Most patients experience symptom relief or resolution after removal of the internal fixation, indicating that this nerve injury is not a result of surgical injury, but rather is associated with the INFIX itself (\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eBecause of the generally slender and small size of the Asian body, pelvic fixation with the INFIX may pose a higher risk of anterolateral femoral cutaneous nerve (LFCN) injury in Asian patients than in patients in Western countries. Additionally, the screw head may exert pressure on the skin, leading to wound infection, skin necrosis, exposure of the INFIX, and subsequent complications. To address these concerns, we modified the shape of the connecting rod by bending it into a \u0026ldquo;barrel handle\u0026rdquo; configuration. We then evaluated the biomechanical stability of the INFIX with the \u0026ldquo;barrel handle\u0026rdquo; connecting rod and compared the clinical effects of pelvic fixation with the INFIX with the \u0026ldquo;barrel handle\u0026rdquo; connecting rod versus the INFIX with the \u0026ldquo;arc\u0026rdquo; connecting rod.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 In vitro experiments\u003c/h2\u003e \u003cdiv id=\"Sec4\" class=\"Section3\"\u003e \u003ch2\u003e2.1.1 Materials\u003c/h2\u003e \u003cp\u003eSixteen adult pelvic specimens (from 9 males and 7 females) were embalmed prior to biomechanical testing. These pelvic specimens are all from body donations. In each specimen, the femur was preserved at a length of approximately 15 cm, while the lumbar spine was preserved to the fifth lumbar vertebra (L5). The soft tissues were removed, and the anterior and posterior sacroiliac ligaments, sacral spines, and sacral tubercle ligaments were preserved. Additionally, all ligamentous attachments from L5 to the pelvis were preserved. All pelvic specimens were radiographed to exclude the presence of tumors, tuberculosis, osteoporosis, or other diseases. The specimens were stored at \u0026minus;\u0026thinsp;30\u0026deg;C.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e2.1.2 Operation\u003c/h2\u003e \u003cp\u003eA fracture line with a 2.0-mm gap was created on the upper and lower branches of the pubic bone on one side using an electric pendulum saw. The sacrum was vertically cut ipsilaterally through the Denis 2 zone, and the fracture line was maintained with a 2.0 mm gap to create a Tile C1 type unstable pelvic fracture model. All specimens were prepared by the same operator (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA, \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB). The model specimens were randomly divided into groups A and B, each consisting of eight specimens.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eSacroiliac fixation (n\u0026thinsp;=\u0026thinsp;16): a single 7.3 mm \u0026times; 90 mm hollow screw (Synthes) was used to fixate S1, ensuring that the screw passed through the sacroiliac joint and the fracture site, and crossed the midline of the S1 vertebral body after being inserted from the iliac bone.\u003c/p\u003e \u003cp\u003eGroup A (n\u0026thinsp;=\u0026thinsp;8): two 6.5 mm \u0026times; 70 mm multiaxial pedicle screws (Synthes Company) were inserted through the plane of the bilateral anterior and inferior iliac spines. The screw heads contacted the bone surface, and the 6-mm INFIX connecting rod (Synthes Company) was bent into a \u0026ldquo;barrel handle\u0026rdquo; shape for connection and fixation (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eC, \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eD).\u003c/p\u003e \u003cp\u003eGroup B (n\u0026thinsp;=\u0026thinsp;8): two 6.5 mm \u0026times; 70 mm multiaxial pedicle screws (Synthes) were inserted through the plane of the bilateral anterior and inferior iliac spines. The distance between the screw heads and the bone surface was approximately 2 cm, and the 6-mm INFIX connecting rods (Synthes) were bent into an \u0026ldquo;arc\u0026rdquo; shape and fixed.\u003c/p\u003e \u003cp\u003eOne Kirschner needle was inserted on each side of the pubic ramus and sacral fractures in all specimens, and the horizontal and vertical displacement values between the two Kirschner needles were measured and recorded during pelvic compression (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eE, \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eF).\u003c/p\u003e \u003cp\u003eThe L5 vertebral body and distal bilateral femur in all specimens were immobilized using self-coagulating dental tray powder resin and mounted onto the Electroforce 3510 biomechanical testing machine (Ph.D., USA) for assessment (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). A loading speed of 20 N/s was applied to induce axial compression at the upper sacral base. The distance between the pubic branch and the Kirschner needle at the sacral fracture endpoint was recorded at loads of 200 N, 400 N, 600 N, and 800 N. The resulting distances represented the displacements of the fracture ends.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Cases\u003c/h2\u003e \u003cp\u003eThe retrospective cohort study evaluated 37 patients with unstable pelvic fractures who were admitted to the Trauma Center of the Fifth Affiliated Hospital of Southern Medical University between September 2020 and October 2022. Patients younger than 18 years and those with pathological fractures were excluded from the study. Prior to undergoing surgery, all patients underwent comprehensive imaging evaluations, including pelvic radiography (anteroposterior, inlet, and outlet views) and computed tomography. Two experienced orthopedic surgeons independently reviewed the imaging data and used the Tile pelvic fracture classification criteria to categorize each fracture. Patient-specific details, such as sex, age, body mass index (BMI), Injury Severity Score (ISS), Tile fracture classification, and follow-up duration, were meticulously recorded. Postoperative outcomes were assessed based on radiological fracture evaluation, functional scoring, and the occurrence of complications such as ectopic ossification, anterior exocutaneous nerve injury, and wound infection.\u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.2.1 Operation\u003c/h2\u003e \u003cp\u003eThe patients were positioned in a supine position on a fluoroscopic operating table and received conventional anesthesia. In cases where there was injury and instability of the posterior pelvic ring requiring internal fixation, screw fixation was performed as the primary intervention.\u003c/p\u003e \u003cp\u003eA standardized surgical approach was used for all patients, commencing with a 3-cm oblique incision at the anterior superior iliac spine. Subsequently, meticulous dissection was carried out within the interfascial plane separating the tensor fascia lata and sartorius muscles. A pedicle screw detector was used to perform precise screw placement in the iliac bone between the inner and outer cortical plates, while precautions were taken to ensure that there was no breach through the bone cortex. Two multiaxial pedicle screws (6.5 mm diameter, 70 mm length) were meticulously inserted. A 6-mm-diameter titanium rod, tailored to the appropriate length, was contoured into either a \u0026ldquo;barrel handle\u0026rdquo; or an \u0026ldquo;arc\u0026rdquo; configuration, depending on the assigned fixation group. Subsequently, a subcutaneous tunnel was created to connect and secure the bilateral pedicle screws with the contoured rod. In the group treated with the INFIX with the \u0026ldquo;barrel handle\u0026rdquo; connecting rod (group 1), the pedicle screw heads were in direct contact with the bone surface. In the group treated with the INFIX with the \u0026ldquo;arc-shaped\u0026rdquo; connecting rod (group 2), a minimum distance of 2 cm was maintained between the pedicle screw heads and the bone surface to minimize the risk of nerve and vascular compression caused by the connecting rod.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.2.2 Assessment of fracture reduction quality\u003c/h2\u003e \u003cp\u003ePostoperatively, the reduction quality for anterior pelvic ring fractures was immediately assessed by measuring the maximum displacement distance of the fracture on anteroposterior, inlet, and outlet radiographs. The evaluation criteria used in this study followed the classification system introduced by Tornetta and Matta (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). Fracture displacement distances were classified as preferred (\u0026lt;\u0026thinsp;4 mm), good (5\u0026ndash;10 mm), acceptable (10\u0026ndash;20 mm), and poor (\u0026gt;\u0026thinsp;20 mm). For the purpose of this study, fracture reduction was regarded as satisfactory if the displacement distance was categorized as preferred or good.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.2.3 Postoperative management and follow-up\u003c/h2\u003e \u003cp\u003eDuring the postoperative period, patients were strongly encouraged to initiate early lower extremity exercises, within tolerable pain limits, to mitigate the risk of deep vein thrombosis. Partial weightbearing was typically initiated 1 month after surgery for Tile B fractures, and 2 months after surgery for Tile C fractures; the initiation of partial weightbearing was contingent upon radiographic confirmation of complete fracture consolidation.\u003c/p\u003e \u003cp\u003ePostoperative functional assessment was performed in accordance with the Majeed scale (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). Patient follow-up was conducted via telephonic interviews or outpatient consultations. During the final follow-up visit, patients were requested to complete the Majeed score questionnaire, which encompassed domains such as pain, work functionality, sitting ability, sexual intercourse, standing capacity, walking distance, and gait. The Majeed score was categorized into four grades: excellent (\u0026gt;\u0026thinsp;85), good (70\u0026ndash;84), fair (55\u0026ndash;69), and poor (\u0026lt;\u0026thinsp;55).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.2.4 Statistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was conducted using IBM SPSS Statistics for Windows, version 23.0 (Armonk, NY, USA). The t-test and Pearson's chi-squared test were used as the statistical methods. P values lower than 0.05 were deemed to indicate statistically significant differences.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\n \u003ch2\u003e3.1 Specimen experiments\u003c/h2\u003e\n \u003cp\u003eNone of the specimens exhibited failure when subjected to a load of 800 N. The average displacement distances of the fractured ends in both the anterior and posterior pelvic rings in the two groups under various loads are summarized in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. The results demonstrate an increasing trend in fracture displacement distances with greater loads. When the same loads were compared, group A displayed relatively smaller average displacement distances than group B. However, statistical analysis revealed no significant differences between the two groups (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\n \u003ch2\u003e3.2 Clinical cases\u003c/h2\u003e\n \u003cp\u003eGroup 2 patients (INFIX with \u0026ldquo;arc\u0026rdquo; connecting rods) exhibited postoperative screw exposure, while the screws in group 1 patients (INFIX with \u0026ldquo;barrel handle\u0026rdquo; connecting rods) were visually remote from the skin intraoperatively. This observation is illustrated in Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e\n \u003cp\u003eTwo patients were excluded from the study because of loss at follow-up. A total of 37 patients were included in the analysis, all of whom achieved fracture healing during the follow-up period, and none experienced postoperative loss of fracture reduction. In group 1 (n\u0026thinsp;=\u0026thinsp;15), the anterior pelvic rings of patients were fixed using the INFIX with \u0026ldquo;barrel handle\u0026rdquo; connecting rods, with additional fixation of the posterior pelvic rings using S1 screws in seven patients (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e). In group 2 (n\u0026thinsp;=\u0026thinsp;22), patients underwent INFIX internal fixation of the anterior pelvic rings using circumferential \u0026ldquo;arc\u0026rdquo; connecting rods, with concomitant fixation of the posterior pelvic ring using S1 screws in seven patients (Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e). There were no significant differences between the two groups regarding sex, age, BMI, ISS, or Tile fracture classification (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). The postoperative radiographic evaluation of fracture reduction quality revealed comparable satisfaction levels between the two groups (80% versus 77.3%, P\u0026thinsp;=\u0026thinsp;0.872). The mean duration of follow-up was 14.6\u0026thinsp;\u0026plusmn;\u0026thinsp;7.7 months for group 1 and 15.7\u0026thinsp;\u0026plusmn;\u0026thinsp;6.9 months for group 2 (P\u0026thinsp;=\u0026thinsp;0.554). There was no significant difference between the two groups in the final functional outcome assessed by the Majeed score (90.7\u0026thinsp;\u0026plusmn;\u0026thinsp;4.6 versus 89.0\u0026thinsp;\u0026plusmn;\u0026thinsp;5.7, P\u0026thinsp;=\u0026thinsp;0.974) (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e\n \u003ch2\u003e3.2.1 Complications\u003c/h2\u003e\n \u003cp\u003eThere was a similar incidence of heterotopic ossification (HO) in group 1 (n\u0026thinsp;=\u0026thinsp;3, 20%) and group 2 (9.1%, P\u0026thinsp;=\u0026thinsp;0.341). Notably, all patients with ectopic ossification remained asymptomatic. The incidence of LFCN injury, characterized predominantly by numbness of the anterolateral thigh skin, was lower in group 1 (13.3%, n\u0026thinsp;=\u0026thinsp;2) than in group 2 (54.5%, n\u0026thinsp;=\u0026thinsp;12, P\u0026thinsp;=\u0026thinsp;0.011). Immediate relief of symptoms associated with LFCN injury was reported after removal of the internal fixation device in 64.3% (n\u0026thinsp;=\u0026thinsp;9) of patients, while gradual resolution within 3 months following internal fixation device removal was experienced by 35% (n\u0026thinsp;=\u0026thinsp;5) of patients. Postoperative wound infections were significantly more frequent in group 2 (27.3%, n\u0026thinsp;=\u0026thinsp;6) than in group 1 (0%, n\u0026thinsp;=\u0026thinsp;0, P\u0026thinsp;=\u0026thinsp;0.027) (Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e). All patients with wound infections received treatment including anti-infective measures, debridement, and negative pressure wound therapy using vacuum sealing drainage. Unfortunately, none of the infections resolved, necessitating removal of the INFIX at 1 to 2 months after fracture stabilization. Subsequently, complete wound healing was achieved.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe surgical objective for unstable pelvic fractures is to restore the integrity of the pelvic ring, correct deformities, achieve robust fixation, and enable early functional rehabilitation. In 2009, Kuttert et al. introduced the use of a percutaneous anterior pelvic ring fixation system called the nail-rod system, also known as anterior ring percutaneous internal fixation (INFIX). This technique offers several advantages, including technical simplicity, minimal soft tissue trauma, reduced blood loss, and a lower incidence of nerve injury, thereby minimizing common risks associated with open surgery (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). Extensive research has been conducted on the biomechanics, anatomy, and clinical outcomes of the INFIX system. The findings consistently demonstrate its safety, reliable stability for anterior ring fractures, and satisfactory clinical treatment outcomes (\u003cspan additionalcitationids=\"CR15\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAs the use of the INFIX for unstable pelvic fractures continues to grow, a comprehensive understanding of its associated complications has been obtained. Common complications include HO, LFCN injury, and wound infection. A systematic review and meta-analysis of INFIX internal fixation reported that the incidence of HO was 36.1% (120/332), but the HO was asymptomatic and did not necessitate treatment. LFCN injury or irritation was the most frequently observed complication, affecting 26.3% of patients (123/467), while wound infection occurred in 3% of cases (15/496) [9]. Another systematic review and meta-analysis of INFIX internal fixation revealed that the incidence of HO was 24.7%, the incidence of LFCN complications was 25.3%, and the incidence of infections was 3.1% (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eVaidya emphasized the importance of maintaining an adequate distance (15\u0026ndash;50 mm) between the screw head and the bone surface to prevent compression of nerves and blood vessels by the connecting rod (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). However, this requirement gives rise to certain challenges, as detailed below.\u003c/p\u003e \u003cp\u003e1) In Asian individuals, who typically have a slender body habitus, there is a higher risk of the screw head compressing the skin, leading to complications such as wound infection, skin necrosis, and exposed screws. Consequently, the INFIX may be more suitable for patients with obesity (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e2) LFCN injury or irritation is a common complication of INFIX treatment of pelvic fracture, with an incidence of up to 26.3% (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Surgeons should possess knowledge regarding the insertion point of the screw and the anatomical location of the nerve to minimize the risk of nerve damage during surgery. Furthermore, most patients experience symptom relief or resolution following internal fixation removal, suggesting that the nerve-related issues are related to the INFIX procedure rather than surgical trauma. A cadaveric study demonstrated that the end of the connecting rod is approximately 13.49\u0026thinsp;\u0026plusmn;\u0026thinsp;1.65 mm from the LFCN, indicating that the end of the rod may directly aggravate the nerve (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). Another study found that the average distance between the INFIX screws and the anterior cortical margin of the nerve was only 2.2 mm when the pelvis was stabilized (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTo resolve these issues, we proposed a modification to the connecting rod design of the INFIX, replacing the conventional \u0026ldquo;arc\u0026rdquo; with a \u0026ldquo;barrel handle\u0026rdquo; shape. This modification allows the screw head to be positioned closer to the bone surface, thereby preventing compression of the surrounding skin and keeping the end of the connecting rod away from the LFCN. The aim of these changes is to reduce the incidence of wound infection, nerve damage, or irritation, making the INFIX safer in slender patients. However, it is essential to assess whether this modification affects the biomechanical stability of fixation with the INFIX. To investigate this, we conducted a comparative study using cadaveric pelvic specimens with different vertical loads. By measuring the displacement of the fracture ends and performing data analysis, we found no significant difference in biomechanical stability between the two designs.\u003c/p\u003e \u003cp\u003eOur clinical study included 15 patients in group 1 who had the INFIX connecting rods intraoperatively bent into a \u0026ldquo;barrel handle\u0026rdquo; shape and 22 patients in group 2 whose connecting rods were bent into a regular \u0026ldquo;arc\u0026rdquo;. There were no significant differences between the two groups in the fracture reduction quality measured by the Matta score and the functional outcome assessed by the Majeed score. Furthermore, the incidence of HO did not differ significantly between the two groups.\u003c/p\u003e \u003cp\u003eThe incidence of LFCN injury in group 2 was 54.5%, which was significantly more common than in group 1 (13.3%) and is notably higher than the incidence of 25.3% reported by Vaidya et al. (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). This is likely because our patients had a more slender build than the patients in that study (mean BMI 23.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8 kg/m\u003csup\u003e2\u003c/sup\u003e), which makes the INFIX connecting rod more likely to damage the LFCN. With the INFIX connecting rod bent into a \u0026ldquo;barrel handle\u0026rdquo; shape, the distal end of the connecting rod deviates from the LFCN, reducing the risk of injury and resulting in a significantly lower incidence of LFCN injury in group 1 than in group 2.\u003c/p\u003e \u003cp\u003eThe incidence of postoperative wound infection in group 2 (27.3%) was significantly higher than in group 1, with no patients in group 1 developing postoperative wound infections. The incidence in group 2 was substantially higher than the incidence of 3% reported by Vaidya et al. (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). We believe that, in slender patients, the presence of the screw head located directly beneath the skin can lead to compression of the wound area, resulting in delayed wound healing and increased susceptibility to infection. Conversely, in group 1, where the screw head did not compress the skin, there was no incidence of postoperative wound infections.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eINFIX internal fixation has demonstrated favorable clinical outcomes for the management of unstable pelvic fractures. The modified \u0026ldquo;barrel handle\u0026rdquo; connecting rod used in the INFIX system provides biomechanical stability that is comparable to that of the conventional \u0026ldquo;arc\u0026rdquo; connecting rod. Moreover, the \u0026ldquo;barrel handle\u0026rdquo; design significantly reduces the occurrence of postoperative wound infections and anterior exocortical femoral nerve injuries associated with the INFIX procedure.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Human Subjects Division of the Southern Medical University Review Board. The investigation was performed at the Fifth Affiliated Hospital of Southern Medical University.\u003c/p\u003e\n\u003cp\u003eThis work has not been previously presented or published.\u003c/p\u003e\n\u003cp\u003eInformed consent has been obtained from all subjects and/or their legal guardians for the study\u003c/p\u003e\n\u003ch4\u003eAvailability of data and materials\u003c/h4\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in this published article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they do not have any competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the National\u0026nbsp;Key Research and Development Project of\u0026nbsp;China: R\u0026amp;D and Demonstration application of key technologies of cloud-integrated visual-audio-touch multi-mode interactive feedback high simulation intelligent virtual surgery (grant no.\u0026nbsp;2022YFF1202600); President Fund of the Fifth Affiliated Hospital of Southern Medical University: Biomechanical mechanism of in vivo exercise in the diagnosis of pelvic femoral complex fracture classification (YZ2020ZX02); Guangzhou City and Technology Plan Project: Comparison of biomechanical stability of four combined internal fixation methods based on six-degrees-of-freedom of hip joint in the treatment of pelvic C-type fractures (202201011682).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHC, GW, YL, and HZ conceived and designed the study, and critically revised the manuscript. HC, GW, and SM conducted the experiments and drafted the manuscript. YL, GW, and HC contributed to the analysis and collation of experimental data and the revision of the manuscript. All authors have read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank Kelly Zammit, BVSc, from Liwen Bianji (Edanz) (www.liwenbianji.cn/), for editing the English text of a draft of this manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eChen W, Lv H, Liu S, Liu B, Zhu Y, Chen X, et al. National incidence of traumatic fractures in China: a retrospective survey of 512 187 individuals. Lancet Glob Health. 2017;5:e807\u0026ndash;17. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S2214-109X(17)30222-X\u003c/span\u003e\u003cspan address=\"10.1016/S2214-109X(17)30222-X\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLangford JR, Burgess AR, Liporace FA, Haidukewych GJ. Pelvic fractures: part 2. Contemporary indications and techniques for definitive surgical management. J Am Acad Orthop Surg. 2013;21:458\u0026ndash;68. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.5435/JAAOS-21-08-458\u003c/span\u003e\u003cspan address=\"10.5435/JAAOS-21-08-458\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSagi HC, Papp S. Comparative radiographic and clinical outcome of two-hole and multi-hole symphyseal plating. J Orthop Trauma. 2008;22:373\u0026ndash;78. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/BOT.0b013e31817e49ee\u003c/span\u003e\u003cspan address=\"10.1097/BOT.0b013e31817e49ee\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMason WT, Khan SN, James CL, Chesser TJ, Ward AJ. Complications of temporary and definitive external fixation of pelvic ring injuries. Injury. 2005;36:599\u0026ndash;604. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.injury.2004.11.016\u003c/span\u003e\u003cspan address=\"10.1016/j.injury.2004.11.016\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVaidya R, Colen R, Vigdorchik J, Tonnos F, Sethi A. Treatment of unstable pelvic ring injuries with an internal anterior fixator and posterior fixation: initial clinical series. J Orthop Trauma. 2012;26:1\u0026ndash;08. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/BOT.0b013e318233b8a7\u003c/span\u003e\u003cspan address=\"10.1097/BOT.0b013e318233b8a7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVaidya R, Martin AJ, Roth M, Nasr K, Gheraibeh P, Tonnos F. INFIX versus plating for pelvic fractures with disruption of the symphysis pubis. Int Orthop. 2017;41:1671\u0026ndash;78. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00264-016-3387-9\u003c/span\u003e\u003cspan address=\"10.1007/s00264-016-3387-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYin Y, Luo J, Zhang R, Li S, Jiao Z, Zhang Y, et al. Anterior subcutaneous internal fixator (INFIX) versus plate fixation for pelvic anterior ring fracture. Sci Rep. 2019;9:2578. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1038/s41598-019-39068-7\u003c/span\u003e\u003cspan address=\"10.1038/s41598-019-39068-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHoskins W, Bucknill A, Wong J, Britton E, Judson R, Gumm K, et al. A prospective case series for a minimally invasive internal fixation device for anterior pelvic ring fractures. J Orthop Surg Res. 2016;11:135. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s13018-016-0468-9\u003c/span\u003e\u003cspan address=\"10.1186/s13018-016-0468-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShetty AP, Bosco A, Perumal R, Dheenadhayalan J, Rajasekaran S. Midterm radiologic and functional outcomes of minimally-invasive fixation of unstable pelvic fractures using anterior internal fixator(INFIX) and percutaneous iliosacral screws. J Clin Orthop Trauma. 2017;8:241\u0026ndash;48. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jcot.2017.05.009\u003c/span\u003e\u003cspan address=\"10.1016/j.jcot.2017.05.009\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVaidya R, Woodbury D, Nasr K. Anterior Subcutaneous Internal Pelvic Fixation/INFIX: A Systemic Review. J Orthop Trauma. 2018;32(Suppl 6):S24\u0026ndash;30. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/BOT.0000000000001248\u003c/span\u003e\u003cspan address=\"10.1097/BOT.0000000000001248\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMatta JM, Tornetta PR. Internal fixation of unstable pelvic ring injuries. Clin Orthop Relat Res. 1996;129\u0026ndash;40. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/00003086-199608000-00016\u003c/span\u003e\u003cspan address=\"10.1097/00003086-199608000-00016\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMajeed SA. Grading the outcome of pelvic fractures. J Bone Joint Surg Br. 1989;71:304\u0026ndash;06. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1302/0301-620X.71B2.2925751\u003c/span\u003e\u003cspan address=\"10.1302/0301-620X.71B2.2925751\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKuttner M, Klaiber A, Lorenz T, Fuchtmeier B, Neugebauer R. [The pelvic subcutaneous cross-over internal fixator]. Unfallchirurg. 2009;112:661\u0026ndash;69. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00113-009-1623-0\u003c/span\u003e\u003cspan address=\"10.1007/s00113-009-1623-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcdonald E, Theologis AA, Horst P, Kandemir U, Pekmezci M. When do anterior external or internal fixators provide additional stability in an unstable (Tile C) pelvic fracture? A biomechanical study. Eur J Trauma Emerg Surg. 2015;41:665\u0026ndash;71. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00068-014-0482-8\u003c/span\u003e\u003cspan address=\"10.1007/s00068-014-0482-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVaidya R, Martin AJ, Roth M, Tonnos F, Oliphant B, Carlson J. Midterm Radiographic and Functional Outcomes of the Anterior Subcutaneous Internal Pelvic Fixator (INFIX) for Pelvic Ring Injuries. J Orthop Trauma. 2017;31:252\u0026ndash;59. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/BOT.0000000000000781\u003c/span\u003e\u003cspan address=\"10.1097/BOT.0000000000000781\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVaidya R. Comment on: The use of anterior subcutaneous internal fixation (INFIX) for treatment of pelvic ring injuries in major trauma patients, complications and outcomes. Sicot J. 2019;5:36. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1051/sicotj/2019033\u003c/span\u003e\u003cspan address=\"10.1051/sicotj/2019033\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKumbhare C, Meena S, Kamboj K, Trikha V. Use of INFIX for managing unstable anterior pelvic ring injuries: A systematic review. J Clin Orthop Trauma. 2020;11:970\u0026ndash;75. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jcot.2020.06.039\u003c/span\u003e\u003cspan address=\"10.1016/j.jcot.2020.06.039\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eApivatthakakul T, Rujiwattanapong N. Anterior subcutaneous pelvic internal fixator (INFIX), Is it safe? A cadaveric study. Injury. 2016;47:2077\u0026ndash;80. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.injury.2016.08.006\u003c/span\u003e\u003cspan address=\"10.1016/j.injury.2016.08.006\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReichel LM, MacCormick LM, Dugarte AJ, Rizkala AR, Graves SC, Cole PA. Minimally invasive anterior pelvic internal fixation: An anatomic study comparing Pelvic Bridge to INFIX. Injury. 2018;49:309\u0026ndash;14. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.injury.2017.12.009\u003c/span\u003e\u003cspan address=\"10.1016/j.injury.2017.12.009\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e\u0026nbsp; Comparison of the displacement distance (mm) of the anterior and posterior pelvic rings under 200-800N loading in two groups of specimens\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.82640144665461%\" valign=\"top\"\u003e\n \u003cp\u003eParameter\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.49728752260398%\" valign=\"top\"\u003e\n \u003cp\u003egroup A（n=8）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.95479204339964%\" valign=\"top\" style=\"width: 24.9006%;\"\u003e\n \u003cp\u003egroup B(n=8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.72151898734177%\" valign=\"top\" style=\"width: 17.7484%;\"\u003e\n \u003cp\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.82640144665461%\" valign=\"top\"\u003e\n \u003cp\u003eDisplacement of anterior pelvic ring\u003c/p\u003e\n \u003cp\u003e200N\u003c/p\u003e\n \u003cp\u003e400N\u003c/p\u003e\n \u003cp\u003e600N\u003c/p\u003e\n \u003cp\u003e800N\u003c/p\u003e\n \u003cp\u003eDisplacement of posterior pelvic ring\u003c/p\u003e\n \u003cp\u003e200N\u003c/p\u003e\n \u003cp\u003e400N\u003c/p\u003e\n \u003cp\u003e600N\u003c/p\u003e\n \u003cp\u003e800N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.49728752260398%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.36\u0026plusmn;0.11\u003c/p\u003e\n \u003cp\u003e0.89\u0026plusmn;0.26\u003c/p\u003e\n \u003cp\u003e1.21\u0026plusmn;0.23\u003c/p\u003e\n \u003cp\u003e1.60\u0026plusmn;0.22\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.41\u0026plusmn;0.14\u003c/p\u003e\n \u003cp\u003e0.74\u0026plusmn;0.16\u003c/p\u003e\n \u003cp\u003e0.93\u0026plusmn;0.23\u003c/p\u003e\n \u003cp\u003e1.32\u0026plusmn;0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.95479204339964%\" valign=\"top\" style=\"width: 24.9006%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.48\u0026plusmn;0.15\u003c/p\u003e\n \u003cp\u003e0.95\u0026plusmn;0.25\u003c/p\u003e\n \u003cp\u003e1.22\u0026plusmn;0.22\u003c/p\u003e\n \u003cp\u003e1.64\u0026plusmn;0.24\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.46\u0026plusmn;0.11\u003c/p\u003e\n \u003cp\u003e0.84\u0026plusmn;0.13\u003c/p\u003e\n \u003cp\u003e1.21\u0026plusmn;0.16\u003c/p\u003e\n \u003cp\u003e1.42\u0026plusmn;0.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.72151898734177%\" valign=\"top\" style=\"width: 17.7484%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.374\u003c/p\u003e\n \u003cp\u003e0.945\u003c/p\u003e\n \u003cp\u003e0.555\u003c/p\u003e\n \u003cp\u003e0.940\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.401\u003c/p\u003e\n \u003cp\u003e0.681\u003c/p\u003e\n \u003cp\u003e0.444\u003c/p\u003e\n \u003cp\u003e0.156\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003et test\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 2.\u003c/strong\u003e Patient Demographics of two groups\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.36823104693141%\" valign=\"top\"\u003e\n \u003cp\u003eParameter\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.812274368231048%\" valign=\"top\"\u003e\n \u003cp\u003egroup 1(n=15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.075812274368232%\" valign=\"top\"\u003e\n \u003cp\u003egroup 2(n=22)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.743682310469314%\" valign=\"top\"\u003e\n \u003cp\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.36823104693141%\" valign=\"top\"\u003e\n \u003cp\u003eGender;male/female\u003csup\u003ea\u003c/sup\u003e\u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.812274368231048%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;5/10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.075812274368232%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; 8/14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.743682310469314%\" valign=\"top\"\u003e\n \u003cp\u003e0.850\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.36823104693141%\" valign=\"top\"\u003e\n \u003cp\u003eAge\u003csup\u003eb\u003c/sup\u003e \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.812274368231048%\" valign=\"top\"\u003e\n \u003cp\u003e47.0\u0026plusmn;17.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.075812274368232%\" valign=\"top\"\u003e\n \u003cp\u003e50.4\u0026plusmn;17.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.743682310469314%\" valign=\"top\"\u003e\n \u003cp\u003e0.615\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.36823104693141%\" valign=\"top\"\u003e\n \u003cp\u003eBMI\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;ISS\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eTile class\u003csup\u003ea\u003c/sup\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.812274368231048%\" valign=\"top\"\u003e\n \u003cp\u003e21.8\u0026plusmn;2.6\u003c/p\u003e\n \u003cp\u003e17.1\u0026plusmn;5.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.075812274368232%\" valign=\"top\"\u003e\n \u003cp\u003e23.1\u0026plusmn;3.8\u003c/p\u003e\n \u003cp\u003e15.2\u0026plusmn;6.2\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.743682310469314%\" valign=\"top\"\u003e\n \u003cp\u003e0.110\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; 0.731\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;0.661\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.36823104693141%\" valign=\"top\"\u003e\n \u003cp\u003eB1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.812274368231048%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.075812274368232%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.743682310469314%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.36823104693141%\" valign=\"top\"\u003e\n \u003cp\u003eB2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.812274368231048%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.075812274368232%\" valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.743682310469314%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.36823104693141%\" valign=\"top\"\u003e\n \u003cp\u003eC1\u003c/p\u003e\n \u003cp\u003eC2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.812274368231048%\" valign=\"top\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.075812274368232%\" valign=\"top\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.743682310469314%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003csup\u003ea\u003c/sup\u003ePearson uncorrected \u0026chi;2 test \u0026nbsp;\u003csup\u003e\u0026nbsp;b\u0026nbsp;\u003c/sup\u003et test\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3.\u0026nbsp;\u003c/strong\u003ePostoperative radiology and functional outcome grading\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.71171171171171%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.36036036036036%\" valign=\"top\"\u003e\n \u003cp\u003egroup 1(n=15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.405405405405407%\" valign=\"top\"\u003e\n \u003cp\u003egroup 2(n=22)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.52252252252252%\" valign=\"top\"\u003e\n \u003cp\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.71171171171171%\" valign=\"top\"\u003e\n \u003cp\u003eTornetta and Matta grading\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eExcellent\u003c/p\u003e\n \u003cp\u003eGood\u003c/p\u003e\n \u003cp\u003eFair\u003c/p\u003e\n \u003cp\u003ePoor\u003c/p\u003e\n \u003cp\u003eStatisfactory rate\u003c/p\u003e\n \u003cp\u003eFollow up time(month)\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eMajeed score\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.36036036036036%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003cp\u003e12/15(80%)\u003c/p\u003e\n \u003cp\u003e14.6\u0026plusmn;7.7\u003c/p\u003e\n \u003cp\u003e90.7\u0026plusmn;4.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.405405405405407%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003cp\u003e17/22（77.3%）\u003c/p\u003e\n \u003cp\u003e15.7\u0026plusmn;6.9\u003c/p\u003e\n \u003cp\u003e89.0\u0026plusmn;5.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.52252252252252%\" valign=\"top\"\u003e\n \u003cp\u003e0.872\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.554\u003c/p\u003e\n \u003cp\u003e0.974\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003csup\u003ea\u003c/sup\u003ePearson uncorrected \u0026chi;2 test \u0026nbsp; \u003csup\u003e\u0026nbsp;b\u0026nbsp;\u003c/sup\u003et test\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4. \u0026nbsp;\u003c/strong\u003eComplications\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.4029304029304%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.87912087912088%\" valign=\"top\"\u003e\n \u003cp\u003egroup 1(n=15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.824175824175825%\" valign=\"top\"\u003e\n \u003cp\u003egroup 2(n=22)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.893772893772894%\" valign=\"top\"\u003e\n \u003cp\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.4029304029304%\" valign=\"top\"\u003e\n \u003cp\u003eHeterotopic ossification\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eLFCN irritation\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eInfection\u003csup\u003ea\u003c/sup\u003e \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.87912087912088%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.824175824175825%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.893772893772894%\" valign=\"top\"\u003e\n \u003cp\u003e0.341\u003c/p\u003e\n \u003cp\u003e0.011\u003c/p\u003e\n \u003cp\u003e0.027\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003csup\u003ea\u003c/sup\u003ePearson uncorrected \u0026chi;2 test\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Barrel handle-shaped, INFIX, Pelvic fracture","lastPublishedDoi":"10.21203/rs.3.rs-4590388/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4590388/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThis study aimed to compare the biomechanical stability and clinical outcomes of a bent \u0026ldquo;barrel handle\u0026rdquo; connecting rod with a conventional \u0026ldquo;arc\u0026rdquo; rod when using the anterior subcutaneous internal fixator (INFIX) for unstable pelvic fractures.\u003c/p\u003e\u003ch2\u003eMethod\u003c/h2\u003e \u003cp\u003eType C1 pelvic ring injury model specimens were created by performing sacral foramen and pubic ramus osteotomies in 16 cadaveric pelvises. The models were randomly divided into group A (INFIX S1 screw fixation using a \u0026ldquo;barrel handle\u0026rdquo; connecting rod) and group B (INFIX S1 screw fixation using an \u0026ldquo;arc\u0026rdquo; connecting rod). Each model underwent vertical loading of 200\u0026ndash;800 N, and the horizontal and vertical displacement distances of the fractured ends of the pubic ramus were recorded at 200, 400, 600, and 800 N. The treatment outcomes of 37 patients with unstable pelvic fractures were retrospectively evaluated. Among these, 15 patients were treated with the INFIX using the \u0026ldquo;barrel handle\u0026rdquo; connecting rods, while 22 were treated with the INFIX using the \u0026ldquo;arc\u0026rdquo; connecting rod. Outcome measures were postoperative complications (ectopic ossification, anterior exothelial nerve injury, infection), fracture reduction quality (Matta score), and postoperative function (Majeed score).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe experiments showed no significant differences between groups A and B in the horizontal and vertical displacements after vertical compression. Among the 39 clinical cases, two patients were lost to follow-up. The demographic characteristics (sex and age), fracture classification, Injury Severity Score, and body mass index of the two groups were not comparable (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05). There were no significant differences between the two groups in fracture reduction quality, postoperative function, and postoperative complications, except for ectopic ossification. The incidences of anterior exothelial nerve injury and wound infection were significantly lower in the group treated with the INFIX using the \u0026ldquo;barrel handle\u0026rdquo; connecting rod than in the group treated with the INFIX using the \u0026ldquo;arc\u0026rdquo; connecting rod.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThe INFIX using a \u0026ldquo;barrel handle\u0026rdquo; connecting rod achieves similar biomechanical stability and favorable clinical outcomes compared with the INFIX using an \u0026ldquo;arc\u0026rdquo; connecting rod. Furthermore, use of the INFIX with \u0026ldquo;barrel handle\u0026rdquo; connecting rods significantly reduces the incidences of postoperative wound infection and anterior exocortical nerve injury.\u003c/p\u003e","manuscriptTitle":"Biomechanics and clinical outcomes of “barrel handle” connecting rods used in INFIX internal fixation for unstable pelvic fractures: a cadaveric biomechanical study and retrospective cohort study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-16 22:03:52","doi":"10.21203/rs.3.rs-4590388/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f46e8888-bebe-41a7-9bae-2e93c3d119ab","owner":[],"postedDate":"July 16th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-11T08:54:33+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-16 22:03:52","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4590388","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4590388","identity":"rs-4590388","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}