Direct contact and very rapid valgus distortion characterise the injury mechanism of anterior cruciate ligament ruptures in judo.

PURPOSE: To analyse anterior cruciate ligament (ACL) rupture (ACLR) injury mechanisms in competitive judo using systematic video analysis, focusing on contact situations and biomechanics. METHODS: Seventeen videos of judo competitions wherein athletes developed ACLRs were included and retrospectively evaluated by five analysts. In all videos, the moment of initial contact and the index frame were defined. The judo techniques leading to the injury; the occurrence of direct contact, indirect contact or noncontact mechanisms; the time interval between the initial contact and index frame; the positions of the hip, knee and foot in relation to the initial contact and index frame; and the balance status during the initial contact and index frame were recorded. RESULTS: Eleven (65%) of ACLRs in judo involved direct contact. The mean time interval between initial contact and index frame was 15 ± 22 ms. Thirteen (77%) athletes were not balanced at initial contact. In the index frame, the hip was abducted in all cases and in combination with internal rotation in 12 (71%) cases. From initial contact to index frame, hip flexion increased in all cases; at index frame, the knee joint was internally rotated relative to the trunk in 12 (71%) cases, and the knee flexion angles increased from the initial contact. In the index frame, the foot was externally rotated relative to the knee in 12 (71%) cases, and severe valgus development of the knee with valgus collapse was observed in 14 (82%) cases. CONCLUSIONS: A direct attack on the knee was the most common injury mechanism observed. Valgus distortion appears to be the most important component of the mechanism of injury. With this knowledge, 'modified defence reactions' for specific judo techniques can be developed to reduce the injury risk. LEVEL OF EVIDENCE: Level IV.

Changing trends in maxillofacial injuries among paediatric, adult and elderly populations: A 22-year statistical analysis of 3424 patients in a tertiary care centre in Northwest Italy.

BACKGROUND: This retrospective study analysed the epidemiology of maxillofacial trauma over 22 years to assess whether there have been significant changes in the causes and characteristics of fractures in paediatric, adult and elderly populations. MATERIALS AND METHODS: The following data were collected: age, sex, injury cause and mechanism, fracture site, Facial Injury Severity Scale, associated injuries, time of injury, type of treatment and length of hospital stay. The patients were analysed by age group (children [≤16 years], adults [17-60 years] and elderly [>60 years]) and divided into two time groups (group 1: 2001-2011; group 2: 2012-2022) that were compared to each other. Statistical analyses were performed using SPSS software. RESULTS: Between 01 January 2001 and 31 December 2022, 3535 patients (2690 males and 845 females, mean age 39.3 years) were admitted for facial fractures. The comparison of the two temporal periods showed a decrease in the prevalence of males (p = .02), in road traffic injuries (p < .001), and in fractures of the lower third of the face (p = .005); there were significant increases in the mean age (p < .001), prevalence of the elderly (p = .006) and in fall- and assault-related injuries (p < .001 and p = .03, respectively). Assault injuries increased only in the 17-60 age group (p = .02) while RTA-related fractures decreased in all age groups (p < .05 for all comparisons). Bicycle accidents increased significantly, with a parallel decrease in motor vehicle accidents (both p < .001). Fall-related fractures increased only in 17-60 and >60 age groups (p < .001 and p = .02, respectively). CONCLUSIONS: This study shows significant changing trends in the epidemiology of maxillofacial trauma. While road traffic policies have been effective in the last years, preventive measures for falls in the elderly population and new legislative measures to prevent interpersonal violence should be advocated.

Parametric analysis of craniocerebral injury mechanism in pedestrian traffic accidents based on finite element methods.

PURPOSE: The toughest challenge in pedestrian traffic accident identification lies in ascertaining injury manners. This study aimed to systematically simulate and parameterize 3 types of craniocerebral injury including impact injury, fall injury, and run-over injury, to compare the injury response outcomes of different injury manners. METHODS: Based on the total human model for safety (THUMS) and its enhanced human model THUMS-hollow structures, a total of 84 simulations with 3 injury manners, different loading directions, and loading velocities were conducted. Von Mises stress, intracranial pressure, maximum principal strain, cumulative strain damage measure, shear stress, and cranial strain were employed to analyze the injury response of all areas of the brain. To examine the association between injury conditions and injury consequences, correlation analysis, principal component analysis, linear regression, and stepwise linear regression were utilized. RESULTS: There is a significant correlation observed between each criterion of skull and brain injury (p < 0.01 in all Pearson correlation analysis results). A 2-phase increase of cranio-cerebral stress and strain as impact speed increases. In high-speed impact (> 40 km/h), the Von Mises stress on the skull was with a high possibility exceed the threshold for skull fracture (100 MPa). When falling and making temporal and occipital contact with the ground, the opposite side of the impacted area experiences higher frequency stress concentration than contact at other conditions. Run-over injuries tend to have a more comprehensive craniocerebral injury, with greater overall deformation due to more adequate kinetic energy conduction. The mean value of maximum principal strain of brain and Von Mises stress of cranium at run-over condition are 1.39 and 403.8 MPa, while they were 1.31, 94.11 MPa and 0.64, 120.5 MPa for the impact and fall conditions, respectively. The impact velocity also plays a significant role in craniocerebral injury in impact and fall loading conditions (the p of all F-test < 0.05). A regression equation of the craniocerebral injury manners in pedestrian accidents was established. CONCLUSION: The study distinguished the craniocerebral injuries caused in different manners, elucidated the biomechanical mechanisms of craniocerebral injury, and provided a biomechanical foundation for the identification of craniocerebral injury in legal contexts.

Fascicle Behavior and Muscle Activity of The Biceps Femoris Long Head during Running at Increasing Speeds.

Hamstring strain injuries (HSIs) are prevalent in sports involving high-speed running and most of the HSIs are biceps femoris long head (BFlh) injuries. The primary cause for HSIs during high-speed running remains controversial due to the lack of in vivo measurement of the BFlh muscle behavior during running. Therefore, the purpose of this study was to quantify the muscle-tendon unit (MTU) and fascicle behavior of BFlh during running. Seven college male sprinters (22.14 ± 1.8 years; 177.7 ± 2.5 cm; 70.57 ± 5.1 kg; personal bests in 100m: 11.1 ± 0.2 s) were tested on a motorized treadmill instrumented with two force plate for running at 4, 5, 6m/s. The ground reaction force (GRF), 3D lower limb kinematics, EMG, and ultrasound images of biceps femoris long head (BFlh) in the middle region were recorded simultaneously. BFlh fascicles undergo little length change (about 1 cm) in the late swing phase during running at three submaximal speeds. BFlh fascicle lengthening accounted for about 30% of MTU length change during the late swing phase. BFlh was most active during the late swing and early stance phases, ranging from 83%MVC at a running speed of 4 m/s to 116%MVC at 6 m/s. Muscle fascicles in the middle region of BFlh undergo relatively little lengthening relative to the MTU in the late swing phase during running in comparison to results from simulation studies. These results suggest that there is a decoupling between the fascicle in the middle region and MTU length changes during the late swing phase of running.

Characteristics and comparative study of thoracolumbar spine injury and dislocation fracture due to tertiary trauma.

PURPOSE: Thoracolumbar spine injury is frequently seen with high-energy trauma but dislocation fractures are relatively rare in spinal trauma, which is often neurologically severe and requires urgent treatment. Therefore, it is essential to understand other concomitant injuries when treating dislocation fractures. The purpose of this study is to determine the differences in clinical features between thoracolumbar spine injury without dislocation and thoracolumbar dislocation fracture. METHODS: We conducted an observational study using the Japan Trauma Data Bank (2004-2019). A total of 734 dislocation fractures (Type C) and 32,382 thoracolumbar spine injuries without dislocation (Non-type C) were included in the study. The patient background, injury mechanism, and major complications in both groups were compared. In addition, multivariate analysis of predictors of the diagnosis of dislocation fracture using logistic regression analysis were performed. RESULTS: Items significantly more frequent in Type C than in Non-type C were males, hypotension, bradycardia, percentage of complete paralysis, falling objects, pincer pressure, accidents during sports, and thoracic artery injury (P < 0.001); items significantly more frequent in Non-type C than in Type C were falls and traffic accidents, head injury, and pelvic trauma (P < 0.001). Logistic regression analysis showed that younger age, male, complete paralysis, bradycardia, and hypotension were associated with dislocation fracture. CONCLUSION: Five associated factors were identified in the development of thoracolumbar dislocation fractures. LEVEL OF EVIDENCE: III.

Injury-mechanism directness as a key factor for fracture laterality in pediatric extremity fractures.

BACKGROUND: Associations between certain extremity fracture sites and laterality in pediatric trauma are well known, whereas the rationale for such laterality tendencies are unclear. We hypothesized that the laterality tendency of a specific fracture would be affected by directness of injury mechanism and not by the fracture site itself. METHODS: We retrospectively enrolled 1382 children (aged 2-16 years) who were diagnosed with extremity fractures sustained during loss-of-balance situations and investigated the laterality tendencies (dominant vs. non-dominant extremity) of specific fracture sites. Multivariate analyses were sequentially performed to adjust for potential confounding variables-with and without injury-mechanism directness as a covariate. RESULTS: In the upper extremities, the non-dominant side was more prone to fractures (p < 0.001), especially of the distal supracondylar humerus, radial and/or ulnar shaft, and distal radius. In the lower extremities, the dominant side was more frequently fractured (p < 0.001), especially at the tibial shaft and distal tibia. However, the predisposing effects of specific fracture sites on fracture laterality were not statistically significant when in analysis adjusted for injury-mechanism directness as a covariate. Fracture laterality was affected by whether the injury mechanism was direct or indirect. Indirect injury to the upper extremity was strongly associated with non-dominant arm injury (odds ratio 0.686 [95% CI 0.517-0.991]; p = 0.009), whereas indirect injury to the lower extremity was strongly associated with dominant leg injury (odds ratio 2.138 [95% CI 1.444-3.165]; p < 0.001). CONCLUSIONS: Injury-mechanism directness, rather than fracture site itself, is a key factor that affects fracture laterality in pediatric extremity fractures. These findings are helpful for improving our understanding of which factors may affect fracture laterality among children.

Does mechanism of injury impact the outcome of operative fixation of geriatric proximal humerus fractures.

BACKGROUND: The purpose of this study is to determine the effects of energy mechanism on outcomes following repair of proximal humerus fractures (PHF) in the middle aged and geriatric population. METHODS: Two hundred sixty-nine patients who presented to our academic medical center between 2006 and 2020, and underwent operative treatment of a proximal humerus fracture were prospectively enrolled in an IRB-approved database. Patients above 55 were divided into high energy (motor vehicle accident, pedestrian struck, or fall > 2 stairs) or low energy mechanisms (fall from standing or < 2 stairs). Of 97 patients with complete documentation and follow-up, 72 were included in the low velocity (LV) group and 25 were included in the high velocity (HV) group. Demographic information, primary injury details, healing and time to union, range of motion (ROM), complications, and need for reoperation were assessed at initial presentation and subsequent follow-up appointments. RESULTS: Mean age, BMI, and gender were significantly different between the LV and HV cohorts (p = 0.01, 0.04, 0.01). OTA/AO fracture patterns were similar between the groups. (p = 0.14). Bony healing and complications occurred with similar frequency between groups (p = 1.00, 0.062). The most common complications in the LV and HV groups included avascular necrosis (9.7%, 16.0%), and screw penetration (4.2%, 12.0%), while the HV group also had rotator cuff issues including weakness and tendonitis (12.0%). There was no significant difference in need for reoperation between cohorts (p = 0.45). Time to healing, shoulder ROM, and DASH scores did not differ between each group. CONCLUSIONS: Energy and mechanism demonstrates similar outcomes in operatively treated proximal humerus fractures. These factors should not play a role in decisions for surgery in these patients and can help guide patient expectations.

Distal biceps tendon ruptures occur with the almost extended elbow and supinated forearm - an online video analytic study.

BACKGROUND: Distal biceps tendon ruptures can lead to significant restrictions in affected patients. The mechanisms of injury described in scientific literature are based exclusively on case reports and theoretical models. This study aimed to determine the position of the upper extremities and forces involved in tendon rupture through analyzing video recordings. METHODS: The public YouTube.com database was queried for videos capturing a clear view of a distal biceps tendon rupture. Two orthopedic surgeons independently assessed the videos for the activity that led to the rupture, the arm position at the time of injury and the forces imposed on the elbow joint. RESULTS: Fifty-six video segments of a distal biceps rupture were included (55 male). In 96.4%, the distal biceps tendon ruptured with the forearm supinated and the elbow isometrically extended (non-dynamic muscle engagement) (71.4%) or slightly flexed (24%). The most common shoulder positions were adduction (85.7%) and neutral position with respect to rotation (92.9%). Most frequently a tensile force was enacted on the elbow (92.9%) and the most common activity observed was deadlifting (71.4%). CONCLUSION: Distal biceps tendon ruptures were most commonly observed in weightlifting with a slightly flexed or isometrically extended elbow and forearm supination. These observations may provide useful information for sports specific evidence-based injury prevention, particularly in high performing athletes and individuals engaged in resistance training. LEVEL OF EVIDENCE: Observational study.

Injury and illness epidemiology in professional Asian football: lower general incidence and burden but higher ACL and hamstring injury burden compared with Europe.

BACKGROUND: While football injury and illness epidemiology surveillance at professional club level in Europe is available, epidemiological data from other continents are lacking. PURPOSE: Investigating injury and illness epidemiology in professional Asian football. STUDY DESIGN: Descriptive prospective study. METHODS: Professional teams from the Asian Football Confederation (AFC) league were followed prospectively for three consecutive AFC seasons (2017 through 2019, 13 teams per season, 322 team months). Time-loss injuries and illnesses in addition to individual match and training exposure were recorded using standardised digital tools in accordance with international consensus procedures. RESULTS: In total, 232 665 hours of exposure (88.6% training and 11.4% matches) and 1159 injuries were recorded; 496 (42.8%) occurred during matches, 610 (52.6%) during training; 32 (2.8%) were reported as 'not applicable' and for 21 injuries (1.8%) information was missing. Injury incidence was significantly greater during match play (19.2±8.6 injuries per 1000 hours) than training (2.8±1.4, p<0.0001), resulting in a low overall incidence of 5.1±2.2.The injury burden for match injuries was greater than from training injuries (456±336 days per 1000 hours vs 54±34 days, p<0.0001). The two specific injuries causing the greatest burden were complete ACL ruptures (0.14 injuries (95% CI 0.9 to 0.19) and 29.8 days lost (29.1 to 30.5) per 1000 hours) and hamstring strains (0.86 injuries (0.74 to 0.99) and 17.5 days (17.0 to 18.1) lost per 1000 hours).Reinjuries constituted 9.9% of all injuries. Index injuries caused 22.6±40.8 days of absence compared with 25.1±39 for reinjuries (p=0.62). The 175 illnesses recorded resulted in 1.4±2.9 days of time loss per team per month. CONCLUSION: Professional Asian football is characterised by an overall injury incidence similar to that reported from Europe, but with a high rate of ACL ruptures and hamstring injury, warranting further investigations.

The three-dimensional reconstruction of an Achilles tendon rupture in a professional football player reveals a multiplanar injury mechanism.

Achilles tendon rupture (ATR) is a rare although very serious injury for football players; currently, studies on ATR in football are scant. This case report intends to firstly describe the situational pattern and three-dimensional mechanism of the ATR injury occurred to a professional football player during the last UEFA 2020 Championship. To reconstruct the full 3D joint kinematics throughout the injury action, the model-based image-matching technique was used. The key findings were: (i) ATR injury combined a sudden ankle dorsiflexion action with an internal plantarflexion moment while performing a crossover cut at high speed; (ii) a multi-planar loading occurred during the push-off phase.Level of evidence V.

Different injury patterns exist among patients undergoing operative treatment of isolated PCL, combined PCL/ACL, and isolated ACL injuries: a study from the Swedish National Knee Ligament Registry.

PURPOSE: To compare demographic characteristics and concomitant injury patterns in patients undergoing primary isolated posterior cruciate ligament reconstruction (PCL-R) and combined posterior cruciate ligament (PCL) and anterior cruciate ligament (ACL) reconstruction (PCL-R/ACL-R) with isolated ACL reconstruction (ACL-R) as a reference using data from the Swedish National Knee Ligament Registry (SNKLR). METHODS: This cohort study based on the SNKLR comprised patients undergoing either PCL-R, ACL-R, or combined PCL-R/ACL-R between January 1, 2005 and December 31, 2019 in Sweden. Demographic and surgery-related data with regards to injury mechanism, concomitant intraarticular lesions and their treatment, neurovascular damage, and concomitant ligamentous injuries were extracted. Exclusion criteria included concomitant fractures of the femur, fibula, patella or tibia, and quadriceps or patellar tendon injury. RESULTS: A total of 45,564 patients were included in this study. Isolated PCL-R, combined PCL-R/ACL-R, and isolated ACL-R were performed in 192 (0.4%), 203 (0.5%) and 45,169 (99.1%) patients, respectively. Sports were identified as the cause of 64% of PCL-Rs, 54% of PCL-R/ACL-Rs, and 89% of ACL-Rs, while a traffic-related mechanism was identified in 20% of PCL-Rs, 27% of PCL-R/ACL-Rs and 2% of ACL-Rs. Meniscus injury prevalence was 45% in ACL-Rs, 31% in PCL-R/ACL-Rs and 16% in isolated PCL-Rs (p < 0.001). Cartilage injuries were more common in PCL-R (37%) and PCL-R/ACL-R patients (40%) compared to ACL-R patients (26%, p < 0.001). Concomitant knee ligament injury was identified in 28-44% of PCL-R/ACL-R patients. Neurovascular injuries were present in 9% of PCL-R/ACL-Rs, 1% of PCL-Rs, and 0.3% of ACL-Rs (p < 0.001). CONCLUSION: Differences in injury mechanisms among patient groups confirm that operatively treated PCL tears are frequently caused by both traffic and sports. Cartilage and ligament injuries were more frequent in patients with PCL-R compared to ACL-R. Consequently, combined PCL and ACL tears should raise suspicion for concomitant knee lesions with clinical relevance during the operative treatment of these complex injuries. LEVEL OF EVIDENCE: III.

Does the Lauge-Hansen Injury Mechanism Predict Posterior Malleolar Fracture Morphology?

The Lauge-Hansen ankle fracture classification system is widely accepted and is utilized to describe and predict ankle fracture patterns based on the mechanism of injury. Multiple studies have shown inconsistencies in the Lauge-Hansen's ability to predict fracture patterns based on the mechanism of injury. We set out to determine if the posterior malleolar fracture pattern is associated with the fracture types described by Lauge-Hansen. In this retrospective cohort study, we reviewed 153 patients with trimalleolar ankle fractures as diagnosed using computed tomography scans. Timing of injury was from February 2013 to August 2017. Patient ages ranged between 18 and 89 years old. Each patient had a complete clinical and radiographic workup including a preoperative computed tomographic scan following initial fracture reduction in the emergency room. We classified each ankle fracture based on plain film radiographs using the Lauge-Hansen classification scheme. Each individual posterior malleolar fracture was evaluated on computed tomography imaging and described using both the Haraguchi and Bartonicek-Rammelt classification systems. Of the 153 patients identified with trimalleolar ankle fractures, 70% were female (±20%), the mean age was 51 y (±8 y), and the mean body mass index was 30 kg/m2 (±3 kg/m2). We did not observe a significant association between the Lauge-Hansen injury mechanism and either the Bartonicek-Rammelt or the Haraguchi trimalleolar ankle fracture classification systems (chi-square correlation tests p > .05).

Young adults in motor vehicle collisions in Norway: user safety errors observed in majority of cases with severe or fatal injuries.

PURPOSE: We performed a multidisciplinary investigation of young adults involved in motor vehicle collisions (MVCs) to elucidate injury mechanisms and the role of passive safety equipment such as seat belts and airbags. METHODS: MVCs resulting in death or serious injuries to the driver or passengers aged 16-24 years in southeastern Norway during 2013-2016 were investigated upon informed consent. We assessed the crash scene, the motor vehicle (MV) interior and exterior, and analyzed data from medical records, forensic autopsies and reports from police and civil road authorities. RESULTS: This study included 229 young adult occupants involved in 212 MVCs. The Maximum Abbreviated Injury Scale (MAIS) score was ≥2 in 111 occupants, of which 22 were fatalities. In 59% (65/111) of the cases with MAIS score ≥2 injuries, safety errors and occupant protection inadequacies were considered to have contributed to the injury outcome. Common errors were seatbelt non-use and misuse, carrying insecure luggage, and the seat back being too reclined. MAIS score ≥2 head/neck injuries were observed in side impacts despite correct seatbelt use, related to older MVs lacking side airbag curtains. The independent risk factors for MAIS score ≥2 injuries included not using a seatbelt, driving under the influence of alcohol or drugs, nighttime driving, side impacts, heavy collision partner, and MV deformation. CONCLUSION: User safety errors (not using a seatbelt, seatbelt misuse, excessive seat-back reclining, and insecure cargo) and a lack of occupant protection in older MVs resulted in young adults sustaining severe or fatal injuries in MVCs.

Profiling of the immune repertoire in COVID-19 patients with mild, severe, convalescent, or retesting-positive status.

Forty-seven samples of peripheral blood mononuclear cells from four groups of coronavirus disease (COVID)-19 patients (mild, severe, convalescent, retesting-positive) and healthy controls were applied to profile the immune repertoire of COVID-19 patients in acute infection or convalescence by transcriptome sequencing and immune-receptor repertoire (IRR) sequencing. Transcriptome analyses showed that genes within principal component group 1 (PC1) were associated with infection and disease severity whereas genes within PC2 were associated with recovery from COVID-19. A "dual-injury mechanism" of COVID-19 severity was related to an increased number of proinflammatory pathways and activated hypercoagulable pathways. A machine-learning model based on the genes associated with inflammatory and hypercoagulable pathways had the potential to be employed to monitor COVID-19 severity. Signature analyses of B-cell receptors (BCRs) and T-cell receptors (TCRs) revealed the dominant selection of longer V-J pairs (e.g., IGHV3-9-IGHJ6 and IGHV3-23-IGHJ6) and continuous tyrosine motifs in BCRs and lower diversity of TCRs. These findings provide potential predictors for COVID-19 outcomes, and new potential targets for COVID-19 treatment.

Knee position at the moment of bone bruise could reflect the late phase of non-contact anterior cruciate ligament injury rather than the mechanisms leading to ligament failure.

PURPOSE: The aim of the present study was to trace knee position at the time of bone bruise (BB) and investigate how much this position departed from the knee biomechanics of an in vivo flexion-extension. METHODS: From an original cohort of 62 patients, seven (11%) presented bicompartmental edemas and were included in the study. 3D models of bones and BB were obtained from MRI. Matching bone edemas, a reconstruction of the knee at the moment of BB was obtained. For the same patients, knee kinematics of a squat was calculated using dynamic Roentgen sterephotogrammetric analysis (RSA). Data describing knee position at the moment of BB were compared to kinematics of the same knee extrapolated from RSA system. RESULTS: Knee positions at the moment of BB was significantly different from the kinematics of the squat. In particular, all the patients' positions were out of squat range for both anterior and proximal tibial translation, varus-valgus rotation (five in valgus and two in varus), tibial internal-external rotation (all but one, five externally and one internally). A direct comparison at same flexion angle between knee at the moment of BB (average 46.1° ± 3.8°) and knee during squat confirmed that tibia in the former was significantly more anterior (p < 0.0001), more externally rotated (6.1 ± 3.7°, p = 0.04), and valgus (4.1 ± 2.4°, p = 0.03). CONCLUSION: Knee position at the moment of Bone bruise position was out of physiological in-vivo knee range of motion and could reflect a locked anterior subluxation occurring in the late phase of ACL injury rather than the mechanism leading to ligament failure. LEVEL OF EVIDENCE: Level IV.

Primary radial nerve palsy associated with humeral shaft fractures according to injury mechanism: is early exploration needed?

BACKGROUND: Radial nerve palsy is a common complication associated with humeral shaft fractures. The purposes of this study were (1) to evaluate the status of primary radial nerve palsy in patients with humeral shaft fracture according to injury mechanism, (2) to estimate the risk factors of primary RNP, and (3) to evaluate whether early exploration is helpful for radial nerve recovery. METHODS: This study analyzed 162 patients with humeral shaft fractures from January 2014 to December 2019. All patients were surgically treated in our hospital. Of these, 109 high-energy injuries were identified and compared with 53 low-energy injuries. The risk factors of radial nerve palsy were analyzed, and the prevalence of radial nerve palsy and status of radial nerve exploration according to injury mechanism were evaluated. Nerve recovery rate according to early nerve exploration was investigated. RESULTS: There were 31 cases of radial nerve palsy among 162 patients: 27 in the high-energy humeral shaft fracture group and 4 in the low-energy humeral shaft fracture group. Logistic regression analysis for risk factors showed that the injury mechanism was significantly associated with primary radial nerve palsy. Among 31 radial nerve palsy patients, 21 radial nerves were explored and 19 radial nerves recovered completely (80.6%). In the high-energy humeral shaft fracture group, 18 radial nerves were explored during surgery among 27 radial nerve palsy cases, and 16 cases recovered (88.9%). The other 9 radial nerves were not explored, and only 5 cases recovered (55.6%). CONCLUSIONS: This study confirmed that the incidence of radial nerve paralysis was higher in high-energy humeral shaft fractures than in low-energy fractures. The more common fracture patterns were oblique, transverse, wedge, and comminuted in high-energy humeral shaft fracture. This study suggests that these patterns are not directly associated with radial nerve palsy, but that high-energy injury is associated with a specific fracture pattern. Early nerve exploration during surgical treatment in patients with radial nerve palsy associated with humeral shaft fracture was helpful especially after high-energy injury.

Injury characteristics and management of orthopaedic trauma in refugee children.

PURPOSE: Several factors affect injury types in childhood. The aim of the study was to evaluate the musculoskeletal injury types, treatment modalities, and demographic characteristics of refugee children and to reveal the differences from native children. METHODS: A total of 1297 patients (897 females, 400 males) treated in our clinic between January 2014 and January 2019 were included in the study. The mean age of the patients was 8.9 ± 5.1 in refugees and 7.5 ± 4.6 in the native group (range, 0-18 years). The patients were evaluated in terms of age, gender, mechanism of injury, location and type of fracture, presence of accompanying injuries, surgical technique, complications, and treatment modalities. RESULTS: The trauma mechanism differed significantly between the groups, high-energy traumas such as falling from a height, fight/assault injury, gunshot injury, and work injury were found more frequently in the refugee group (p = 0.001). The rates of CRIF, ORIF, graft/flap surgery, and hospitalization time were observed to be significantly higher in the refugee group (p = 0.013). No significant difference was observed between groups in terms of demographic distribution, injury location, and complications. CONCLUSION: This population-based, cross-sectional study emphasizes that the refugee children have different injury mechanisms. Improved living conditions may reduce musculoskeletal injury in this population.

Inducing pilon fractures in human cadaveric specimens depending on the injury mechanism: a fracture simulation.

BACKGROUND: Operative management of pilon fractures, especially high-energy compression injuries, is a challenge. Operative education is of vital importance to handle these entities. Not rarely, it is cut by economics and staff shortage. As public awareness toward operative competence rises, surgical cadaver courses that provide pre-fractured specimens can improve realism of teaching scenarios. The aim of this study is to introduce a realistic pilon fracture simulation setup regarding the injury mechanism. MATERIALS AND METHODS: 8 cadaveric specimens (two left, six right) were fixed onto a custom drop-test bench in dorsiflexion (20°) and light supination (10°). The proximal part of the lower leg was potted, and the specimen was exposed to a high energetic impulse via an axial impactor. CT imaging was performed after fracture simulation to detect the exact fracture patterns and to classify the achieved fractures by two independent trauma surgeons. (AO/OTA recommendations and the Rüedi/Allgöwer). RESULTS: All cadaveric specimens could be successfully fractured: 6 (75%) were identified as a 43-C fracture and 2 (25%) as 43-B fracture type. Regardless of the identical mechanism two different kinds of fracture types were reported. In five cases (62.5%), the fibula was also fractured and in three specimens, a talus fracture was described. There was no statistically significant correlation found regarding Hounsfield Units (HU) and age as well as HU and required kinetic energy. CONCLUSION: A high energetic axial impulse on a fixed ankle specimen in light dorsiflexion (20°) and supination (10°) induced by a custom-made drop-test bench can successfully simulate realistic pilon fractures in cadaveric specimens with intact soft tissue envelope. Although six out of eight fractures (75%) were classified as a 43-C fracture and despite putting a lot of effort into the mechanical setup, we could not achieve an absolute level of precision. Therefore, we suggest that the injury mechanism is most likely a combination of axial loading, shear and rotation. LEVEL OF EVIDENCE: III.

Mechanisms of mid-thoracic spine fracture/dislocation due to falls during horse racing: A report of two cases.

We reported two cases of jockeys who sustained fracture/dislocation of the mid-thoracic spine due to traumatic falls during horse racing. We examined the injury mechanism based upon the patients' diagnostic images and video footage of races, in which the accidents occurred. Admission imaging of patient 1 (a 42 years old male) revealed T5 burst fracture with bony retropulsion of 7 mm causing complete paralysis below T5/6. There existed 22° focal kyphosis at T5/6, anterolisthesis of T5 relative to T6, T5/6 disc herniation, cord edema and epidural hemorrhage from T4 through T6, and cord injury from C3 through C6. Admission imaging of patient 2 (a 23 years old male) revealed T4/5 fracture/dislocation causing incomplete paralysis below spinal level. There existed compression fractures at T5, T6, and T7; 4 mm anterior subluxation of T4 on T5; diffuse cord swelling from T3 through T5; comminuted fracture of the C1 right lateral mass; right frontal traumatic subarachnoid hemorrhage; and extensive diffuse axonal injury. The injuries were caused by high energy flexion-compression of the mid-thoracic spine with a flexed posture upon impact. Our results suggest that substantially greater cord compression occurred transiently during trauma as compared to that documented from admission imaging. Video footage of the accidents indicated that the spine buckled and failed due to abrupt pocketing and deceleration of the head, neck and shoulders upon impact with the ground combined with continued forward and downward momentum of the torso and lower extremities. While a similar mechanism is well known to cause fracture/dislocation of the cervical spine, it is less common and less understood for mid-thoracic spine injuries. Our study provides insight into the etiology of fracture/dislocation patterns of the mid-thoracic spine due to falls during horse racing.

Ankle Fracture Epidemiology in the United States: Patient-Related Trends and Mechanisms of Injury.

Current nationwide epidemiological data regarding ankle fractures are scarce. Such information is important towards better quantifying the mortality associated with such injuries, financial impact, as well as the implementation of preventative measures. This study evaluated the epidemiology of ankle fractures that occurred during a 5-year period. Specifically, we evaluated demographics, mechanism of injury, and disposition. The National Electronic Injury Surveillance System was queried to identify all patients with ankle fractures that presented to US hospital emergency departments between 2012 and 2016. Census data were used to determine the incidence rates of ankle fractures in terms of age, sex, and race. There was an estimated total of 673,214 ankle fractures that occurred during this period, with an incidence rate of 4.22/10,000 person-years. The mean age of patients with an ankle fracture was 37 ± 22.86 (SD) years; 23.5% of ankle fractures occurred in patients aged 10 to 19 years (7.56/10,000 person-years). In addition, 44% of ankle fractures occurred in men (3.81/10,000 person-years), whereas 56% occurred in women (4.63/10,000 person-years). Data on race/ethnicity were available for 71% of the subjects, with incidence rates of 2.85/10,000 person-years for whites, 3.01/10,000 person-years for blacks, and 4.08/10,000 person-years for others. The most common mechanism of injury was falls (54.83%), followed by sports (20.76%), exercise (16.84%), jumping (4.42%), trauma (2.84%), and other (0.30%). For disposition, 81.84% of patients were treated and released, 1.43% were transferred, 16.01% were admitted, 0.59% were held for observation, and 0.13% left against medical advice. The highest incidence of ankle fractures in men occurred in the 10-to-19-years age group, but women were more commonly affected in all other age groups.