Clinical Focus

  • Orthopaedic Surgery
  • Sports Medicine
  • Emergency Medicine

Academic Appointments

Administrative Appointments

  • Team Physician, San Francisco 49ers (2013 - 2014)
  • Team Physician, Stanford Football (2013 - 2014)
  • Team Physician, Stanford Women's Soccer (2013 - 2014)

Honors & Awards

  • Outstanding Researcher Award, Harvard Affiliated Emergency Medicine Residency (2013)
  • Hauser Fellowship, Harvard University (2009)
  • Phi Beta Kappa, Alpha Chapter of Yale University (2004)
  • Wohlenberg Prize, Yale University (2004)
  • Richter Research Fellowship, Yale University (2003)
  • Yale College Dean's Research Fellowship, Yale University (2003)
  • MIchael Manzella Fellowship, Yale University (2002)
  • J.W. Saxe Memorial Prize, Yale University (2002)

Professional Education

  • M.D., Stanford University School of Medicine, Medicine (2010)
  • M.P.H., Harvard School of Public Health, Global and Population Health (2010)
  • B.S., Yale University, Psychology; Molecular Biology (2004)
  • Residency, Harvard Affiliated Emergency Medicine Residency, Emergency Medicine (2013)
  • Fellowship, Stanford Sports Medicine Fellowship, Sports Medicine (2014)
  • Medical Education:Stanford Medical Center (2010) CA
  • Residency:Beth Israel Deaconess Medical Center (2013) MA
  • Internship:Beth Israel Deaconess Medical Center (2011) MA


Journal Articles

  • Early Screening for Cardiovascular Abnormalities With Preparticipation Echocardiography Utility of Focused Physician-Operated Echocardiography in Preparticipation Screening of Athletes JOURNAL OF ULTRASOUND IN MEDICINE Yim, E. S., Basilico, F., Corrado, G. 2014; 33 (2): 307-313


    Objectives- We have developed the Early Screening for Cardiovascular Abnormalities With Preparticipation Echocardiography protocol to improve false-positive rates, reduce referrals, and broaden the spectrum of disease that can be captured through preparticipation screening of athletes. This study documents the first application of this protocol and uses case analysis to discuss the potential utility of portable sonography in screening. Methods- Sixty-five male collegiate athletes, aged 18 to 25 years, were prospectively enrolled. Each athlete was screened with a history and physical examination, electrocardiography (ECG), and focused echocardiography performed by a noncardiologist sports medicine physician. The history and physical examination were based on the 12-element American Heart Association recommendations; 2010 European Society of Cardiology criteria were used to screen ECGs. Focused physician-operated echocardiography was performed to assess for hypertrophic cardiomyopathy and aortic root dilatation. Athletes screening positive were referred to a cardiologist. Results- Most of the athletes (n = 59) did not screen positive by any screening modality. Three athletes screened positive on ECG but had normal focused echocardiographic findings. Three athletes screened positive by history and physical examination but had normal ECG and focused echocardiographic findings. All athletes screening positive were referred to a cardiologist and eventually cleared for sports participation. No athlete screened positive by focused echocardiography alone. Focused echocardiography was able to reduce the referral rate for hypertrophic cardiomyopathy by 33% and obtained measurements statistically similar to those of formal echocardiography. Conclusions- This study provides evidence that focused physician-operated echocardiography can improve false-positive rates and broaden the spectrum of disease that is detectable through preparticipation screening of athletes.

    View details for DOI 10.7863/ultra.33.2.307

    View details for Web of Science ID 000330604700015

    View details for PubMedID 24449734

  • Focused physician-performed echocardiography in sports medicine: a potential screening tool for detecting aortic root dilatation in athletes. Journal of ultrasound in medicine Yim, E. S., Kao, D., Gillis, E. F., Basilico, F. C., Corrado, G. D. 2013; 32 (12): 2101-2106


    Objectives- The purpose of this study was to investigate whether sports medicine physicians can obtain accurate measurements of the aortic root in young athletes. Methods- Twenty male collegiate athletes, aged 18 to 21 years, were prospectively enrolled. Focused echocardiography was performed by a board-certified sports medicine physician and a medical student, followed by comprehensive echocardiography within 2 weeks by a cardiac sonographer. A left parasternal long-axis view was acquired to measure the aortic root diameter at the sinuses of Valsalva. Intraclass correlation coefficients (ICCs) were used to assess inter-rater reliability compared to a reference standard and intra-rater reliability of repeated measurements obtained by the sports medicine physician and medical student. Results- The ICCs between the sports medicine physician and cardiac sonographer and between the medical student and cardiac sonographer were strong: 0.80 and 0.76, respectively. Across all 3 readers, the ICC was 0.89, indicating strong inter-rater reliability and concordance. The ICC for the 2 measurements taken by the sports medicine physician for each athlete was 0.75, indicating strong intra-rater reliability. The medical student had moderate intra-rater reliability, with an ICC of 0.59. Conclusions- Sports medicine physicians are able to obtain measurements of the aortic root by focused echocardiography that are consistent with those obtained by a cardiac sonographer. Focused physician-performed echocardiography may serve as a promising technique for detecting aortic root dilatation and may contribute in this manner to preparticipation cardiovascular screening for athletes.

    View details for DOI 10.7863/ultra.32.12.2101

    View details for PubMedID 24277891

  • Aortic Root Disease in Athletes: Aortic Root Dilation, Anomalous Coronary Artery, Bicuspid Aortic Valve, and Marfan's Syndrome SPORTS MEDICINE Yim, E. S. 2013; 43 (8): 721-732


    Two professional athletes in the U.S. National Basketball Association required surgery for aortic root dilation in 2012. These cases have attracted attention in sports medicine to the importance of aortic root disease in athletes. In addition to aortic root dilation, other forms of aortic disease include anomalous coronary artery, bicuspid aortic valve, and Marfan's syndrome. In this review, electronic database literature searches were performed using the terms "aortic root" and "athletes." The literature search produced 122 manuscripts. Of these, 22 were on aortic root dilation, 21 on anomalous coronary arteries, 12 on bicuspid aortic valves, and 8 on Marfan's syndrome. Aortic root dilation is a condition involving pathologic dilation of the aortic root, which can lead to life-threatening sequelae. Prevalence of the condition among athletes and higher risk athletes in particular sports needs to be better delineated. Normative parameters for aortic root diameter in the general population are proportionate to anthropomorphic variables, but this has not been validated for athletes at the extremes of anthropomorphic indices. Although echocardiography is the favored screening modality, computed tomography (CT) and cardiac magnetic resonance imaging (MRI) are also used for diagnosis and surgical planning. Medical management has utilized beta-blockers, with more recent use of angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), and statins. Indications for surgery are based on comorbidities, degree of dilation, and rate of progression. Management decisions for aortic root dilation in athletes are nuanced and will benefit from the development of evidence-based guidelines. Anomalous coronary artery is another form of aortic disease with relevance in athletes. Diagnosis has traditionally been through cardiac catheterization, but more recently has included evaluation with echocardiography, multislice CT, and MRI. Athletes with this condition should be restricted from participation in competitive sports, but can be cleared for participation 6 months after surgical repair. Bicuspid aortic valve is another form of aortic root disease with significance in athletes. Although echocardiography has traditionally been used for diagnosis, CT and MRI have proven more sensitive and specific. Management of bicuspid aortic valve consists of surveillance through echocardiography, medical therapy with beta-blockers and ARBs, and surgery. Guidelines for sports participation are based on the presence of aortic stenosis, aortic regurgitation, and aortic root dilation. Marfan's syndrome is a genetic disorder with a number of cardiac manifestations including aortic root dilation, aneurysm, and dissection. Medical management involves beta-blockers and ARBs. Thresholds for surgical management differ from the general population. With regard to sports participation, the most important consideration is early detection. Athletes with the stigmata of Marfan's syndrome or with family history should be tested. Further research should determine whether more aggressive screening is warranted in sports with taller athletes. Athletes with Marfan's syndrome should be restricted from activities involving collision and heavy contact, avoid isometric exercise, and only participate in activities with low intensity, low dynamic, and low static components. In summary, many forms of aortic root disease afflict athletes and need to be appreciated by sports medicine practitioners because of their potential to lead to tragic but preventable deaths in an otherwise healthy population.

    View details for DOI 10.1007/s40279-013-0057-6

    View details for Web of Science ID 000322033400007

    View details for PubMedID 23674060

  • Focused transthoracic echocardiography by sports medicine physicians: measurements relevant to hypertrophic cardiomyopathy. Journal of ultrasound in medicine Yim, E. S., Gillis, E. F., Ojala, K., MacDonald, J., Basilico, F. C., Corrado, G. D. 2013; 32 (2): 333-338


    The purpose of this study was to investigate whether sports medicine physicians can use portable echocardiography to obtain measurements pertinent to hypertrophic cardiomyopathy.Thirty male collegiate athletes, aged 18 to 21 years, were prospectively enrolled. Focused portable echocardiography was performed by a board-certified sports medicine physician and a resident physician, followed by comprehensive echocardiography within 2 weeks by a registered diagnostic cardiac sonographer. A left parasternal long-axis view was acquired to measure 3 dimensions: (1) end-diastolic interventricular septal thickness (IVSd), (2) end-diastolic left ventricular internal diameter (LVIDd), and (3) end-diastolic left ventricular posterior wall thickness (LVPWd).Intraclass correlation coefficients between the sports medicine physician and the sonographer were strong: 0.77 for IVSd, 0.73 for LVIDd, and 0.64 for LVPWd. Intraclass correlation coefficients between measurements by the resident physician and sonographer were strong to moderate: 0.61 for IVSd, 0.62 for LVIDd, and 0.63 for LVPWd. Across all 3 readers, intraclass correlation coefficient calculations were 0.77 for IVSd, 0.81 LVIDd, and 0.75 for LVPWd, which indicated strong inter-rater reliability.Sports medicine physicians are able to obtain measurements relevant to the diagnosis of hypertrophic cardiomyopathy with focused portable echocardiography that are consistent with comprehensive echocardiography by a registered sonographer.

    View details for PubMedID 23341391

  • Case Report: Lower Extremity Deep Vein Thrombosis Following an Intense Calf Workout CURRENT SPORTS MEDICINE REPORTS Yim, E. S., Friedberg, R. P. 2012; 11 (6): 282-286


    We report a case of a high-performance athlete with hemoglobin SC who presented with asymmetric calf soreness after an intense calf workout. By ultrasonography, he was diagnosed with a deep vein thrombosis (DVT) of his right calf. Subsequently he presented with a number of sequelae of sickle cell disease: acute chest syndrome, avascular necrosis of the hips, and chronic kidney disease. The case is instructive as an example of DVT after exercise of the lower extremities, which has not been documented well. The case also illustrates a number of health sequelae of sickle cell disease that mimic more common musculoskeletal complaints. Sports medicine providers will have to consider these uncommon but profound diagnostic entities when caring for athletes with sickle cell disease. The case further highlights how research can inform the clinical decisions and policies aimed at reducing the risk of life-threatening and lifelong sequelae of sickle cell disease in athletes.

    View details for DOI 10.1249/JSR.0b013e318272c331

    View details for Web of Science ID 000311027800003

    View details for PubMedID 23147014

  • Ultrasound in Athletes: Emerging Techniques in Point-of-Care Practice CURRENT SPORTS MEDICINE REPORTS Yim, E. S., Corrado, G. 2012; 11 (6): 298-303


    Ultrasound offers sports medicine clinicians the potential to diagnose, treat, and manage a broad spectrum of conditions afflicting athletes. This review article highlights applications of ultrasound that hold promise as point-of-care diagnostics and therapeutic tools that can be used directly by clinicians to direct real-time management of athletes. Point-of-care ultrasound has been examined most in the context of musculoskeletal disorders in athletes, with attention given to Achilles tendinopathy, patellar tendinopathy, hip and thigh pathology, elbow tendinopathy, wrist pathology, and shoulder pain. More research has focused on therapeutic applications than diagnostic, but initial evidence has been generated in both. Preliminary evidence has been published also on abdominal ultrasound for splenic enlargement in mononucleosis, cardiopulmonary processes and hydration status, deep vein thrombosis, and bone mineral density. Further research will be required to validate these applications and to explore further applications of portable ultrasound that can be used in the care of athletes.

    View details for DOI 10.1249/JSR.0b013e318272c89b

    View details for Web of Science ID 000311027800006

    View details for PubMedID 23147017


    View details for Web of Science ID 000306729100020

    View details for PubMedID 22494601

  • Integrating the Disaster Cycle Model Into Traditional Disaster Diplomacy Concepts DISASTER MEDICINE AND PUBLIC HEALTH PREPAREDNESS Callaway, D. W., Yim, E. S., Stack, C., Burkle, F. M. 2012; 6 (1): 53-59


    Disaster diplomacy is an evolving contemporary model that examines how disaster response strategies can facilitate cooperation between parties in conflict. The concept of disaster diplomacy has emerged during the past decade to address how disaster response can be leveraged to promote peace, facilitate communication, promote human rights, and strengthen intercommunity ties in the increasingly multipolar modern world. Historically, the concept has evolved through two camps, one that focuses on the interactions between national governments in conflict and another that emphasizes the grassroots movements that can promote change. The two divergent approaches can be reconciled and disaster diplomacy further matured by contextualizing the concept within the disaster cycle, a model well established within the disaster risk management community. In particular, access to available health care, especially for the most vulnerable populations, may need to be negotiated. As such, disaster response professionals, including emergency medicine specialists, can play an important role in the development and implementation of disaster diplomacy concepts.

    View details for Web of Science ID 000302781800009

    View details for PubMedID 22490937

  • Ultrasound in Sports Medicine Relevance of Emerging Techniques to Clinical Care of Athletes SPORTS MEDICINE Yim, E. S., Corrado, G. 2012; 42 (8): 665-680


    The applications of ultrasound in managing the clinical care of athletes have been expanding over the past decade. This review provides an analysis of the research that has been published regarding the use of ultrasound in athletes and focuses on how these emerging techniques can impact the clinical management of athletes by sports medicine physicians. Electronic database literature searches were performed using the subject terms 'ultrasound' and 'athletes' from the years 2003 to 2012. The following databases were searched: PubMed, Web of Science, Cochrane Library, CINAHL, and SPORTDiscus™. The search produced 617 articles in total, with a predominance of articles focused on cardiac and musculoskeletal ultrasound. 266 of the studies involved application of ultrasound in evaluating the cardiovascular properties of athletes, and 151 studies involved musculoskeletal ultrasound. Other applications of ultrasound included abdominal, vascular, bone density and volume status. New techniques in echocardiography have made significant contributions to the understanding of the physiological changes that occur in the athlete's heart in response to the haemodynamic stress associated with different types of activity. The likely application of these techniques will be in managing athletes with hypertrophic cardiomyopathy, and the techniques are near ready for application into clinical practice. These techniques are highly specialized, however, and will require referral to dedicated laboratories to influence the clinical management of athletes. Investigation of aortic root pathology and pulmonary vascular haemodynamics are also emerging, but will require additional studies with larger numbers and outcomes analysis to validate their clinical utility. Some of these techniques are relatively simple, and thus hold the potential to enter clinical management in a point-of-care fashion. Musculoskeletal ultrasound has demonstrated a number of diagnostic and therapeutic techniques applicable to pathology of the shoulder, elbow, wrist, hand, hip, knee and ankle. These techniques have been applied mainly to the management of impingement syndromes, tendinopathies and arthritis. Many of these techniques have been validated and have entered clinical practice, while more recently developed techniques (such as dynamic ultrasound and platelet-rich plasma injections) will require further research to verify efficacy. Research in musculoskeletal ultrasound has also been helpful in identifying risk factors for injury and, thus, serving as a focus for developing interventions. Research in abdominal ultrasound has investigated the potential role of ultrasound imaging in assessing splenomegaly in athletes with mononucleosis, in an attempt to inform decisions and policies regarding return to play. Future research will have to demonstrate a reduction in adverse events in order to justify the application of such a technique into policy. The role of ultrasound in assessing groin pain and abdominal pain in ultraendurance athletes has also been investigated, providing promising areas of focus for the development of treatment interventions and physical therapy. Finally, preliminary research has also identified the role of ultrasound in addressing vascular disease, bone density and volume status in athletes. The potential applications of ultrasound in athletes are broad, and continuing research, including larger outcome studies, will be required to establish the clinical utility of these techniques in the care of athletes.

    View details for Web of Science ID 000307323100003

    View details for PubMedID 22712843

  • Long-term follow-up of the surgical management of neuropathic arthropathy of the spine. spine journal Haus, B. M., Hsu, A. R., Yim, E. S., Meter, J. J., Rinsky, L. A. 2010; 10 (6): e6-e16


    No studies have discussed the long-term surgical management and outcomes of Charcot arthropathy of the spine. This case series presents nine patients treated over 30 years. The study hypothesis was that surgery would reduce instability, pain, recurrence, and the need for revision surgery in the long-term, given previous study findings of successful fusion of Charcot spine in the short-term.To evaluate the long-term outcomes of surgery for Charcot spine.Retrospective case series. Cases took place at Stanford University Medical Center and Santa Clara Valley Medical Center.All patients had either complete paraplegia or dense paraparesis with both major motor and sensory deficits. Seven patients developed Charcot spine after spinal instrumentation for trauma, one after scoliosis repair for meningomyelocele, and one after spinal instrumentation for neuromuscular scoliosis caused by birth injury resulting in C6-C7 quadraplegia. Average time between initial instrumentation and development of Charcot spine was 7.6 years. Two patients underwent posterior fusion alone, six had anterior-posterior fusion, and one was managed with thoracolumbar orthosis.Average follow-up was 14.3 years. Revisions were necessary in 75% (6 of 8) of patients for complications including nonunion, new Charcot joints, recurrent hardware failure, and osteomyelitis. Achieving fusion often required multiple operations, and there were no deaths or neurologic complications.Long-term follow-up showed a high rate of revision surgery. Solid fusions often resulted in late breakdown or new junctional Charcot arthropathies. Patients initially fused to the lumbar spine instead of the sacrum or pelvis had a higher rate of developing another Charcot joint. Fusion was often difficult with persistent nonunions and functional deficits because of decreased mobility. We recommend that Charcot spine well tolerated without skin, seating problems, or dysreflexia should be cautiously observed with conservative management. For surgical care, we recommend three-column stabilization with either combined anterior-posterior or all posterior approaches with anterior support to obtain and secure greater long-term stability.

    View details for DOI 10.1016/j.spinee.2010.03.030

    View details for PubMedID 20494808

  • Biocompatibility of poly(ethylene glycol)/poly(acrylic acid) interpenetrating polymer network hydrogel particles in RAW 264.7 macrophage and MG-63 osteoblast cell lines. Journal of biomedical materials research. Part A Yim, E. S., Zhao, B., Myung, D., Kourtis, L. C., Frank, C. W., Carter, D., Smith, R. L., Goodman, S. B. 2009; 91 (3): 894-902


    Hydrogel polymers comprise a novel category of synthetic materials being investigated for use in cartilage replacement. One candidate compound, a poly(ethylene glycol)/poly(acrylic acid) (PEG/PAA) interpenetrating polymer network (IPN), was developed for use in corneal prostheses and was recently engineered for potential orthopedic use. The current study examined the effects of particles of this compound on two cell lines (MG-63 osteoblast-like cells and RAW 264.7 macrophages) over a 48-h time course. To mimic the effects of wear debris, particles of the compound were generated and introduced to the cells. In the MG-63 cell line, the particles had no significant effect on cell viability measured by PicoGreen assay and trypan blue exclusion. In contrast, a significant decrease in cell viability was detected in the Raw 264.7 macrophage cells at the final timepoint with the highest concentration of hydrogel (3.0% v:v). A concentration- and time-dependent increase in TNF-alpha release characteristic of other known biocompatible materials was also detected in RAW 264.7 cells, but nitric oxide and interleukin (IL)-1beta showed no response. In addition, the MG-63 cell line demonstrated no IL-6 response. Particles of the PEG/PAA IPN thus seem to stimulate biological responses similar to those in other biocompatible materials.

    View details for DOI 10.1002/jbm.a.32311

    View details for PubMedID 19072924

  • Health and disaster diplomacy in North Korea: ensuring access and accountability in complex political environment. Prehospital and disaster medicine Yim, E. S., VanRooyen, M. J. 2009; 24 (4): 294-296

    View details for PubMedID 19806552

  • Maintaining health sector collaborations between United States non-governmental organizations and North Korea through innovation and planning. Prehospital and disaster medicine Yim, E. S., Choi, R. Y., VanRooyen, M. 2009; 24 (3): 153-160


    Humanitarian agencies in North Korea operate within a complex sociopolitical environment historically characterized by a baseline of mistrust. As a result of operating within such a heated environment, health sector collaborations between such agencies and the North Korean government have followed unpredictable courses.The factors that have contributed to successful programmatic collaborations, as perceived by United States non-governmental organizations (NGOs) and North Korean officials were investigated.A qualitative, multi-case, comparative, research design using semistructured interviews was used. Expert North Korean informants were interviewed to generate a list of factors contributing to programmatic success, defined as fulfilling mutually established objectives through collaboration. The North Korean informants were asked to identify US NGOs that fulfill these criteria ("mission-compatible NGOs"). Representatives from all of the mission compatible NGOs were interviewed. All informants provided their perspectives on the factors that contributed to successful programmatic collaborations. The interviews were recorded, transcribed, and analyzed for thematic content.North Korean informants identified six mission-compatible US NGOs. The North Korean and US NGO informants provided a number of factors that contributed to successful programs. These factors were grouped into the following themes: (1) responsiveness to North Korean requests; (2) resident status; (3) program monitoring; (4) sincerity (apolitical objectives); (5) information gathering; and (6) interagency collaboration.Some US NGOs have devised innovative measures to work within a unique set of parameters in North Korea. Both US NGOs and North Korean authorities have made significant concessions to maintain their programmatic partnerships. In this manner, seasoned collaborators have employed creative strategies and a form of health diplomacy to facilitate programmatic success in North Korea by building trust within a complex sociopolitical space.

    View details for PubMedID 19618349

  • North Korea halts foreign food-aid programme LANCET Yim, E. S. 2009; 373 (9673): 1416-1416

    View details for Web of Science ID 000265501900014

    View details for PubMedID 19400000

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