The infraacetabular screw versus the antegrade posterior column screw in acetabulum fractures with posterior column involvement: a biomechanical comparison.

INTRODUCTION: Traditionally, plate osteosynthesis of the anterior column combined with an antegrade posterior column screw is used for fixation of anterior column plus posterior hemitransverse (ACPHT) acetabulum fractures. Replacing the posterior column screw with an infraacetabular screw could improve the straightforwardness of acetabulum surgery, as it can be inserted using less invasive approaches, such as the AIP/Stoppa approach, which is a well-established standard approach. However, the biomechanical stability of a plate osteosynthesis combined with an infraacetabular screw instead of an antegrade posterior column screw is unknown. MATERIAL AND METHODS: Two osteosynthesis constructs were compared in a synthetic hemipelvis model with an ACPHT fracture: Suprapectineal plate + antegrade posterior column screw (APCS group) vs. suprapectineal plate + infraacetabular screw (IAS group). A single-leg stance test protocol with an additional passive muscle force and a cyclic loading of 32,000 cycles with a maximum effective load of 2400 N was applied. Interfragmentary motion and rotation of the three main fracture lines were measured. RESULTS: At the posterior hemitransverse fracture line, interfragmentary motion perpendicular to the fracture line (p < 0.001) and shear motion (p < 0.001) and at the high anterior column fracture line, interfragmentary motion longitudinal to the fracture line (p = 0.017) were significantly higher in the IAS group than in the APCS group. On the other hand, interfragmentary motion perpendicular (p = 0.004), longitudinal (p < 0.001) and horizontal to the fracture line (p = 0.004) and shear motion (p < 0.001) were significantly increased at the low anterior column fracture line in the APCS group compared to the IAS group. CONCLUSIONS: Replacing the antegrade posterior column screw with an infraacetabular screw is not recommendable as it results in an increased interfragmentary motion, especially at the posterior hemitransverse component of an ACPHT fracture.

Operative versus conservative treatment in pelvic ring fractures with sacral involvement.

BACKGROUND: To evaluate the performance in activities of daily living (ADL), level of pain, mortality and rate of complications in patients with a pelvic ring fracture with sacral involvement who were treated conservatively compared to a surgically treated patient collective using percutaneous iliosacral screw fixation. HYPOTHESIS: Conservative treatment does not result in inferior clinical outcome compared to operative treatment. PATIENTS AND METHODS: A retrospective study of 112 conservatively (n=46) or operatively (n=66) treated patients with an isolated posterior or a combined posterior and anterior pelvic ring fracture was performed. The analysis included: age, sex, mechanism of injury, fracture type according to AO/OTA classification, energy of trauma sustained (no-, low-, high-energy trauma), type of treatment (operative or conservative), complications as well as duration of in-hospital stay. To assess clinical and activity outcome, the visual analog scale for pain (VAS), Barthel Scale, American Society of Anaesthesiologists (ASA) scores as well as mortality were assessed. The mean follow-up was 29.3±14.6 months. Furthermore, a geriatric subgroup (n=68, age≥60, low-energy trauma only) was analyzed. RESULTS: The majority of the patients were female (79%) and suffered from low-energy trauma (n=64, 58%). There were no significant differences in the operative and the conservative groups and subgroups concerning VAS, Barthel scores and ASA scores. The survival analyses showed a significantly lower survival rate in the conservative group (41.8±3.6 months) compared to the operative group (55.9±2 months, p=0.002). Similar findings were encountered in the geriatric subgroup analysis. CONCLUSION: This study demonstrates equivalent clinical outcome in conservatively and surgically treated patients using a percutaneous iliosacral screw fixation at a mid-term follow-up. However, operatively treated patients showed decreased mortality. This needs to be carefully considered in clinical decision-making but must be further explored using a prospective randomized study approach. LEVEL OF EVIDENCE: III.

Conservative versus operative treatment of FFP II fractures in a geriatric cohort: a prospective randomized pilot trial.

A clear recommendation regarding treatment strategy of fragility fractures of the pelvic ring is missing. The most typical fracture pattern is a lateral compression type injury with non-displaced fractures of the anterior pubic rami and a unilateral os sacrum fracture (FFP II). We hypothesized that operative treatment would be superior to conservative treatment. From October 2017 to April 2020, a randomized prospective non-blinded trial with n = 39 patients was carried out. Two arms with 17 operative versus 22 conservative cases were created. Inclusion criteria were a posterior pelvic ring fracture FFP type II, age over 60 years and acute fracture (< 3 weeks). Barthel index, pain level (VAS), quality of life (EQ-5D-3L), and Tinetti-Gait Test were determined on admission, at discharge, and after 3, 6, 12 and 24 months. Median follow-up was 12.9 months. The Barthel index (= 0.325), VAS (p = 0.711), quality of life (p = 0.824), and Tinetti-Gait Test (p = 0.913) showed no significant differences between the two groups after 12 months. Two patients switched from the conservative to the operative arm due to persistent immobilization and pain. The one-year mortality rate showed no significant difference (p = 0.175). Our hypothesis that surgical treatment is superior was refuted. No significant benefit was shown in terms of quality of life, mortality and pain levels. The results suggest a more differentiated treatment approach in the future, with initial conservative treatment preferred. A larger multi-center trial is required to confirm these findings.Trial registration: The study was retrospectively registered with the German Clinical Trials Registry (DRKS00013703) on 10/12/2018.

Epidemiology and socioeconomic consequences of work-related pelvic and acetabular fractures recorded in the German Social Accident Insurance.

INTRODUCTION: Pelvic and acetabular fractures can result from work-related accidents and frequently require lengthy medical treatments. Consequently, high medical costs as well as delayed or absent return to work can be the consequence. Therefore, we aimed to study the socioeconomic consequences of work-related pelvic and acetabular fractures. MATERIALS AND METHODS: This retrospective study investigated work-related pelvic and acetabular fractures recorded in the German Social Accident Insurance in 2011 and 2017, in terms of age, sex, type of accident, duration of incapacity to work, reductions in earning capacity, costs for outpatient and inpatient treatment and costs for pension and severance pay. RESULTS: Among a total of 606 injuries in 2011 and 619 injuries in 2017, male patients and patients between 40 and 65 years were predominantly affected. Acetabular fractures caused higher rates of long absence from work of 6-12 months (2011: 24.7% vs. 9.5-16.9%; 2017: 26.1% vs. 6.1-11.0%) and >12 months (2011: 15.8% vs. 9.8-10.2%; 2017: 13.3% vs. 1.9-8.2%) as well as more cases with a reduction in earning capacity of at least 20% (2011: 61 vs. ≤27 cases; 2017: 39 vs. ≤12 cases) compared to pelvic ring fractures. The total costs for pelvic ring and acetabular fractures in the German social accident insurances amounted € 18,726,630 and € 9637,189 in the periods 2011-2020 and 2017-2020, respectively. The average costs per case for treatment and rehabilitation until 2020 was € 19,079 for injuries from 2011 and € 13,629 for injuries from 2017. Acetabular fractures were found to be the most cost-intensive injuries compared to anterior, posterior or complex pelvic ring fractures. CONCLUSIONS: Work-related pelvic and especially acetabular fractures have a considerable socioeconomic impact in the German Social Accident Insurance. Measures to prevent work-related accidents and to improve treatment of pelvic injuries can help to reduce their socioeconomic burden.

The influence of 3D printing on inter- and intrarater reliability on the classification of tibial plateau fractures.

PURPOSE: Tibial plateau fractures continue to be a challenging task in clinical practice and current outcomes seem to provide the potential for further improvement. Especially presurgical understanding of the orientation of fracture lines and fracture severity is an essential key to sufficient surgical treatment. The object of this study was to evaluate the reliability of modern axial CT-based classification systems for tibial plateau fractures. In addition, the diagnostic-added value of 3D printing on the classification systems was investigated. METHODS: 22 raters were asked to classify 22 tibial plateau fractures (11 AO B- and 11 AO C-fractures) with the AO, the 10-Segment and the Revisited Schatzker classification in a three-step evaluation: first only using CT scans, second with 3D volumetric reconstructions and last with 3D-printed fracture models. Inter- and intraobserver agreement and the subjective certainty were analyzed. Statistics were done using kappa values, percentage match and a univariant one-way analysis of variance. RESULTS: The AO classifications interobserver percentage match and kappa values improved for all raters and recorded an overall value of 0.34, respectively, 43% for the 3D print. The 10-Segment classification interobserver agreement also improved with the 3D-printed models and scored an overall kappa value of 0.18 and a percentage match of 79%. Equally the Revisited Schatzker classification increased its values to 0.31 and 35%. The intraobserver agreement showed a moderate agreement for the AO (0.44) and Revisited Schatzker classification (0.42) whereas the 10-Segment classification showed a fair agreement (0.27). Additionally, the raters changed their classification in 36% of the cases after evaluating the fracture with the 3D-printed models and the subjective certainty regarding the decisions improved as categories of self-reliant diagnostic choices were selected 18% (p < 0.05) more often after using the 3D-printed models. CONCLUSION: Based on the measured outcomes it was concluded that the new classification systems show an overall slight to fair reliability and the use of 3D printing proved to be beneficial for the preoperative diagnostics of tibial plateau fractures. The 10-Segment classification system showed the highest percentage match evaluation of all classification systems demonstrating its high clinical value across all levels of user experience.

Does the COVID-19 personal protective equipment impair the surgeon's performance?

INTRODUCTION: Despite increasing vaccination rates, new viral variants of SARS-CoV-2 (severe acute respiratory syndrome coronavirus type 2) are advancing the COVID 19 (coronavirus disease 2019) pandemic and continue to challenge the entire world. Surgical care of SARS-CoV-2 positive patients requires special protective measures. We hypothesized that "COVID-19" personal protective equipment (PPE) during surgery of SARS-CoV-2 positive or potentially positive patients would negatively affect the surgeon and thus the surgical outcome. MATERIALS AND METHODS: Ten experienced trauma surgeons participated in the study. Each surgeon performed two simulated surgeries of a distal tibial fracture on a Sawbone® under standardized conditions either wearing regular PPE or special COVID-19 PPE. Baseline values at rest were acquired for heart rate, blood pressure, saturation of peripheral oxygen (SpO2), respiratory rate and capillary blood gas (CBG) analysis including capillary partial pressure of oxygen (pO2) and carbon dioxide (pCO2), followed by four different standardized tests of attentional performance (TAP). Subsequently, the surgeon performed the first surgery according to a randomly determined order, with regular or COVID-19 PPE conditions in an operation theatre. After each surgery vital signs were acquired and CBG and TAP were performed again. RESULTS: In our simulated surgical procedure heart rate, respiratory rate, systolic and diastolic blood pressure did not show relevant differences. Percutaneously measured SpO2 decreased with additional layers of PPE, while CBG parameters were not affected. TAP tests showed a significant impairment of attention if PPEs were compared to the baseline, but both PPEs had similar results and no meaningful differences could be measured. CONCLUSIONS: According to our results, for surgical procedures additional PPE required during COVID-19 pandemic does not relevant affect the surgeon's mental and physical performance. Surgeries under COVID-19 PPE conditions appear safe and do not increase patient risk. LEVEL OF EVIDENCE: Level I.

Full endoscopic anterior intrapelvic plate osteosynthesis: a cadaveric feasibility study.

In this investigation, it was assumed that it must be possible to visualize the intrapelvic aspect as accustomed by pelvic surgeons using the anterior intrapelvic (modified Stoppa) approach. Moreover, it was hypothesized, that plate mountings will not only be possible for the symphysis but also at the supra- and infrapectineal aspect as well as to the posterior column. Ten anonymized cadaveric specimens were included in this study. A standard laparoscopic totally extraperitoneal (TEP) approach was used. A total of 10 landmarks were defined that are usually within reach in the open anterior intrapelvic (AIP) approach. Moreover, five different plate mountings were tested. The locations were chosen in accordance with the indication spectrum suitable for open surgery through the traditional AIP approach. It was possible to gain intrapelvic visibility in seven of ten cases. In all of those seven cases, it was technically possible to place plates to the symphysis, superior pubic ramus, as well as longer anterior column plates up to the aspect posterior of the acetabulum. In the last four of the seven cases, it was possible to mount plates to the infrapectineal aspect as well as the posterior column, too. The team, previously trained in arthroscopic surgical techniques as well as pelvic trauma surgery, observed a steep learning curve. This investigation demonstrated, that endoscopic anterior intrapelvic plate osteosynthesis was feasible in the majority of the cases in a series of ten cadaveric models. New instruments will be needed such as extra-long rasp elevators, ball-spikes as well as devices to hold and position plates and extra-long self-holding screwdrivers. With these, endoscopic pelvic surgery will likely be a realistic option for selected pelvic trauma cases in the future.

Anterolateral versus modified posterolateral approach for tibial plateau fractures with involvement of the posterior column: a cadaveric study.

INTRODUCTION: The aim of this study was to compare the reduction quality of the anterolateral (AL) and modified posterolateral approach (PL) in lateral tibial plateau fractures involving the posterior column and central segments. METHODS: Matched pairs of pre-fractured cadaveric tibial plateau fractures were treated by either AL approach (supine position) or PL approach (prone position). Reduction was controlled by fluoroscopy and evaluated as satisfying or unacceptable. Afterwards, the reduction was examined by 3D scan. RESULTS: 10 specimens (3 pairs 41B3.1, 2 pairs 41C3.3) were evaluated. PL approach achieved significantly (p 0.00472) better fracture reduction results (0.4 ± 0.7 mm) of the posterior column compared to the AL group (2.1 ± 1.4 mm). Fracture steps involving the central area of the lateral plateau were insufficiently reduced after fluoroscopy using both approaches. CONCLUSION: Optimal reduction of displaced tibial plateau fractures involving the posterolateral column necessitates a posterior approach, which can be conducted in prone or lateral positioning. The anterolateral approach is indicated in fractures with minor displacement of the posterolateral rim but fracture extension in the latero-central segments. In these cases, an additional video-assisted reduction or extended approaches are helpful.

Neurogenic gluteus medius and minimus muscle atrophy with Trendelenburg's sign after a displaced acetabular fracture of the posterior column - A case report.

Traumatic or iatrogenic sciatic nerve injury, but not superior gluteal nerve injury, is a well described complication after acetabular fractures. Most often, sciatic nerve injuries occur in fractures involving the posterior column/wall with a hip dislocation and posterior fracture displacement resulting in narrowing of the greater sciatic foramen and injuring the sciatic nerve passing through. In this case report, a case of abductor mechanism deficiency with positive Trendelenburg's sign after an acetabular fracture of the posterior column with hip dislocation is presented. Postoperative clinical and MRI examination revealed a neurogenic atrophy of gluteus medius and minimus muscles suggesting a superior gluteal nerve injury due to initial subtotal incarceration of the greater sciatic foramen by a displaced posterior fracture fragment. An additional mild sciatic nerve injury resolved in the early postoperative course, while intensive physiotherapy improved the patient's complaints and muscular atrophy caused by the superior gluteal nerve injury within 12 months. This case report intends to raise awareness for rare neurological complications after acetabular fractures for their early detection.

Biomechanical in vitro analysis of a novel flexible implant for pubic symphysis disruption using an ultra-high molecular weight polyethylene fiber cord.

BACKGROUND: Plate osteosynthesis depicts the gold standard to surgically treat pubic symphysis disruptions. However, high rates of implant failure after plate osteosynthesis are reported, probably because of the iatrogenic arthrodesis of this fibrocartilaginous joint. Therefore, flexible implants for treatment of pubic symphysis disruptions appear to be a sensible solution. METHODS: In this biomechanical screening study, we designed and investigated a flexible implant, which consists of two plates connected with an ultra-high molecular weight polyethylene fiber cord. We mechanically tested eye splices as a possible fixation method of the cords by performing tensile load to failure tests. Afterwards, we developed a biomechanically appropriate plate design and cord routing between the plates. Finally, we biomechanically tested the flexible implant under tensile and shear loading until failure. FINDINGS: When fixing a 1 mm ultra-high molecular weight polyethylene fiber cord with eye splices, a load at failure of 1570.74 N was detected under tensile loading. None of the eye splices failed but the cords itself ruptured. The load at failure of the designed cord routing in criss-cross technique and fixation within the plates amounts 4742.09 N under tensile and 2699.77 N under shear load. INTERPRETATION: We developed a novel flexible implant for repair of pubic symphysis disruptions using ultra-high molecular weight polyethylene fiber cords connected to osteosynthesis plates. We identified eye splices as a mechanically optimal fixation method and proved that the ultra-high molecular weight polyethylene fiber cord routing and fixation of the flexible implant clearly withstands physiological forces acting on the pubic symphysis.

Biomechanical analysis of fixation methods in acetabular fractures: a systematic review of test setups.

PURPOSE: Optimal anatomical reduction and stable fixation of acetabular fractures are important in avoiding secondary dislocation and osteoarthritis. Biomechanical studies of treatment options of acetabular fractures aim to evaluate the biomechanical properties of different fixation methods. As the setup of the biomechanical test can influence the experimental results, this review aimed to analyze the characteristics, comparability and clinical implications of studies on biomechanical test setups and finite element analyses in the fixation of acetabular fractures. METHODS: A systematic literature research was conducted according to the PRISMA guidelines, using the PubMed/MEDLINE and Web of Science databases. 44 studies conducting biomechanical analyses of fixation of acetabular fractures were identified, which met the predefined inclusion and exclusion criteria and which were published in English between 2000 and April 16, 2021. The studies were analyzed with respect to distinct parameters, including fracture type, material of pelvis model, investigated fixation construct, loading direction, loading protocol, maximum loading force, outcome parameter and measurement method. RESULTS: In summary, there was no standardized test setup within the studies on fixation constructs for acetabular fractures. It is therefore difficult to compare the studies directly, as they employ a variety of different test parameters. Furthermore, the clinical implications of the biomechanical studies should be scrutinized, since several test parameters were not based on observations of the human physiology. CONCLUSION: The limited comparability and restricted clinical implications should be kept in mind when interpreting the results of biomechanical studies and when designing test setups to evaluate fixation methods for acetabular fractures.

A comparison between Asians and Caucasians in the dimensions of the femoral isthmus based on a 3D-CT analysis of 1189 adult femurs.

INTRODUCTION: For successful intramedullary implant placement at the femur, such as nailing in unstable proximal femur fractures, the use of an implant that at least reaches or exceeds the femoral isthmus and yields sufficient thickness is recommended. A number of complications after intramedullary femoral nailing have been reported, particularly in Asians. To understand the anatomical features of the proximal femur and their ethnic differences, we aimed to accurately calculate the femoral isthmus dimensions and proximal distance of Asians and Caucasians. METHODS: In total, 1189 Asian and Caucasian segmented 3D CT data sets of femurs were analyzed. The individual femoral isthmus diameter was precisely computed to investigate whether gender, femur length, age, ethnicity or body mass index have an influence on isthmus diameters. RESULTS: The mean isthmus diameter of all femurs was 10.71 ± 2.2 mm. A significantly larger diameter was found in Asians when compared to Caucasians (p < 0.001). Age was a strong predictor of the isthmus diameter variability in females (p < 0.001, adjusted r2 = 0.299). With every year of life, the isthmus showed a widening of 0.08 mm in women. A Matched Pair Analysis of 150 female femurs showed a significant difference between isthmus diameter in Asian and Caucasian femurs (p = 0.05). In 50% of the cases the isthmus was found in a range of 2.4 cm between 16.9 and 19.3 cm distal to the tip of the greater trochanter. The female Asian femur differs from Caucasians as it is wider at the isthmus. CONCLUSIONS: In absolute values, the proximal isthmus distance did not show much variation but is more proximal in Asians. The detailed data presented may be helpful in the development of future implant designs. The length and thickness of future standard implants may be considered based on the findings.

The influence of bone quality on radiological outcome in 50 consecutive acetabular fractures treated with a pre-contoured anatomic suprapectineal plate.

PURPOSE: To investigate the range of indications of an anatomical-preshaped three-dimensional suprapectineal plate and to assess the impact of the bone mass density on radiologic outcomes in different types of acetabular fractures. PATIENTS AND METHODS: A consecutive case series of 50 acetabular fractures (patient age 69 ± 23 years) treated with suprapectineal anatomic plates were analyzed in a retrospective study. The analysis included: Mechanism of injury, fracture pattern, surgical approach, need for additional total hip arthroplasty, intra- or postoperative complications, as well as bone mass density and radiological outcome on postoperative computed tomography. RESULTS: Most frequently, anterior column fracture patterns with and without hemitransverse components as well as associated two column fractures were encountered. The anterior intrapelvic approach (AIP) was used in 98% (49/50) of the cases as primary approach with additional utilization of the first window of the ilioinguinal approach in 13/50 cases (26%). Determination of bone density revealed impaired bone quality in 70% (31/44). Postoperative steps and gaps were significantly greater in this subgroup (p < 0.05). Fracture reduction quality for postoperative steps revealed anatomic results in 92% if the bone quality was normal and in 46% if impaired (p < 0.05). In seven cases (14%), the plate was utilized in combination with acute primary arthroplasty. CONCLUSION: A preshaped suprapectineal plate provides good radiological outcomes in a variety of indications in a predominantly geriatric cohort. Impaired bone quality has a significantly higher risk of poor reduction results. In cases with extensive joint destruction, the combination with total hip arthroplasty was a valuable option.

Extended approach to the lateral tibial plateau with central meniscal subluxation in fracture repair: feasibility and first clinical and radiographic results.

PURPOSE: Anatomic reduction in tibial plateau fractures remains to be demanding. For further visualisation of and approach to the joint surface an extended lateral approach using a lateral femoral epicondyle osteotomy and subluxation of the lateral meniscus was recently described. First clinical and radiographic mid-term results of this technique are presented in this feasibility study. METHOD: Ten complex tibial plateau fractures treated with extended lateral approach and lateral meniscal subluxation were prospectively analysed. Clinical and radiographic results were objectified according to the Rasmussen scores. RESULTS: After a median follow-up of 8.6 (IQR 4.3) months good to excellent clinical and radiographic results were noted. The clinical Rasmussen Score showed a median of 25 (IQR 2.8) and radiographic a median of 17 (IQR 2.0) points. CONCLUSION: Good to excellent clinical and radiological scores were obtained after using an extended lateral approach with lateral femoral epicondyle osteotomy and central meniscus subluxation. No approach specific complications could be observed.

[Diagnostic imaging and classification of proximal femoral and tibia fractures in adults]. / Diagnostik und Klassifikation proximaler Femur- und Tibiafrakturen beim Erwachsenen.

BACKGROUND: A confident diagnosis and classification of proximal femoral and tibia fractures are crucial to determine further therapeutic procedures. MATERIALS AND METHODS: In this article the current standards regarding diagnostic imaging of proximal femoral and tibia fractures are presented and the different classification systems are discussed. CONCLUSIONS: Plain radiography in two planes remains the initial investigation of choice for suspected osseous injury. While this is usually sufficient to determine further procedures for injuries of the proximal femur, cross-sectional imaging is normally necessary in the diagnosis of proximal tibia fractures.

The three-dimensional bone mass distribution of the posterior pelvic ring and its key role in transsacral screw placement.

To optimize the placement of iliosacral screws in osteoporotic bone it is essential to know where to find the best purchase. The aim of this study was to determine and visualize the distribution of bone mass in the posterior pelvic ring by using a color-coded thermal map, to differentiate the bone distribution patterns in normal pelvises and in pelvises with impaired bone density and to identify zones in S1 and S2 with particularly good bone quality, in both healthy and osteoporotic pelvises. A total of 324 pelvises were included. The bone density of the posterior pelvic ring, the fifth lumbar vertebral body (L5) and screw corridors S1 and S2 were visualized. Each individual pelvis was measured with a 3D automated program. Two groups were selected - patients with mean bone density in L5 of ≤100 HU (group 1, n = 52) and those with mean bone density >100 HU (group 2, n = 272). Color-coded thermal maps are presented of the bone density distribution in the pelvises. Bone density in L5 correlated significantly with S1 and S2; bone density was significantly higher in the S1 than in the S2 corridor (p < 0.001). Bone was denser in the posterior and upper parts of the S1 body. Bone density was significantly lower in group 2 than in group 1 (p < 0.001). The color-coded "thermal" maps of bone mass distribution can help surgeons to decide where sacroiliac screws are likely to find optimal purchase.

The intra- and interobserver reliability of the Tile AO, the Young and Burgess, and FFP classifications in pelvic trauma.

INTRODUCTION: Several different systems of classification have been developed to understand the complexity of pelvic ring fractures, to facilitate communication between physicians and to support the selection of appropriate therapeutic measures. The purpose of this study was to measure the inter- and intraobserver reliability of Tile AO, Young and Burgess, and FFP classification in pelvic ring fractures. The Rommens classification system (FFP) is analyzed for the first time. MATERIALS AND METHODS: Four reviewers (2 × senior pelvic trauma surgeon, 1 × resident, 1 × medical student) separately analyzed and classified 154 CT scans of patients with pelvic fracture. The Tile AO, the Young and Burgess, and the FFP classifications (subgroup with patients ≥ 60 years) were compared. Another blinded re-evaluation was carried out after 2 months to determine intraobserver reliability. RESULTS: The overall interobserver agreement was fair for all classification systems (ICC: OTA 0.55, Young and Burgess 0.42, FFP 0.54). For specific categories, (e.g. type B or C fractures), there was a substantial agreement between the experienced surgeons (kappa: OTA 0.64, Young and Burgess 0.62, FFP 0.68). For inexperienced observers, there was a fair agreement in all systems (kappa: OTA 0.23, Young and Burgess 0.23, FFP 0.36). CONCLUSIONS: All three classifications reach their maximum reliability with advanced expertise in the surgery of pelvic fractures. The novel FFP classification has proved to be at least equivalent when directly compared to the established systems. The FFP classification system showed substantial reliability in patients older than 60 years.

Femoral antecurvation-A 3D CT Analysis of 1232 adult femurs.

INTRODUCTION: For optimal treatment of femoral fractures, it is essential to understand the anatomical antecurvation of the human femur. Recent clinical studies have highlighted the problem of distal anterior encroachment or even perforation of the nail tip. The aim of this study was to accurately describe the femoral antecurvation in a large cohort. Another objective was to identify the most important influences on femoral antecurvation, such as age, femur length, gender and ethnicity. METHODS: A three dimensional modelling and analytical technology was applied for the analysis of 1,232 femurs. Individual femoral antecurvation was precisely computed to determine whether gender, femur length, age, ethnicity or body mass index influence the radius of curvature (ROC). RESULTS: The calculated mean ROC for all femurs was 943 mm. The lowest ROC of 826 mm was found in female Asian femurs. A regression analysis demonstrated that age and femur length could predict the variability of the curvature, with femoral length as most powerful predictor. A matched pair subgroup analysis between Asians and Caucasians could not show any significant differences of ROC values. CONCLUSIONS: The mean radius of the femoral antecurvation may be smaller than previously reported revealing a significant mismatch between the actual individual anatomy and existing implants. In opposite to existing literature, this study suggests, that antecurvation differences between various ethnicities may exclusively be attributed to differences in femoral length and age. The findings of this study may be found helpful in the development of novel designs for intra- and extramedullary implants.

Determination of bone density in patients with sacral fractures via CT scan.

BACKGROUND: Gold standard to diagnose osteoporosis is standard dual-energy X-ray absorptiometry (DXA). CT is a standard diagnostic tool to detect injuries to the pelvic ring. The aim of the study was to collect information on bone density without DXA by determination of Hounsfield units (HU) in CT scans of patients with sacral fractures, to draw conclusions on the prevalence of osteoporosis in patients admitted to the investigating institution. HYPOTHESIS: Is the determination of HU in CT scans a useful method to gain more information about bone density in patients with sacral fractures? PATIENTS AND METHODS: We performed a retrospective analysis of all patients treated from 2004-2014 with sacral fractures confirmed with a CT scan. A total of 531 patients (398 female, 133 male) were included in the study. Bone density was measured with CT scans in Hounsfield units in vertebral body L5. The assessment was performed by placing a single oval over the trabecular bone in the axial view. In the sagittal plane, the correct position in the middle of the vertebral body was checked. As in previously published studies, we defined bone of less than 100 HU as osteoporotic, 100-150 HU as osteopenic and above 150 HU as normal. RESULTS: In 71.6% of the patients, bone density was reduced. Seventy-five percent of patients aged 65 or more exhibited manifest osteoporosis. With each additional year of age, bone density decreased by 2.7 Hounsfield units (p˂0.001). Female patients were predominant in the patient group with osteoporotic bone (p˂0.001). CONCLUSIONS: There is significant prevalence of reduced bone density in the investigated patient group. The methodology used in this study is an uncomplicated procedure to further assess bone quality in patients with fractures of the pelvic ring. Fractures of the posterior pelvic ring in women over 65 years with low-energy trauma are most probably osteoporotic. LEVEL OF EVIDENCE: III.

Growth of Cutibacterium acnes is common on osteosynthesis material of the shoulder in patients without signs of infection.

Background and purpose - Cutibacterium acnes, formerly known as Propionibacterium acnes, is often isolated from deep tissues of the shoulder. It is recognized as an important causative agent of foreign-material associated infections. However, the incidence and significance of its detection in tissues from patients without clinical evidence for infection is unclear. We assessed the incidence of C. acnes colonization of osteosynthesis material in asymptomatic patients, and evaluated the short-term outcome in relation to the microbiological findings. Patients and methods - We microbiologically analyzed osteosynthesis material of 34 asymptomatic patients after surgery on the clavicle. Material obtained from 19 asymptomatic patients after osteosynthesis of the fibula served as a control group. Patients were clinically followed up for 3-24 months after removal of the osteosynthesis material. Results - Bacteria were recovered from devices in 29 of 34 patients from the clavicle group. 27 of 29 positive samples grew C. acnes. Isolation of C. acnes was more common in male than in female patients. No bacterial growth was observed on foreign material from patients in the fibula group. All patients remained asymptomatic at follow-up. Interpretation - Growth of C. acnes is common on osteosynthesis material of the shoulder, especially in males. Samples were positive irrespective of clinical signs of infection. Therefore, detection of C. acnes in this clinical setting is of questionable clinical significance. The high positivity rate in asymptomatic patients discourages routine sampling of material in cases without clinical evidence for infection.