An unusual presentation of penetrating bladder injury with vesicocutaneous fistula: a case report.

BACKGROUND: Blunt trauma to the urinary bladder is common with penetrating injury being a rare occasion. Most common entry pint for penetrating injuries includes buttock, abdomen and perineum with thigh being rare. There are a number of complications that may develop as a result of penetrating injury with vesicocutanous fistula being a rare occurrence that usually presents with typical sign and symptoms. CASE PRESENTATION: We present a rare case of penetrating bladder injury through medial upper thigh as an entry point that had complicated into vesicocutaneous fistula with atypical presentation of long-standing pus discharge that had been managed by incision and drainage several times with no success. MRI demonstrated a presence of fistula tract and a foreign body (piece of wood) in-situ confirmed the diagnosis. CONCLUSION: Fistulas are a rare complication of bladder injuries and can cause negative impact on the quality of life of patients. Delayed urinary tract fistulations and secondary thigh abscesses are uncommon therefore a high index of suspicion is needed for early diagnosis. This case emphasizes the importance of radiological tests in aiding the diagnosis and ultimately proper management.

Treatment of Hip Dislocation in Cerebral Palsy with Extraarticular Intervention.

PURPOSE OF THE STUDY Hip dislocation is one of the major causes of disability in children with cerebral palsy (CP). Surgical treatment can be achieved using different techniques including proximal femoral varus derotation osteotomy (FVDRO), pelvic osteotomies, and open hip reduction (OHR). However, we claim that pathologies originating from extraarticular structures in the dislocated hip in CP can be reconstructed by extraarticular methods and OHR may not always be necessary. Therefore, this study aims to discuss the results of hip reconstruction with extraarticular intervention in patients with CP. MATERIAL AND METHODS In total, 141 hips (95 patients) were included in the study. All patients underwent FVDRO, either with or without a Dega osteotomy. Changes in the Acetabular Index (AI), Migration Index (MI), neck-shaft angle (NSA), and center-edge angle (CEA) were assessed on the preoperative, postoperative, and final follow-up anterior-posterior radiographs of the pelvis. RESULTS Median age was 8 years (range between 4-18 years). The average follow-up duration was 5 years (range between 2-9 years). Changes in AI, MI, NSA and CEA values were statistically significant for postop and follow-up periods when compared to preoperative values. Of the 141 operated hips, 8 (5.6%) hips required revision surgery due to redislocation/resubluxation detected at the follow-ups, and unilateral operation can be accepted as a risk factor for redislocation. CONCLUSIONS Our results demonstrate that reconstructive treatment consisting of FVDRO, medial capsulotomy (in the case of reduction difficulty) and transiliac osteotomy (in the case of acetabular dysplasia) provides satisfactory outcomes in hip dislocation in CP. Key words: hip displacement, cerebral palsy, hip reduction.

Determining Radiographic Reliability of Pelvic Landmarks in Assessing Limb Length Discrepancy Following Total Hip Arthroplasty.

Limb length discrepancy (LLD) is a frequent complication following total hip arthroplasty (THA) often associated with patient dissatisfaction. Radiographic landmarks are commonly used to determine limb length, but their reliability and accuracy remain to be validated. One-hundred and sixty-two preoperative standing pelvic radiographs from patients undergoing THA were measured using four common landmarks (teardrop, ischial tuberosity, obturator foramen, and iliac crest.) LLD and angular differences between measurements were obtained. Comparison of these landmarks for measuring leg lengths showed weak correlation and wide ranges of LLD for each method - in some cases differing by 30 mm. Angular comparisons showed similar results. Surgeons should be cautioned that there is no standard and reliable method for radiographic measurement of leg length in association with hip replacement surgery and use of these techniques in clinical and research settings should be approached cautiously. (Journal of Surgical Orthopaedic Advances 32(1):028-031, 2023).

Current Concepts in the Resection of Bone Tumors Using a Patient-Specific Three-Dimensional Printed Cutting Guide.

Orthopedic oncology has begun to use three-dimensional-printing technology, which is expected to improve the accuracy of osteotomies, ensure a safe margin, and facilitate precise surgery. However, several difficulties should be considered. Cadaver and clinical studies have reported more accurate osteotomies for bone-tumor resection using patient-specific cutting guides, especially in challenging areas such as the sacrum and pelvis, compared to manual osteotomies. Patient-specific cutting guides can help surgeons achieve resection with negative margins and reduce blood loss and operating time. Furthermore, this patient-specific cutting guide could be combined with more precise reconstruction using patient-specific implants or massive bone allografts. This review provides an overview of the basic technologies used in the production of patient-specific cutting guides and discusses their current status, advantages, and limitations. Moreover, we summarize cadaveric and clinical studies on the use of these guides in orthopedic oncology.

EFFECTIVENESS OF INTRA-SCOPE CHANNEL PLASTIC STENT RELEASE IN ENDOSCOPIC ULTRASOUND-GUIDED PELVIC ABSCESS DRAINAGE.

Abscess endoscopic ultrasound pelvic abscess drainage plastic stent; rectal carcinoma.

Sex Cord-Stromal Tumors of the Ovary.

Ovarian sex cord-stromal tumors (OSCSTs) are a rare group of ovarian neoplasms that can be benign or malignant. They are classified into pure sex cord tumors, pure stromal tumors, and mixed SCST. The most common malignant OSCSTs are adult granulosa cell tumors. In contrast to the more common ovarian epithelial malignancies, OSCSTs present in younger patients, often at early stages, with better prognoses. Imaging features are variable, and pathology is required for diagnosis. However, certain tumors demonstrate characteristic imaging appearances that can be useful in narrowing the differential diagnosis.

Femoral posture during embryonic and early fetal development: An analysis using landmarks on the cartilaginous skeletons of ex vivo human specimens.

The pre-axial border medially moves between the fetal and early postnatal periods, and the foot sole can be placed on the ground. Nonetheless, the precise timeline when this posture is achieved remains poorly understood. The hip joint is the most freely movable joint in the lower limbs and largely determines the lower-limb posture. The present study aimed to establish a timeline of lower-limb development using a precise measurement of femoral posture. Magnetic resonance images of 157 human embryonic samples (Carnegie stages [CS] 19-23) and 18 fetal samples (crown rump length: 37.2-225 mm) from the Kyoto Collection were obtained. Three-dimensional coordinates of eight selected landmarks in the lower limbs and pelvis were used to calculate the femoral posture. Hip flexion was approximately 14° at CS19 and gradually increased to approximately 65° at CS23; the flexion angle ranged from 90° to 120° during the fetal period. Hip joint abduction was approximately 78° at CS19 and gradually decreased to approximately 27° at CS23; the average angle was approximately 13° during the fetal period. Lateral rotation was greater than 90° at CS19 and CS21 and decreased to approximately 65° at CS23; the average angle was approximately 43° during the fetal period. During the embryonic period, three posture parameters (namely, flexion, abduction, and lateral rotation of the hip) were linearly correlated with each other, suggesting that the femoral posture at each stage was three-dimensionally constant and exhibited gradual and smooth change according to growth. During the fetal period, these parameters varied among individuals, with no obvious trend. Our study has merits in that lengths and angles were measured on anatomical landmarks of the skeletal system. Our obtained data may contribute to understanding development from anatomical aspects and provide valuable insights for clinical application.

Effects of Walking Speed and Added Mass on Hip Joint Quasi-Stiffness in Healthy Young and Middle-Aged Adults.

Joint quasi-stiffness has been often used to inform exoskeleton design. Further understanding of hip quasi-stiffness is needed to design hip exoskeletons. Of interest are wearer responses to walking speed changes with added mass of the exoskeleton. This study analyzed hip quasi-stiffness at 3 walking speed levels and 9 added mass distributions among 13 young and 16 middle-aged adults during mid-stance hip extension and late-stance hip flexion. Compared to young adults, middle-aged adults maintained a higher quasi-stiffness with a smaller range. For a faster walking speed, both age groups increased extension and flexion quasi-stiffness. With mass evenly distributed on the pelvis and thighs or biased to the pelvis, both groups maintained or increased extension quasi-stiffness. With mass biased to the thighs, middle-aged adults maintained or decreased extension quasi-stiffness while young adults increased it. Young adults decreased flexion quasi-stiffness with added mass but not in any generalizable pattern with mass amounts or distributions. Conversely, middle-aged adults maintained or decreased flexion quasi-stiffness with even distribution on the pelvis and thighs or biased to the pelvis, while no change occurred if biased to the thighs. In conclusion, these results can guide the design of a hip exoskeleton's size and mass distribution according to the intended user's age.

[Primary Leiomyosarcoma of the Epididymis : A Case Report].

A 63-year-old man presented with right scrotal swelling. A physical examination revealed a painless, palpable mass in the right scrotum. The mass was well defined and lobulated. Subsequently, a diagnosis of right epididymal tumor was made, and right high orchiectomy was performed. Hematoxylin-eosin and immunostaining revealed leiomyosarcoma of the epididymis. When a diagnosis of epididymal malignant tumor is made, the standard treatment is radical orchiectomy.

Preliminary data on the neurophysiological evaluation of male sexual dysfunction in patients with pelvic ring fractures: a multicenter retrospective study.

OBJECTIVE: Traumatic pelvic ring fractures include several comorbidities due to the close anatomical relationship between the skeletal system, pelvic organs, and neurovascular structures. In this retrospective multicenter study, we evaluated patients complaining of sexual dysfunction following pelvic ring fractures, assessed through different neuro-physiological examinations. PATIENTS AND METHODS: Patients were enrolled one year after the injury according to their reported ASEX scores and evaluated on the basis of the Tile's type of pelvic fracture. Lower limb and sacral somatosensory evoked potentials, pelvic floor electromyography, bulbocavernosus reflex and pelvic floor motor evoked potentials were recorded, according to the neurophysiological indications. RESULTS: A total of 14 male patients (mean age 50.4; 8 subjects Tile-type B and 6 Tile-type C) were enrolled. The ages between the Tile B group and the Tile C group of patients were not significantly different (p=0.187), while the ASEX scores were significantly different (p=0.014). In 57% of patients (n=8), no alterations in nerve conduction and/or pelvic floor neuromuscular responses were found. In 6 patients, electromyographic signs of denervation were revealed (2 patients), and alterations of the sacral efferent nerve component were detected in 4 patients. CONCLUSIONS: Sexual dysfunctions after a traumatic pelvic ring fracture are more common in Tile-type B. Our preliminary data did not reveal a significant association with neurogenic aetiology. Other causes could explain the complaining impairments.

Predictors of clinical and surgical characteristics of giant stones of the urinary bladder: a retrospective study.

BACKGROUND: Giant stones of the urinary bladder (GSBs) are rare and usually presented as case reports. We aimed to assess the clinical and surgical characteristics of GSBs and identify their predictors. METHODS: A retrospective study of 74 patients with GSBs who presented between July, 2005 and June, 2020 was performed. Patients' demographics, clinical presentations, and surgical peculiarities were studied. RESULTS: Older age and male gender were risk factors for the occurrence of GSBs. The irritative lower urinary tract symptoms (iLUTS) were the main presenting symptoms (97.3%). Most patients were treated with cystolithotomy (90.1%). Univariate analyses showed that solitary (p < 0.001) and rough surface (P = 0.009) stones were significant factors for occurrence of iLUTS as the presenting symptoms. Also, the severity of symptoms (p = 0.021), rough surface (p = 0.010) and size (p < 0.001) of stones, and farmer occupation (p = 0.009) were significantly associated with adherence of the stone to the bladder mucosa at surgery. In multivariate analysis, the rough surface (p = 0.014) and solitary (p = 0.006) stones, and concomitant ureteral stones (p = 0.020) were independently associated with iLUTS as the main presentation. However, the stone size and severity of iLUTS were the independently associated factors for adherence of GSBs to the bladder mucosa. CONCLUSIONS: Solitary GSB, rough surface and the association with ureteral stones are independent risk factors for the occurrence of long-standing iLUTS. The stone size and severity of iLUTS were the independent predictors of adherence of GSBs to the bladder mucosa. Cystolithotomy is the main treatment, but it may be more difficult when there is bladder mucosa adherence.

Surgical and Anatomical Basics of Pelvic Debulking Surgery for Advanced Ovarian Cancer - the "Hudson Procedure" as a Cornerstone of Complete Cytoreduction.

Ovarian cancer (OC) is the fifth most common cause of death in women and accounts for more deaths than any other cancer of the female reproductive tract. OC usually spreads through peritoneal dissemination and direct invasion. Optimal cytoreduction (no macroscopic residual disease) and adjuvant platinum-based chemotherapy are the fundaments of OC treatment. OC is usually diagnosed at advanced stages, hence the obliteration of the Douglas pouch by the tumor as well as disseminated pelvic peritoneal carcinomatosis are commonly seen. Radical surgical cytoreduction typically requires a retroperitoneal approach to the pelvic masses and multivisceral resections in the upper abdomen. In 1968, Christopher Hudson introduced a new retroperitoneal surgical technique ("radical oophorectomy") for fixed ovarian tumors. Since then, numerous modifications have been described, including visceral peritonectomy, the "cocoon" technique, Bat-shaped en-bloc total peritonectomy (Sarta-Bat approach), or en-bloc resection of the pelvis. Although these modifications expanded the classical description in many ways, the concepts and key surgical steps are derived from the Hudson procedure. However, there are some gaps or disagreements regarding the anatomical or practical rationale for certain surgical steps. The purpose of this article is to outline the critical steps of radical pelvic cytoreduction ("Hudson procedure"), and to delineate the anatomical basis for the procedure in the proposed form. In addition, we discuss the controversies and address the perioperative morbidity associated with the procedure.

Relationship between spinal imbalance and knee osteoarthritis by using full-body EOS.

BACKGROUND: Orthostatic state is maintained by harmonizing the spine, pelvis and lower extremities. In the past few decades, several studies have demonstrated the associations between spinal imbalance and generalized osteoarthritis. The compensatory mechanisms of pelvis translation and knee flexion, however, have not been fully assessed. METHODS: A total of 213 volunteers, over 40 years of age, were recruited. Radiological measurements were performed by EOS imaging system. Pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), sagittal vertical axis (SVA), global tilt (GT), hip-knee-angle (HKA), knee flexion angle (KFA), lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA) were measured. On the basis of SRS-Schwab, the subjects were classified into decompensated group (PI-LL > 20°), compensated group(10° ≤ PI-LL ≤ 20°), and normal group (PI-LL < 10°). Differences in radiographic parameters among groups were evaluated. Data of Knee Society Score (KSS) and Oswestry Disability Index (ODI) score were collected via questionnaires. RESULTS: Decompensated group showed larger pelvic parameters (PT) and low extremity parameters (LDFA, MPTA, HKA and KFA) than normal group (P < 0.05). Pelvic parameter was larger in the compensated group (median = 31°) compared to the normal group (median = 17°) (P < 0.05). There was no difference in low extremity parameters between the compensated and normal groups. At the sagittal plane, the radiological parameters of spine were greater in subjects with patellofemoral joint pain (PFP) than without PFP (P = 0.058). Higher PI-LL values were observed in women (P < 0.05). CONCLUSIONS: A correlation between sagittal spinal imbalance and knee joint angles was recognized. The progression of knee and low back pain was associated with the severity of sagittal spinal imbalance. Pelvic retroversion was considered to be the probable compensatory mechanism.

Gynaecoid Pelvis among Female Patients Attending Department of Radiology of a Tertiary Care Centre: A Descriptive Cross-sectional Study.

Introduction: The bony pelvis consists of the two hip bones, the sacrum and the coccyx. The bony pelvis is divided into the greater pelvis and the lesser pelvis. The junction between the greater and the lesser pelvis is the pelvic inlet. The transverse and anteroposterior dimensions of the pelvic inlet will classify the pelvis as the anthropoid, gynaecoid, android, and platypelloid pelvis. Knowledge of female pelvis type is important for obstetricians to know the process of labour which can decrease the morbidity and mortality of mothers and neonates. Thus, the aim of this study was to find out the prevalence of gynaecoid pelvis among female patients attending the Department of Radiology of a tertiary care centre. Methods: This was a descriptive cross-sectional study conducted in the Department of Radiology of a tertiary care centre from 24 July 2022 to 15 November 2022 after approval from the Institutional review committee (Reference number: 11/022). The study included radiographs of the female pelvis without any bony pathology and developmental anomalies. Anteroposterior and transverse dimensions of the pelvic inlet were measured using a digital ruler in a computer. A convenience sampling method was done. Point estimate and 95% confidence interval were calculated. Results: Among total female patients, the gynaecoid pelvis was found in 28 (46.66%) (34.04-59.28, 95% Confidence Interval). Mean anteroposterior and transverse diameters for the gynaecoid pelvis were observed to be 12.85±1.0 cm and 13.66±1.07 cm respectively. Conclusions: The prevalence of gynaecoid pelvis was similar to the other similar studies conducted in similar settings. Keywords: female; pelvis; radiology.

Fixation of pelvic acetabular fractures using 3D-printed fracture plates: a cadaver study.

Open reduction and internal fixation of pelvic acetabular fractures are challenging due to the limited surgical exposure from surrounding abdominal tissue. There have been a number of recent trials using metallic 3D-printed pelvic fracture plates to simplify and improve various elements of these fracture fixation surgeries; however, the amount of time and accuracy involved in the design and implantation of customised plates have not been well characterised. This study recorded the amount of time related to the design, manufacture and implantation of six customised fracture plates for five cadaveric pelvic specimens with acetabular fracture, while manufacturing, and surgical accuracy was calculated from computed tomography imaging. Five of the fracture plates were designed within 9.5 h, while the plate for a pelvis with a pre-existing fracture plate took considerably longer (20.2 h). Manufacturing comprised 3D-printing the plates in Ti6Al4V with a sintered laser melting (SLM) 3D-printer and post-processing (heat treatment, smoothing, tapping threads). The manufacturing times varied from 27.0 to 32.5 h, with longer times related to machining a thread for locking-head screws with a multi-axis computer numerical control (CNC) mill. For the surface of the plate in contact with the bone, the root-mean-square errors of the print varied from 0.10 to 0.49 mm. The upper range of these errors was likely the result of plate designs that were relatively long with thin cross-sections, a combination that gives rise to high thermal stresses when using a SLM 3D-printer. A number of approaches were explored to control the trajectories of locking or non-locking head screws including guides, printed threads or hand-taps; however, the plate with CNC-machined threads was clearly the most accurate with screw angulation errors of 2.77° (range 1.05-6.34°). The implanted position of the plates was determined visually; however, the limited surgical exposure and lack of intra-operative fluoroscopy in the laboratory led to high inaccuracies (translational errors of 1.74-13.00 mm). Plate mal-positioning would lead to increased risk of surgical injury due to misplaced screws; hence, it is recommended that technologies that can control plate positioning such as fluoroscopy or alignment guides need to be implemented into customised plate design and implantation workflow. Due to the plate misalignment and the severe nature of some acetabular fractures comprising numerous small bone fragments, the acetabular reduction exceeded the clinical limit of 2 mm for three pelvises. Although our results indicate that customised plates are unsuitable for acetabular fractures comprising six or more fragments, confirmation of this finding with a greater number of specimens is recommended. The times, accuracy and suggested improvements in the current study may be used to guide future workflows aimed at producing customised pelvic fracture plates for greater numbers of patients.

Mejora significativa de la estabilidad a carga axial con el fijador externo pélvico pretensado: análisis biomecánico en un modelo con lesión Tile tipo C / Significant improvement in axial load stability with the pre-tensioned pelvic external fixator: A biomechanical analysis in a model with type C Tile lesion

Objetivo: Comprobar si la aplicación de fijación externa mediante barra curva conectada a clavos de Schanz supraacetabulares confiere mayor estabilidad al anillo pélvico con una lesión tipo Tile C1 cuando se realiza el montaje con la barra pretensada que con el montaje estándar (sin pretensar). Material y métodos: Pelvis sintéticas (N=5) con lesión verticalmente inestable estabilizada con ambos montajes, se sometieron a carga axial progresiva. Se midieron las fuerzas aplicadas y las variaciones en las posiciones de marcadores situados en la articulación sacroilíaca y la sínfisis se registraron con un sistema óptico. Se determinaron los desplazamientos relativos entre las superficies lesionadas, la rigidez, la resistencia y el modo de fallo de cada montaje. Resultados: Con el fijador pretensado, la rigidez del montaje en la articulación sacroilíaca resultó muy superior a la del montaje convencional (p=0,043) multiplicándola por 3,45, siendo 2,06 veces mayor en la sínfisis. La resistencia ante el fallo también fue superior, multiplicándola por 2 (p=0,043). Discusión: El aumento de estabilidad a carga axial con el fijador externo pretensado concuerda con su capacidad de producir compresión activa simultánea en los elementos posteriores y anteriores del anillo pélvico, demostrada previamente. Este resultado soporta los excelentes resultados clínicos preliminares obtenidos como tratamiento provisional. Conclusiones: El fijador externo pretensado aumenta la estabilidad axial de los elementos óseos posteriores del anillo pélvico con lesión tipo Tile C1 en modelo sintético, sin disminuir la capacidad de estabilización anterior propia de la fijación externa anterior.(AU)

Objective: The aim of our work is to check if the use of a pre-tensed bar connected to 2supra-acetabular Schanz pins is more stable in a pelvic with a tile C1 injury. Material and methods: We used synthetic pelvis (N=5) with a unstable vertical injury, stabilized with both the standard and the pre-tensed system. They both were submitted to axial loading. We measured applied forces and the position of markers that were positioned in the sacroiliac and symphysis joints. We determined the relative movements between injured surfaces, rigidity, resistance and when each system failed. Results: When using the pre-tensed fixator, the rigidity was much higher in the sacro-iliac joint (P=.043) being 3.45 times higher, being also 2.06 times higher in pubic symphysis (P=.043). The resistance against failure was 2 times higher too (P=.043). Discussion: The increased axial stability with the pre-tensed external fixator accords with its ability to make active compression in both posterior and anterior elements of the pelvic ring, which was previously demonstrated. This result supports the preliminary clinic outcomes that were obtained. Conclusions: The pre-tensed external fixator increases the axial stability of the pelvic ring's posterior elements in a synthethic pelvis with a Tile C1 injury, without decreasing it's capacity to achieve an anterior stability.(AU)

[Translated article] Significant improvement in axial load stability with the pre-tensioned pelvic external fixator: A biomechanical analysis in a model with type C Tile lesion / Mejora significativa de la estabilidad a carga axial con el fijador externo pélvico pretensado: análisis biomecánico en un modelo con lesión Tile tipo C

Objetivo: Comprobar si la aplicación de fijación externa mediante barra curva conectada a clavos de Schanz supraacetabulares confiere mayor estabilidad al anillo pélvico con una lesión tipo Tile C1 cuando se realiza el montaje con la barra pretensada que con el montaje estándar (sin pretensar). Material y métodos: Pelvis sintéticas (N=5) con lesión verticalmente inestable estabilizada con ambos montajes, se sometieron a carga axial progresiva. Se midieron las fuerzas aplicadas y las variaciones en las posiciones de marcadores situados en la articulación sacroilíaca y la sínfisis se registraron con un sistema óptico. Se determinaron los desplazamientos relativos entre las superficies lesionadas, la rigidez, la resistencia y el modo de fallo de cada montaje. Resultados: Con el fijador pretensado, la rigidez del montaje en la articulación sacroilíaca resultó muy superior a la del montaje convencional (p=0,043) multiplicándola por 3,45, siendo 2,06 veces mayor en la sínfisis. La resistencia ante el fallo también fue superior, multiplicándola por 2 (p=0,043). Discusión: El aumento de estabilidad a carga axial con el fijador externo pretensado concuerda con su capacidad de producir compresión activa simultánea en los elementos posteriores y anteriores del anillo pélvico, demostrada previamente. Este resultado soporta los excelentes resultados clínicos preliminares obtenidos como tratamiento provisional. Conclusiones: El fijador externo pretensado aumenta la estabilidad axial de los elementos óseos posteriores del anillo pélvico con lesión tipo Tile C1 en modelo sintético, sin disminuir la capacidad de estabilización anterior propia de la fijación externa anterior.(AU)

Objective: The aim of our work is to check if the use of a pre-tensed bar connected to 2supra-acetabular Schanz pins is more stable in a pelvic with a tile C1 injury. Material and methods: We used synthetic pelvis (N=5) with a unstable vertical injury, stabilized with both the standard and the pre-tensed system. They both were submitted to axial loading. We measured applied forces and the position of markers that were positioned in the sacroiliac and symphysis joints. We determined the relative movements between injured surfaces, rigidity, resistance and when each system failed. Results: When using the pre-tensed fixator, the rigidity was much higher in the sacro-iliac joint (P=.043) being 3.45 times higher, being also 2.06 times higher in pubic symphysis (P=.043). The resistance against failure was 2 times higher too (P=.043). Discussion: The increased axial stability with the pre-tensed external fixator accords with its ability to make active compression in both posterior and anterior elements of the pelvic ring, which was previously demonstrated. This result supports the preliminary clinic outcomes that were obtained. Conclusions: The pre-tensed external fixator increases the axial stability of the pelvic ring's posterior elements in a synthethic pelvis with a Tile C1 injury, without decreasing it's capacity to achieve an anterior stability.(AU)