Low-energy Mechanism Research Articles

In-Hospital Adverse Events in Older Patients With Hip Fracture: A Multicenter Retrospective Study

The main objective of this study was to measure the incidence of in-hospital adverse events in older adults presenting to the emergency department (ED) with an isolated traumatic hip fracture. The secondary objective was to identify the risk factors of adverse outcomes in those patients. Retrospective database analysis. Adults aged ≥65years presenting to 1 of the 3 Quebec level 1 adult trauma centers' ED between 2003 and 2017 with an isolated hip fracture. The main outcome was a composite of any adverse events defined as extended length of stay (LOS) >21days, in-hospital complications (delirium, pressure ulcers, urinary tract infection, pneumonia, deep venous thrombosis, or pulmonary embolism), and mortality. Outcomes were also analyzed separately. Multivariable logistic regression modeling was used to identify factors associated with adverse events. We included 4569 patients (female: 74.8%; mean age: 83.7 years). Low energy mechanisms were the most frequent cause of injury (68.4%), and the median LOS was 13days (interquartile range, 8-21). A total of 1829 patients (40.0%) suffered an in-hospital adverse event: extended LOS (n= 1106; 24.2%), death (n= 365, 8.0%), and ≥1 complications (n= 892, 19.5%). Risk factors of any in-hospital adverse event included aged ≥75years [75-84 years: adjusted odds ratio (AOR), 1.44; 95% CI, 1.17-1.76; ≥85 years: AOR, 2.11; 95% CI, 1.72-2.58], male sex (AOR, 1.35; 95% CI, 1.17-1.56), cardiovascular disease (AOR, 1.47; 95% CI, 1.23-1.77), major cognitive disorder (AOR, 1.51; 95% CI, 1.26-1.80), and ≥2 comorbidities (AOR, 1.40; 95% CI, 1.02-1.93). Direct admission from ED to the operating room was associated with decreased risk of any adverse event (AOR, 0.87; 95% CI, 0.76-0.99). Two out of five patients presenting to a level-1 trauma center with an isolated hip fracture suffered from an adverse event. Aged ≥75years, male sex, cardiovascular diseases, major cognitive disorder, and ≥2 comorbidities were significant risk factors. These factors may guide early identification of high-risk patients in the ED.

Play Turned Painful: A Teenager's Tibial Pilon Fracture from A Simple Jump.

An 18-year-old male presented with severe left ankle pain and inability to bear weight after jumping from a three-foot platform. Physical examination revealed decreased range of motion of the left ankle without visible deformity or neurovascular deficits. Imaging studies showed a vertical fracture of the distal tibia-a pilon fracture without fibular involvement. Pilon fractures involve the distal tibial articular surface and are rare. They typically result from high-energy trauma and often involve the fibula. This case illustrates a low-energy mechanism resulting in a pilon fracture without fibular involvement in a young patient without typical risk factors. It highlights the importance of considering pilon fractures in low-energy ankle injuries and the need for appropriate management even in less-complex cases.

Trends in screening and treatment of osteoporosis after periprosthetic fractures from 2010 to 2020.

Periprosthetic fractures (PPF) typically occur from low-energy mechanisms and are pathognomonic for osteoporosis. However, osteoporosis is often underrecognized and undertreated. The aim of this study was to examine trends in dual energy X-ray absorptiometry (DXA) scans and treatment of osteoporosis after PPF between 2010 and 2020. Patients older than 40 who experienced a lower extremity PPF between 2010 and 2020 and had no prior history of osteoporosis screening or treatment were identified utilizing a large national administrative database. Rates of bone mineral density (BMD) measurement using DXA and anti-osteoporotic treatment with pharmacotherapy, or either intervention within 1year following experiencing a PPF were determined. The rate of change for these interventions was calculated using the compounded annual growth rate (CAGR), with linear regression used to determine whether trends were statistically significant. In total, 5.7% and 3.6% of patients were screened and treated for osteoporosis, respectively. Between 2010 and 2020, there was no significant change in rates of osteoporosis screening (CAGR + 0.1%; p = 0.13), treatment (CAGR - 2.4%; p = 0.29), or either intervention (CAGR - 1.1%; p = 0.77) within 1year following PPF. Factors associated with intervention included older age, female sex, and increased comorbidities. Our study found that there has been no significant change in the rates of osteoporosis screening or treatment within 1year following PPF. Orthopedic surgeons and allied healthcare workers can play an integral role in helping to curtail the osteoporosis epidemic.

Pediatric Tibial Shaft Fractures: A Comprehensive Review

Tibial shaft fractures are among the most common pediatric long bone fractures. These fractures have significant implications for growth, function and alignment, often requiring precise management to prevent complications such as limb length discrepancies and angular deformities. This review focuses on the classification, etiology and management of pediatric tibial shaft fractures, emphasizing recent advancements and remaining challenges. A comprehensive literature review was conducted in November 2024 using PubMed, Medline and Scopus. Articles were selected based on relevance to etiology, classification and management strategies. Both recent and foundational studies were included to provide a comprehensive perspective. The review explores the major types of tibial shaft fractures in children, including Toddler’s fractures (and spiral fractures), transverse fractures, greenstick fractures, stress fractures, segmental fractures and comminuted fractures, focusing on their etiology, age-specific prevalence, clinical presentation, imaging findings, management strategies and potential complications. Younger children typically experience fractures due to low-energy mechanisms, such as twisting injuries, resulting in spiral or greenstick fractures. Older children and adolescents are more prone to high-energy trauma, causing transverse, comminuted or segmental fractures, often associated with fibular involvement. Most fractures are treated non-operatively using casting techniques tailored to fracture stability, angulation and age. Surgical interventions, including flexible intramedullary nailing, external fixation and plating, are reserved for complex or unstable fractures, open injuries or cases involving neurovascular compromise. Advances in classification systems, imaging modalities and surgical techniques have improved outcomes, yet opportunities exist to develop growth-preserving methods and improve long-term functional recovery. Future research should prioritize optimizing individualized management strategies and exploring innovative technologies to enhance diagnostic accuracy and treatment efficacy.

Proximal Tibia Fractures.

Proximal tibia fractures in children pose challenges in management due to the complex anatomy in this region. The relationship between the proximal tibial physis, proximal tibial apophysis, extensor mechanism, and nearby vascular structures allows for potential injuries from toddler-aged children through adolescence. The most common injuries include tibial tubercle fractures, proximal tibia physeal fractures, and proximal tibia metaphyseal fractures; they may result from both low-energy and high-energy mechanisms. Nonoperative treatment is indicated for nondisplaced or adequately reduced fractures, while operative treatment is indicated for irreducible fractures or fractures with loss of adequate reduction. Complications of these injuries may include growth arrest, limb length discrepancy, angular deformity, vascular compromise, and compartment syndrome.

Discovery of New Synthetic Routes of Amino Acids in Prebiotic Chemistry.

The origin of life on Earth remains one of the most perplexing challenges in biochemistry. While numerous bottom-up experiments under prebiotic conditions have provided valuable insights into the spontaneous chemical genesis of life, there remains a significant gap in the theoretical understanding of the complex reaction processes involved. In this study, we propose a novel approach using a roto-translationally invariant potential (RTIP) formulated with pristine Cartesian coordinates to facilitate the simulation of chemical reactions. By employing RTIP pathway sampling to explore the reactivity of primitive molecules, we identified several low-energy reaction mechanisms, such as two-hydrogen-transfer hydrogenation and HCOOH-catalyzed hydration and amination. This led to the construction of a comprehensive reaction network, illustrating the synthesis pathways for glycine, serine, and alanine. Further thermodynamic analysis highlights the pivotal role of formaldimine as a key precursor in amino acid synthesis, owing to its more favorable reactivity in coupling reactions compared to the traditionally recognized hydrogen cyanide. Our study demonstrates that the RTIP methodology, coupled with a divide-and-conquer strategy, provides new insights into the simulation of complex reaction processes, offering promising applications for advancing organic design and synthesis.

Fracture patterns in bicycle accidents: A descriptive national cohort study of fractures sustained in bicycle accidents in the Swedish Fracture Register 2015–2022

Bicycle accidents account for the majority of traffic-related accidents in Sweden. Despite the widespread everyday use of bicycles, little is known about the fracture panorama resulting from bicycle accidents. This study analysed the fracture patterns of bicycle accidents in Sweden in regard to fracture type, sex, age, and type of bicycle. We retrieved data from the Swedish Fracture Register on all fractures caused by bicycle accidents between 2015 and 2022. The study population was comprised of both children and adults who had sustained one or more fractures in a bicycle accident as registered in the Swedish Fracture Register. We included 33,384 fractures (25,960 in adults and 7424 in children) in 30,815 patients, with a dominance of fractures in men. The mean age at fracture was 41.6 years (SD 23). The majority of fractures (62.7 %, n = 20,932) were sustained via a low energy mechanism. Overall, the most commonly fractured body parts were the forearm (35.2 %, n = 11,747), the hand (15.6 %, n = 5,196) and the clavicle (13.7 %, n = 4,558). In children, fractures of the forearm (56.8 %, n = 4,215) clearly dominated, followed by the hand (11.7 %, n = 868), and the humerus (11.0 %, n = 816). In adults, the top 3 fracture locations were the forearm (29.0 %, n = 7,532), the hand (16.7 %, n = 4,328), and the clavicle (15.7 %, n = 4,086). Mountain bikes and road bikes showed a fracture panorama that was very similar with a predominance of fractures to the clavicle. Fractures were more common during the warm season. The main finding is that bicyclists predominantly sustained fractures of the upper limb via low energy mechanisms. The fracture panorama differed by age, sex, and type of bicycle.

Sacral U-type Fractures in Patients Older Than 65 years.

The purpose of this study was to determine the degree of disability that geriatric patients with sacral U-type fractures experience. Patients older than 65 years presenting from 2013 to 2019 with a U-type sacral fracture were included. Patient demographics, treatment type, preinjury domicile, preinjury use of assistive devices, and neurologic deficits were recorded. Outcomes included mortality, return to preinjury domicile, and use of assistive devices for mobility. Among 46 patients in the treatment period, ground-level fall was the most common mechanism of injury (60.8%). Thirty-four patients (74%) were treated surgically, most commonly with closed percutaneous fixation (n = 27). Thirteen percent of patients died during the admission. At the final follow-up, 14 (45%) had not returned to their prior domicile and 18 (58%) required more supportive assistive devices. Seventy-three percent of patients who presented delayed required a new gait aid, compared with 47% presenting acutely. Between those presenting with low-energy versus high-energy mechanisms, similar rates of need were observed for new assistive devices (50% low and 73% high) and lack of return to preinjury domicile (40% low, 50% high). Many geriatric patients were disabled by or died after sustaining a sacral U-type fracture, highlighting the morbidity regardless of high-energy or low-energy trauma.

Spine injuries among severely injured trauma patients: A retrospective single-center cohort study.

We aimed to determine the incidence and severity of spine injuries among severely injured trauma patients (Injury Severity Score (ISS)/New Injury Severity Score (NISS) > 15) treated in a single tertiary trauma center over 15 years. We also wanted to compare the demographics between patients with and without spine injuries and to determine the mortality of spine-injury patients. Data from the years 2006-2020 from the Helsinki Trauma Registry (HTR), a local trauma registry of the trauma unit of the Helsinki University Hospital (HUH), were reviewed. We divided patients into two groups, namely those with traumatic spine injury (TSI) and those without traumatic spine injury (N-TSI). TSI patients were further subdivided into groups according to the level of injury (cervical, thoracolumbar, or multilevel) and the presence of neurological symptoms. We included 2529 patients: 1336 (53%) had a TSI and 1193 (47%) had N-TSI. TSI patients were injured more frequently by a high-fall mechanism (37% vs 21%, p < 0.001). Among TSI patients, 38% of high-fall injuries were self-inflicted. High falls, young age, and female gender were overrepresented in spine-injury patients with a self-inflicted injury mechanism. Cervical spine-injury patients were mostly elderly persons injured by a low-energy mechanism. Unlike other severely injured trauma patients, severely injured trauma patients with spine injuries are more frequently injured by a high-fall mechanism and self-injury.

Orthoplastics Management of Open Lower Limb Fractures at a Major Trauma Centre: Audit of Adherence to BOAST4 Guidelines

The British Orthopaedic Association Standards for Trauma and Orthopaedics (BOAST) guide the optimal management of open lower limb fractures. Adherence of the newly established Orthoplastic service at the Major Trauma Centre covering the Southeast of England was audited in relation to these standards. Audit standards were produced. Data were collected using hospital records and the Trauma Audit and Research Network database. All open lower limb fractures managed between August 2020-August 2022 were included. Data collected included patient and injury demographics, and information related to initial and definitive management. Overall, 133 patients were identified, 70 men and 63 women, with an average age of 58 years. Women had a higher average age (69 years) and ASA grade (71% ASA 3 or higher). Low-energy injuries occurred in 69% of women compared to 78% of high-energy injuries in men (p<0.001). Among them, 108 (81%) were debrided within 24 h. The average time to first debridement was 18.78 h, and 95 (75%) were definitively closed within 72 h, 76 with primary closure, 7 with split-thickness skin graft, 7 with local flap and 36 with free flap. Overall, the post-operative infection rate was 13% with 94% of these fractures definitively closed within 72 h. Most open lower limb fractures occurred in older women with higher ASA grade, from low-energy mechanisms. Most injuries were definitively managed as per the BOAST guidelines, but further efforts are required to improve the adherence to initial debridement targets, including training, appropriate resource allocation and implementation of procedures and proformas to guide injury management and improve documentation.

Outcomes After Implementation of a Fragility Fracture Pathway in Ground Level Falls

Fragility fractures occur due to low energy mechanisms and result in significant morbidity and mortality. This study reviews the implementation of a fragility fracture program at a level I trauma center. In this pathway, trauma surgery provides clearance followed by admission and management with medical service and orthopedic consultation for injuries which meet fragility fracture criteria. This pathway, implemented in July 2021, includes patients with isolated fractures secondary to a low energy mechanism. We compared cohorts 2-ys before (PRE) and after (POS) pathway implementation. Demographics (age, sex, fracture location, injury severity score, American Society of Anesthesiologists score) and outcome data were collected and analyzed using between-subjects analyses. Measured outcomes included deep vein thrombosis/pulmonary embolism, hospital mortality, disposition to hospice, nonoperative rate, unplanned intensive care unit admission, time to surgery (TTS), and length of stay (LOS). The study included n=1137 patients (n=564 PRE and n=573 POS). POS patients had a higher injury severity score (P=0.003) and different fracture location (P=0.017), but no other demographics were different. Trauma admission decreased after implementation (P<0.001; PRE: 21.5%, POS: 1.8%) with no differences in outcomes except increases in LOS (P<0.001; PRE: 114h, POS: 124h) and TTS (P<0.001; PRE: 15h, POS: 18h). Morbidity and mortality did not correlate with pathway implementation; however, TTS and LOS increased. Although TTS increased, it remained under the American Academy of Orthopedic Surgery 48-h recommendation. The TTS and LOS increases were potentially from COVID-19 or cohort demographic differences. Decreased trauma as admitting service demonstrates pathway adherence. These findings highlight the need for investigation to better understand fragility fracture pathways.

Management of Femoral and Tibial Shaft Fractures in Chronic Spinal Cord Injury Patients.

To compare outcomes and complications between non-operative and operative management of femur and tibia fractures in patients with paraplegia or quadriplegia from chronic spinal cord injury (SCI). Design: Retrospective cohort study. Three Level-1 Trauma centers. All adult patients with paraplegia or quadriplegia due to a chronic SCI with operative or nonoperative treatment of a femoral or tibial shaft fracture from 01/01/2009 through 12/31/2019 were included. Outcomes collected included range of motion, pain, return to baseline activity, extent of malunion and treatment complications (infection, pressure ulcers, nonunion, DVT/PE, stroke, amputation, death). Comparison between operative and nonoperative treatment were made for each outcome. Fifty-nine patients with acute lower extremity fracture in the setting of chronic SCI fulfilled inclusion criteria with a median age of 46 years in the operative group and 47 years in the non-operative group. Twelve patients (70.6%) in the nonoperative group were male with 32 (76.2%) male patients in the operative group. Forty-six patients (78%) presented as low energy trauma. Differences were seen between operative and non-operative management for pressure ulcers (19% vs 52.9%, p=0.009) and mean VAS pain score at first follow-up (1.19 vs 3.3, p=0.03). No difference was seen for rates of infection, nonunion, DVT/PE, stroke, amputation, death, return to baseline activity, and range of motion. Tibial and femoral shaft fractures commonly resulted from low energy mechanisms in patients with chronic SCI. Operative treatment seemed to decrease morbidity in these patients via lowered rates of pressure ulcers and decreased pain compared to non-operative management. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Prevalence of pelvic CT angiography (CTA) and angiographic embolization in geriatric patients with pelvic ring fractures presenting to two level I trauma centers

Hemorrhage in osteoporotic pelvic ring fractures is a rare, but serious complication. Most bleeding comes from the bone or venous plexuses, but arterial injury does occur. The purpose of this study was to characterize a large geriatric pelvic fracture cohort and determine the prevalence of pelvic CT angiography (CTA) and subsequent need for arterial embolization. A cohort of geriatric pelvic fracture patients at two level 1 trauma centers was reviewed. Many epidemiologic and patient factors were collected for cohort characterization. The primary outcome was if patients underwent a CTA of the pelvis and subsequently underwent arterial embolization. There were 457 patients included and mean age was 83.1 years (range 65-100). Most patients had a low energy mechanism (91.4 %). In-hospital mortality was recorded for 30 cases (6.6 %). Of these deaths, two received a pelvic CTA and two had an embolization procedure. Pelvic CTA was performed on 33 patients (7.2 %). Fourteen patients (3.0 %) had an arterial embolization procedure. A high energy mechanism of injury was associated with receiving a pelvic CTA (p = 0.0067). Mechanism of injury was not associated with undergoing an embolization procedure (p = 0.685). In the geriatric population, even patients with stable pelvic fractures can present with life-threatening arterial bleeding. A non-insignificant percentage of patients will require CTA for suspected bleeding (7.2 %) and embolization to treat confirmed arterial bleeding (3.0 %). Bleeding events in geriatric pelvic ring injuries is a previously under researched area of orthopedic trauma. Further research is needed to elucidate the exact pathomechanisms of arterial injury and what patients or injury patterns are most significantly associated. Specifically, larger cohort sizes and evaluating our existing cohort with different injury classification systems may yield useful results.

Cervical collars: key considerations around their use

The UK has an ageing population, and an increase in the number of injuries sustained from low energy mechanisms, such as falls. The literature identifies a number of key issues which should be considered in the care of any individual being treated with a cervical collar, impacting on how this patient group should be cared for. It is important for there to be effective communication across the multidisciplinary team to address some of these key risks and to help prevent complications. Nurses must also ensure that regular patient assessment is carried out, especially in terms of skin and pain. Any professional caring for this patient group must be adequately trained in the elements of care required from them. While cervical collars are still being used in some settings, there is suggestion that the risks outweigh the benefits of a cervical collar, with some clinical settings no longer using them anymore.

Proximal humeral fractures: association between displacement and fatty degeneration of the supraspinatus muscle.

To evaluate the relationship between initial displacement in proximal humeral fractures and fatty degeneration of the rotator cuff measured by CT according to the Goutallier classification. This cross-sectional observational study evaluated patients with proximal humeral fractures over a six-month period. The study included patients ≥ 18 years old with complete radiological views (anteroposterior, lateral, and Grashey) and a CT scan of the affected shoulder; previous fracture or ipsilateral shoulder surgery were excluded. Neer's classification system and Goutallier stages were used to evaluate the patients. Demographic data were collected and, two groups were analysed according to age (≤ 50 years and > 50 years). Sixty-two patients were included (m = 36, f = 26, ratio 1.3:1); seven patients were excluded. Male patients (36, 58.1%), patients older than 50 years (33, 53.2%) and a low-energy injury mechanism (36, 58.1%) were the most frequent cases. According to the Neer system, the most common proximal humerus fracture was fracture-dislocation in 17 (27.4%) cases. The most common stage in Goutallier's classification was I (some fatty streaks) in 22 (35.4%) cases. Younger patients (≤ 50 years) had more displaced fractures with low fatty degeneration (p = < 0.001) than older patients (> 50 years), who had minimally displaced fractures with greater fatty degeneration (p = 0.567). High-energy mechanisms are associated with younger patients and a more displaced fracture according to the Neer classification. Older patients had a more advanced Goutallier stage and lesser displaced fracture. We should consider a more aggressive approach in the treatment of non-displaced fractures in elderly patients, less conservative and more surgical management, to obtain a better clinical evolution after the treatment of these kinds of fractures. IV.

THE NATIONAL PROSTHETIC HIP DISLOCATION (PHD) STUDY

Total Hip Arthroplasty (THA) and Hip Hemiarthroplasties (HA) are successful, cost-effective procedures that improve quality of life. Dislocation is a well recognised complication with a significant health and economic burden. We aim to establish the current management practices across the United Kingdom (UK) for Prosthetic Hip Dislocations (PHD). Our definition of a PHD includes; THA, HA and revision THA.This national study builds on our regional pilot study and records one of the largest datasets of Prosthetic Hip Dislocation management within the UK.A trainee-led collaborative; the North West Orthopaedic Research Collaborative (NWORC). Conducted a retrospective audit, registered as Quality Improvement (QI) projects, collected data from 38 hospital trusts across the UK.Data was collected on patient-related factors, inpatient management, and outpatient follow up of each PHD episode between January and July 2019. Primary outcome measured definitive management, in the form of revision surgery or the consideration for this through a referral pathway.A total of 673 (THA 504, Revision THA 141, HA 28) patients were included with a total of 740 dislocation episodes. Mean age was 75.6 years with female to male ratio 2:1. The majority of PHDs were a result of a low energy mechanism (98.7%) and presented over 6 months post index procedure (80.5%). Over half (53.8%) attended with a first or second time dislocation. Only 29.9% patients received onward revision referral; whereas 70.1% followed diverse management patterns, including local non-arthroplasty and primary arthroplasty surgeon follow-ups. Revision THAs had higher rates of referral for revision (p&lt;0.001) compared to primary THA and HA dislocations.A high number of PHDs present across the UK, with under a third receiving definitive management plans. This variation increases the economical burden to the National Health Service, highlighting the need for national guidance to manage these complex patients.

Atlantoaxial trauma

Atlantoaxial trauma

The Association between Race and Extended Length of Stay in Low-energy Proximal Humerus Fractures in Elderly Patients.

Proximal humerus fractures (PHFs) are one of the most common fractures among patients aged 65 years and older, commonly due to low-energy mechanisms. It is essential to identify drivers of increased healthcare utilization in geriatric PHF patients and bring awareness to any disparities in care. Here, we identify factors associated with the likelihood of inpatient admission and prolonged hospital stay among patients aged 65 years and older who sustain PHF due to falls. A national database was used to identify patients aged 65 years and older who suffered proximal humeral fractures due to a fall. Patient factors were analyzed for association with the likelihood of admission and odds of prolonged stay (≥5 days). In the study period, 75,385 PHF patients who met our inclusion criteria presented to the emergency department and 14,118 (18.7%) were admitted. Black race was significantly associated with decreased odds of admission ( P < 0.001) and increased likelihood of prolonged stay ( P = 0.007) compared with White patients. Patients aged 75 to 84 and 85+ were both more likely to be admitted ( P < 0.001) and experienced a prolonged hospital stay ( P = 0.015). Patients undergoing surgical intervention with reverse total shoulder arthroplasty were associated with admission and prolonged length of stay ( P < 0.001). Hospitals in Midwestern ( P < 0.001) and Western ( P < 0.001) regions exhibited lower rates of admission and Northeastern hospitals were associated with prolonged stays ( P = 0.001). Finally, trauma and nonmetropolitan ( P < 0.001) centers were associated with admission. Our study highlights the notable influence of age and race on the likelihood of hospital admission and prolonged hospital stay. Specifically, Black patients exhibited prolonged hospital stay, which has been associated with lower-quality care, warranting additional exploration. Understanding these demographic and hospital-related factors is essential for optimizing resource allocation and reducing healthcare disparities in the care of PHF patients, especially as the population ages and the incidence of PHF continues to rise.

Proximal Tibia Fracture Through Suture Augmentation Sites Following ACL/MCL Repairs: A Case Report.

A 35-year-old man sustained a proximal tibia fracture from a low-energy mechanism 1 year after anterior cruciate and medial collateral ligament repairs with suture augmentation (SA). The fracture propagated through both tibial SA anchor sites. Following intramedullary tibial nailing, he returned to his prior level of function. While complications of SA for ligamentous procedures are rare, these techniques are being implemented more frequently and the full complication profile is yet to be determined. Our report documents a new complication and potential risk factors that surgeons should consider when performing SA for multiligament knee surgery in active individuals.

Two adolescents with chest pain after low-energy mechanisms.

Two adolescents with chest pain after low-energy mechanisms.