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(BQ) Part 1 book Diagnostic imaging - Emergency presents the following contents: Central nervous system, chest/cardiovascular, abdomen pelvis, achilles tendon tear and tendinopathy, achilles tendon tear and tendinopathy,...
Diagnostic Imaging: Emergency Editors Editors R Brooke Jeffrey MD Professor and Vice-Chairman Department of Radiology Stanford University School of Medicine Stanford, California B J Manaster MD, PhD, FACR Professor of Radiology University of Utah School of Medicine Salt Lake City, Utah Anne G Osborn MD, FACR University Distinguished Professor Professor of Radiology William H and Patricia W Child Presidential Endowed Chair in Radiology University of Utah School of Medicine Salt Lake City, Utah Melissa L Rosado-de-Christenson MD, FACR Section Chief, Thoracic Imaging Saint Luke's Hospital of Kansas City Professor of Radiology University of Missouri-Kansas City Kansas City, Missouri Contributors Andrew Sonin, MD, FACR Musculoskeletal Radiology Radiology Imaging Associates Englewood, Colorado Clinical Assistant Professor of Radiology University of Colorado School of Medicine Denver, Colorado Bryson Borg, MD Chief of Neuroradiology David Grant Medical Center Travis Air Force Base Fairfield, California Julia Crim, MD Chief of Musculoskeletal Radiology Professor of Radiology University of Missouri at Columbia Columbia, Missouri Adam C Zoga, MD Director of Musculoskeletal MRI Vice-Chair for Clinical Practice Associate Professor of Radiology Thomas Jefferson University Hospital Philadelphia, Pennsylvania Michael J Tuite, MD Vice-Chair of Operations Professor of Musculoskeletal Radiology University of Wisconsin Medical School Madison, Wisconsin Terrance T Healey, MD Diagnostic Imaging: Emergency Director, Thoracic Radiology Assistant Professor of Diagnostic Imaging Department of Diagnostic Imaging Warren Alpert Medical School of Brown University Providence, Rhode Island Carol L Andrews, MD Associate Professor Division Chief, Musculoskeletal Radiology University of Pittsburgh Medical Center Pittsburgh, Pennsylvania Gregory L Katzman, MD, MBA Associate Professor of Neuroradiology Vice-Chair of Clinical Operations Chief Quality Officer Chief Business Development Officer Department of Radiology University of Chicago Chicago, Illinois Bronwyn E Hamilton, MD Associate Professor of Radiology Neuroradiology Fellowship Co-Director Neuroradiology Division Oregon Health & Science University Portland, Oregon Michael P Federle, MD, FACR Professor and Associate Chair for Education Department of Radiology Stanford University School of Medicine Stanford, California Lane F Donnelly, MD Chief Medical Officer and Physician-in-Chief Nemours Children's Hospital Vice President and Nemours Chair of Radiology Nemours Foundation Jacksonville, Florida Professor of Radiology University of Central Florida College of Medicine Orlando, Florida Professor of Radiology Florida State University College of Medicine Tallahassee, Florida Carl Merrow, MD Staff Radiologist Cincinnati Children's Hospital Medical Center Assistant Professor of Clinical Radiology University of Cincinnati College of Medicine Cincinnati, Ohio Jonathan Hero Chung, MD Associate Professor of Radiology Director of Cardiopulmonary Imaging Fellowship Director of Radiology Professional Quality Assurance National Jewish Health Denver, Colorado Karen L Salzman, MD Diagnostic Imaging: Emergency Professor of Radiology Leslie W Davis Endowed Chair in Neuroradiology University of Utah School of Medicine Salt Lake City, Utah Michelle A Michel, MD Professor of Radiology and Otolaryngology Chief, Head and Neck Neuroradiology Medical College of Wisconsin Milwaukee, Wisconsin Christopher G Anton, MD Division Chief of Radiology Assistant Professor of Radiology and Pediatrics Cincinnati Children's Hospital Medical Center Associate Program Director University of Cincinnati Radiology Residency Cincinnati, Ohio Cheryl Petersilge, MD Clinical Professor of Radiology Cleveland Clinic Lerner College of Medicine Case Western Reserve University Cleveland, Ohio Lubdha M Shah, MD Associate Professor of Radiology Division of Neuroradiology University of Utah School of Medicine Salt Lake City, Utah Perry P Ng, MBBS (Hons), FRANZCR Assistant Professor, Department of Radiology Interventional Neuroradiologist University of Utah School of Medicine Salt Lake City, Utah Paula J Woodward, MD David G Bragg, MD and Marcia R Bragg Presidential Endowed Chair in Oncologic Imaging Professor of Radiology University of Utah School of Medicine Salt Lake City, Utah Tomás Franquet, MD, PhD Director of Thoracic Imaging Hospital de Sant Pau Associate Professor of Radiology Universidad Autónoma de Barcelona Barcelona, Spain H Christian Davidson, MD Associate Professor of Radiology University of Utah School of Medicine Salt Lake City, Utah Christine M Glastonbury, MBBS Professor of Radiology and Biomedical Imaging Otolaryngology-Head and Neck Surgery and Radiation Oncology University of California, San Francisco San Francisco, California Carol C Wu, MD Instructor of Radiology Harvard Medical School Diagnostic Imaging: Emergency Assistant Radiologist Massachusetts General Hospital Boston, Massachusetts Gary M Nesbit, MD Professor of Radiology, Neurology, Neurological Surgery, and the Dotter Interventional Institute Oregon Health & Science University Portland, Oregon Helen T Winer-Muram, MD Professor of Clinical Radiology Indiana University School of Medicine Indianapolis, Indiana John P Lichtenberger, III, MD Chief of Cardiothoracic Imaging David Grant Medical Center Travis Air Force Base Fairfield, California Assistant Professor of Radiology Uniformed Services University of the Health Sciences Bethesda, Maryland Kristine M Mosier, DMD, PhD Associate Professor of Radiology Chief, Head and Neck Radiology Indiana University School of Medicine Department of Radiology & Imaging Sciences Indianapolis, Indiana Laurie A Loevner, MD Professor of Radiology, Otorhinolaryngology, Head and Neck Surgery, Neurosurgery Perelman School of Medicine at the University of Pennsylvania Director, Head and Neck Imaging University of Pennsylvania Health System Philadelphia, Pennsylvania Miral D Jhaveri, MD Assistant Professor Director of Neuroradiology Department of Diagnostic Radiology & Nuclear Medicine Rush University Medical Center Chicago, Illinois Santiago Martínez-Jiménez, MD Associate Professor of Radiology University of Missouri-Kansas City Saint Luke's Hospital of Kansas City Kansas City, Missouri Sara M O'Hara, MD, FAAP Division Chief of Ultrasound Cincinnati Children's Hospital Medical Center Professor of Clinical Radiology and Pediatrics University of Cincinnati College of Medicine Cincinnati, Ohio Yoshimi Anzai, MD, MPH Professor of Radiology University of Washington Medical Center Seattle, Washington Alexander J Towbin, MD Diagnostic Imaging: Emergency Neil D Johnson Chair of Radiology Informatics Cincinnati Children's Hospital Medical Center Associate Professor of Clinical Radiology and Pediatrics University of Cincinnati College of Medicine Cincinnati, Ohio Andrew M Zbojniewicz, MD Staff Radiologist Cincinnati Children's Hospital Medical Center Assistant Professor of Clinical Radiology University of Cincinnati College of Medicine Cincinnati, Ohio Barton F Branstetter, IV, MD Professor of Radiology, Otolaryngology, and Biomedical Informatics University of Pittsburgh School of Medicine Chief of Neuroradiology University of Pittsburgh Medical Center Pittsburgh, Philadelphia Brett W Carter, MD Assistant Professor Department of Diagnostic Radiology Section of Thoracic Imaging The University of Texas MD Anderson Cancer Center Houston, Texas Blaise V Jones, MD Associate Director of Radiology Neuroradiology Section Chief Cincinnati Children's Hospital Medical Center Professor of Clinical Radiology and Pediatrics University of Cincinnati College of Medicine Cincinnati, Ohio Bernadette L Koch, MD Associate Director of Radiology Cincinnati Children's Hospital Medical Center Professor of Clinical Radiology and Pediatrics University of Cincinnati College of Medicine Cincinnati, Ohio Daniel J Podberesky, MD Chief of Thoracoabdominal Imaging Cincinnati Children's Hospital Medical Center Associate Professor of Clinical Radiology University of Cincinnati College of Medicine Cincinnati, Ohio Deborah R Shatzkes, MD Director of Head and Neck Imaging Lenox Hill Hospital North Shore LIJ Health Systems New York, New York Daniel B Wallihan, MD Staff Radiologist Cincinnati Children's Hospital Medical Center Assistant Professor of Clinical Radiology University of Cincinnati College of Medicine Cincinnati, Ohio Edward P Quigley, III, MD, PhD Diagnostic Imaging: Emergency Assistant Professor of Radiology Division of Neuroradiology University of Utah School of Medicine Salt Lake City, Utah Hank Baskin, MD Pediatric Imaging Section Chief Intermountain Healthcare Adjunct Assistant Professor of Radiology University of Utah School of Medicine Salt Lake City, Utah Jeffrey P Kanne, MD Associate Professor Chief of Thoracic Imaging Vice Chair of Quality and Safety Department of Radiology University of Wisconsin School of Medicine and Public Health Madison, Wisconsin James M Provenzale, MD Professor of Radiology Duke University Medical Center Durham, North Carolina Professor of Radiology, Biomedical Engineering, and Oncology Emory University School of Medicine Atlanta, Georgia Jeffrey S Ross, MD Neuroradiology Barrow Neurological Institute St Joseph's Hospital Phoenix, Arizona Amir A Borhani, MD Abdominal Imaging Fellow University of Pittsburgh Medical Center Pittsburgh, Pennsylvania Rebecca S Cornelius, MD, FACR Professor of Radiology and Otolaryngology, Head and Neck Surgery University of Cincinnati College of Medicine University of Cincinnati Medical Center Cincinnati, Ohio H Ric Harnsberger, MD Professor of Radiology and Otolaryngology R.C Willey Chair in Neuroradiology University of Utah School of Medicine Salt Lake City, Utah Roya Sohaey, MD Professor of Radiology Professor of Obstetrics and Gynecology Director of Ultrasound Oregon Health & Science University Portland, Oregon Sheri L Harder, MD, FRCPC Assistant Professor of Radiology Division of Neuroradiology Loma Linda University Medical Center Loma Linda, California Diagnostic Imaging: Emergency Diane C Strollo, MD, FACR Clinical Associate Professor University of Pittsburgh Medical Center Pittsburgh, Pennsylvania Gerald F Abbott, MD Associate Professor of Radiology Harvard Medical School Massachusetts General Hospital Boston, Massachusetts Jonathan D Dodd, MD, MSc, MRCPI, FFR(RCSI) Associate Professor of Radiology University College Dublin Director of Radiology St Vincent's University Hospital Dublin, Ireland Editors Editors R Brooke Jeffrey MD Professor and Vice-Chairman Department of Radiology Stanford University School of Medicine Stanford, California B J Manaster MD, PhD, FACR Professor of Radiology University of Utah School of Medicine Salt Lake City, Utah Anne G Osborn MD, FACR University Distinguished Professor Professor of Radiology William H and Patricia W Child Presidential Endowed Chair in Radiology University of Utah School of Medicine Salt Lake City, Utah Melissa L Rosado-de-Christenson MD, FACR Section Chief, Thoracic Imaging Saint Luke's Hospital of Kansas City Professor of Radiology University of Missouri-Kansas City Kansas City, Missouri Contributors Andrew Sonin, MD, FACR Musculoskeletal Radiology Radiology Imaging Associates Englewood, Colorado Clinical Assistant Professor of Radiology University of Colorado School of Medicine Denver, Colorado Bryson Borg, MD Chief of Neuroradiology David Grant Medical Center Travis Air Force Base Fairfield, California Julia Crim, MD Diagnostic Imaging: Emergency Chief of Musculoskeletal Radiology Professor of Radiology University of Missouri at Columbia Columbia, Missouri Adam C Zoga, MD Director of Musculoskeletal MRI Vice-Chair for Clinical Practice Associate Professor of Radiology Thomas Jefferson University Hospital Philadelphia, Pennsylvania Michael J Tuite, MD Vice-Chair of Operations Professor of Musculoskeletal Radiology University of Wisconsin Medical School Madison, Wisconsin Terrance T Healey, MD Director, Thoracic Radiology Assistant Professor of Diagnostic Imaging Department of Diagnostic Imaging Warren Alpert Medical School of Brown University Providence, Rhode Island Carol L Andrews, MD Associate Professor Division Chief, Musculoskeletal Radiology University of Pittsburgh Medical Center Pittsburgh, Pennsylvania Gregory L Katzman, MD, MBA Associate Professor of Neuroradiology Vice-Chair of Clinical Operations Chief Quality Officer Chief Business Development Officer Department of Radiology University of Chicago Chicago, Illinois Bronwyn E Hamilton, MD Associate Professor of Radiology Neuroradiology Fellowship Co-Director Neuroradiology Division Oregon Health & Science University Portland, Oregon Michael P Federle, MD, FACR Professor and Associate Chair for Education Department of Radiology Stanford University School of Medicine Stanford, California Lane F Donnelly, MD Chief Medical Officer and Physician-in-Chief Nemours Children's Hospital Vice President and Nemours Chair of Radiology Nemours Foundation Jacksonville, Florida Professor of Radiology University of Central Florida College of Medicine Orlando, Florida Professor of Radiology Diagnostic Imaging: Emergency Florida State University College of Medicine Tallahassee, Florida Carl Merrow, MD Staff Radiologist Cincinnati Children's Hospital Medical Center Assistant Professor of Clinical Radiology University of Cincinnati College of Medicine Cincinnati, Ohio Jonathan Hero Chung, MD Associate Professor of Radiology Director of Cardiopulmonary Imaging Fellowship Director of Radiology Professional Quality Assurance National Jewish Health Denver, Colorado Karen L Salzman, MD Professor of Radiology Leslie W Davis Endowed Chair in Neuroradiology University of Utah School of Medicine Salt Lake City, Utah Michelle A Michel, MD Professor of Radiology and Otolaryngology Chief, Head and Neck Neuroradiology Medical College of Wisconsin Milwaukee, Wisconsin Christopher G Anton, MD Division Chief of Radiology Assistant Professor of Radiology and Pediatrics Cincinnati Children's Hospital Medical Center Associate Program Director University of Cincinnati Radiology Residency Cincinnati, Ohio Cheryl Petersilge, MD Clinical Professor of Radiology Cleveland Clinic Lerner College of Medicine Case Western Reserve University Cleveland, Ohio Lubdha M Shah, MD Associate Professor of Radiology Division of Neuroradiology University of Utah School of Medicine Salt Lake City, Utah Perry P Ng, MBBS (Hons), FRANZCR Assistant Professor, Department of Radiology Interventional Neuroradiologist University of Utah School of Medicine Salt Lake City, Utah Paula J Woodward, MD David G Bragg, MD and Marcia R Bragg Presidential Endowed Chair in Oncologic Imaging Professor of Radiology University of Utah School of Medicine Salt Lake City, Utah Tomás Franquet, MD, PhD Director of Thoracic Imaging Hospital de Sant Pau Diagnostic Imaging: Emergency Associate Professor of Radiology Universidad Autónoma de Barcelona Barcelona, Spain H Christian Davidson, MD Associate Professor of Radiology University of Utah School of Medicine Salt Lake City, Utah Christine M Glastonbury, MBBS Professor of Radiology and Biomedical Imaging Otolaryngology-Head and Neck Surgery and Radiation Oncology University of California, San Francisco San Francisco, California Carol C Wu, MD Instructor of Radiology Harvard Medical School Assistant Radiologist Massachusetts General Hospital Boston, Massachusetts Gary M Nesbit, MD Professor of Radiology, Neurology, Neurological Surgery, and the Dotter Interventional Institute Oregon Health & Science University Portland, Oregon Helen T Winer-Muram, MD Professor of Clinical Radiology Indiana University School of Medicine Indianapolis, Indiana John P Lichtenberger, III, MD Chief of Cardiothoracic Imaging David Grant Medical Center Travis Air Force Base Fairfield, California Assistant Professor of Radiology Uniformed Services University of the Health Sciences Bethesda, Maryland Kristine M Mosier, DMD, PhD Associate Professor of Radiology Chief, Head and Neck Radiology Indiana University School of Medicine Department of Radiology & Imaging Sciences Indianapolis, Indiana Laurie A Loevner, MD Professor of Radiology, Otorhinolaryngology, Head and Neck Surgery, Neurosurgery Perelman School of Medicine at the University of Pennsylvania Director, Head and Neck Imaging University of Pennsylvania Health System Philadelphia, Pennsylvania Miral D Jhaveri, MD Assistant Professor Director of Neuroradiology Department of Diagnostic Radiology & Nuclear Medicine Rush University Medical Center Chicago, Illinois Santiago Martínez-Jiménez, MD 10 Diagnostic Imaging: Emergency Chronic physeal stress injury Rest and immobilization SELECTED REFERENCES Chen YT et al: Update on stress fractures in female athletes: epidemiology, treatment, and prevention Curr Rev Musculoskelet Med 6(2):173-81, 2013 Tenforde AS et al: Identifying Sex-Specific Risk Factors for Stress Fractures in Adolescent Runners Med Sci Sports Exerc Epub ahead of print, 2013 Galbraith RM et al: Medial tibial stress syndrome: conservative treatment options Curr Rev Musculoskelet Med 2(3):127-33, 2009 Medial Epicondyle Avulsion > Table of Contents > Part I - Trauma > Section - Musculoskeletal > Pediatric Fractures > Medial Epicondyle Avulsion Medial Epicondyle Avulsion Christopher G Anton, MD Key Facts Terminology Acute injury Medial epicondylar (ME) avulsion Chronic stress injury Golfer's elbow, pitcher's elbow, Little Leaguer's elbow, medial tennis elbow Degeneration of common flexor tendon secondary to overload caused by chronic valgus stress Imaging Should see medial epicondyle on AP radiograph if trochlea is identified Helps to exclude entrapped medial epicondyle, can simulate trochlear ossification center Ossification pattern on radiographs Capitellum: 1-2 years old Radial head: 3-6 years Medial epicondyle: 4-7 years old Trochlea: years Olecranon: 6-12 years Lateral epicondyle: 10-11 years Unreliable fat pad sign Children > year old, ME may become extracapsular Clinical Issues 3rd most common pediatric elbow fracture Avulsion injury: 9-14 years old Older children near skeletal maturity tend to injure tendons/ligaments similar to adults Medial epicondyle avulsion, acute injury Minimally displaced: Immobilization Displacement > mm: Surgical open reduction Point tenderness and swelling over ME with elbow flexion contracture of > 15° 736 Diagnostic Imaging: Emergency (Left) Coronal graphic shows an avulsion of the medial epicondyle ossification center (Right) Lateral radiograph shows a displaced medial epicondyle fracture fragment projecting over the joint space The radius and ulna appear dislocated posteriorly It is important to recognize this medial epicondyle fragment prior to reduction so that the fragment does not get entrapped into the elbow joint after reduction of the dislocation (Left) Anteroposterior radiograph shows avulsive fragmentation of the inferior margin of the medial epicondyle ossification center (Right) Coronal T2WI MR shows hyperintense signal within the medial epicondyle and adjacent medial condyle This teenager was hit directly over the medial epicondyle by a baseball A small elbow joint effusion was also present P.I(4):477 TERMINOLOGY Abbreviations Medial epicondyle (ME) avulsion Synonyms Medial epicondylitis (apophysitis), Little Leaguer's elbow (LLE), pitcher's elbow, golfer's elbow, medial tennis elbow Definitions Acute injury Medial epicondylar avulsion 737 Diagnostic Imaging: Emergency Chronic stress injury: Golfer's elbow, pitcher's elbow, Little Leaguer's elbow, medial tennis elbow Degeneration of common flexor tendon secondary to overload caused by chronic valgus stress IMAGING General Features Best diagnostic clue Displaced medial epicondyle ossification center in acute injury Location Medial elbow ± entrapped between olecranon & trochlea after elbow dislocation Morphology Ossification pattern on radiographs Capitellum: 1-2 years old Radial head: 3-6 years old Medial epicondyle: 4-7 years old Trochlea: years old Olecranon: 6-12 years old Lateral epicondyle: 10-11 years old Should see medial epicondyle on AP radiograph if trochlea is identified Helps to exclude entrapped medial epicondyle, can simulate trochlear ossification center Medial epicondyle apophysis fuses with medial condyle by age 18-20 years Does not contribute to longitudinal growth Radiographic Findings Radiography Acute injury: Displacement of medial epicondyle ossification center Chronic injury (LLE): Enlargement, sclerosis, fragmentation, widened physis Unreliable fat pad sign Children > years old, medial epicondyle may become extracapsular May be positive if there are other fractures ± in elbow dislocation, depends on if capsule is disrupted MR Findings Medial tension overload Increased T2WI signal intensity within common flexor tendon origin at medial epicondyle Thickened tendon Hyperintense water signal intensity within tendon in case of partial tear or complete tears FS T2WI FSE or STIR images demonstrate increased signal to best advantage Hyperintense signal within common flexor muscle belly in case of muscle strain Avulsion of medial epicondyle in skeletally immature individuals Strains & tears of ulnar collateral ligament Ulnar neuritis Hyperintense T2WI signal & thickening of ulnar nerve usually within cubital tunnel Lateral compression Osteochondral injuries of humeral capitellum Hyperintense signal in capitellum on T2-weighted images May see chondromalacia & underlying bone marrow edema or cysts Loose bodies may be present Hyperintense T2WI signal in medial epicondyle in Little Leaguer's elbow Often associated tendon strain Imaging Recommendations Best imaging tool AP & lateral radiographs 1st If still questionable, 10-15° oblique view for acute avulsion Avulsed fragment usually displaces inferiorly Protocol advice AP & lateral radiographs to exclude acute avulsion T1 and FS PD FSE (best); FS T2 FSE &/or STIR for ligament/tendon evaluation 738 Diagnostic Imaging: Emergency DIFFERENTIAL DIAGNOSIS Medial Collateral Ligament Injury Valgus extension, overload injury Tear: Disruption of continuous linear hypointense signal Best imaging sequence: FS PD FSE Partial tears: “T” sign Strain: Continuous linear hypointense signal Flexor or Pronator Muscle Injury/Strain Common in throwing athlete Olecranon Stress Injury Common in throwing athlete, valgus stress Marrow edema with olecranon T2WI or STIR Capitellar Osteochondritis Dissecans 12-17 years old, valgus stress Lateral elbow pain, diffuse elbow pain worsens with activity Ulnar Neuritis Hyperintense T2WI signal & thickening of ulnar nerve usually within cubital tunnel Flexor or Pronator Muscle Strain/Tear Medial elbow pain Throwing athlete Loose Bodies Acute or repetitive injury P.I(4):478 PATHOLOGY General Features Etiology Children In children injury is often to medial epicondyle itself, manifesting as stress fracture or avulsion of epicondyle Mechanism for avulsion Forceful contraction of pronator & flexor muscle groups of forearm Fall on outstretched arm with elbow flexed & hand extended Posterior/lateral elbow dislocation (50-55%) Chronic injury (LLE) Overuse syndrome found in athletes participating in throwing sports Due to repeated valgus stress causing tendon degeneration Strain → tendinosis → tear Associated abnormalities Medial epicondyle avulsion; incidence of up to 50% in elbow dislocations Ulnar nerve injury in dislocation (25-50%) Trapped medial epicondyle in elbow joint following dislocation (up to 20%) Gross Pathologic & Surgical Features Avulsed epicondyle Thickening of tendon, ± macroscopic partial tearing or through-and-through tearing in chronic injury May include tear of ulnar collateral ligament Microscopic Features Microscopic tendon degeneration with macroscopic partial or complete tear surrounded by hemorrhage and inflammation CLINICAL ISSUES Presentation Most common signs/symptoms Point tenderness and swelling over ME with elbow flexion contracture of > 15° Other signs/symptoms 739 Diagnostic Imaging: Emergency Palpable freely mobile medial epicondyle Crepitus Athlete participating in throwing sports with onset of medial elbow pain Medial epicondylar pain, increased by valgus stress to elbow Demographics Age Avulsion injury: 9-14 years old Older children near skeletal maturity tend to injure tendons/ligaments similar to adults Gender M > F (4:1) Epidemiology 3rd most common pediatric elbow fracture Avulsion: 10% of all elbow fractures Natural History & Prognosis Good prognosis If nonunion occurs, may lead to instability Treatment Medial epicondyle avulsion, acute injury Minimally displaced: Immobilization > mm Tension bands and Kirschner wire fixation in young children Screw fixation for older children Ulnar neuropathy: Indication for surgical reduction Surgery for valgus instability Chronic tension stress injury Physical therapy and steroid injection with decrease in physical activity Tendon release Tendon repair DIAGNOSTIC CHECKLIST Image Interpretation Pearls Should see medial epicondyle when trochlear ossification center is identified Displaced medial epicondyle can simulate trochlear ossification center SELECTED REFERENCES Wenzke DR: MR Imaging of the Elbow in the Injured Athlete Radiol Clin North Am 51(2):195-213, 2013 Zellner B et al: Elbow injuries in the young athlete-an orthopedic perspective Pediatr Radiol 43 Suppl 1:129-34, 2013 Klatt JB et al: The location of the medial humeral epicondyle in children: position based on common radiographic landmarks J Pediatr Orthop 32(5):477-82, 2012 Edmonds EW: How displaced are “nondisplaced” fractures of the medial humeral epicondyle in children? Results of a three-dimensional computed tomography analysis J Bone Joint Surg Am 92(17):2785-91, 2010 Osbahr DC et al: Acute, avulsion fractures of the medial epicondyle while throwing in youth baseball players: a variant of Little League elbow J Shoulder Elbow Surg 19(7):951-7, 2010 Wei AS et al: Clinical and magnetic resonance imaging findings associated with Little League elbow J Pediatr Orthop 30(7):715-9, 2010 Schwartz ML et al: Avulsion of the medial epicondyle after ulnar collateral ligament reconstruction: imaging of a rare throwing injury AJR Am J Roentgenol 190(3):595-8, 2008 Ip D et al: Medial humeral epicondylar fracture in children and adolescents J Orthop Surg (Hong Kong) 15(2):170-3, 2007 Ahmad CS et al: Valgus extension overload syndrome and stress injury of the olecranon Clin Sports Med 23(4):665-76, x, 2004 10 Kijowski R et al: Magnetic resonance imaging of the elbow Part I: normal anatomy, imaging technique, and osseous abnormalities Skeletal Radiol 33(12):685-97, 2004 11 Williams RJ 3rd et al: Medial collateral ligament tears in the throwing athlete Instr Course Lect 53:579-86, 2004 12 Cain EL Jr et al: Elbow injuries in throwing athletes: a current concepts review Am J Sports Med 31(4):621-35, 2003 13 Parr TJ et al: Overuse injuries of the olecranon in adolescents Orthopedics 26(11):1143-6, 2003 740 Diagnostic Imaging: Emergency 14 Klingele KE et al: Little league elbow: valgus overload injury in the paediatric athlete Sports Med 32(15):1005-15, 2002 15 Chen FS et al: Medial elbow problems in the overhead-throwing athlete J Am Acad Orthop Surg 9(2):99-113, 2001 P.I(4):479 Image Gallery (Left) Anteroposterior radiograph shows an ossific fragment adjacent to the medial margin of the olecranon process of the ulna This should not be mistaken for either a trochlear or an olecranon ossification center (Right) Lateral radiograph in the same child shows an entrapped medial epicondyle ossification center This fracture was treated by surgical open reduction and fixation (Left) Coronal T2WI MR shows a displaced medial epicondyle ossification center Hyperintense fluid is between the fragment and the medial condyle of the humerus This MR was obtained in a 13-year-old baseball pitcher with an acute injury (Right) Anteroposterior radiograph shows reduction and screw fixation of the medial epicondyle avulsion fracture in the same patient 741 Diagnostic Imaging: Emergency (Left) Anteroposterior radiograph shows avulsion of the tip of the medial epicondyle in a 12 year old who started pitching weeks ago, now with elbow pain and presenting for radiographs (Right) Coronal T2WI MR in the same patient shows hyperintense signal throughout the medial epicondyle ossification center The small osseous fragment could not be identified This is an example of Little Leaguer's elbow Stress Injury > Table of Contents > Part I - Trauma > Section - Musculoskeletal > Pediatric Fractures > Stress Injury Stress Injury Key Facts Terminology Fatigue fracture Abnormal stress applied to normal bone Insufficiency fracture Normal stress applied to abnormal bone Stress response/reaction Stress upon normal bone but without presence of a discrete fracture line Chronic physeal stress injury Repetitive stress to the physis, which prevents normal endochondral ossification Imaging Stress injury Periosteal new bone or sclerotic bands on radiographs Increased T2WI ± decreased T1WI signal = stress response Transverse decreased T2WI and T1WI signal = stress fracture Evaluate on orthogonal planes so as not to overestimate severity of fracture Chronic physeal stress injury Asymmetric physeal widening on radiographs Broad metaphyseal extension of physeal signal intensity on MR Top Differential Diagnoses Osteomyelitis, bacterial Osteoid osteoma Clinical Issues Prevention is paramount to treatment of stress fracture to prevent completion of the fracture Rest and immobilization may help avoid chronic malalignment as a result of chronic physeal stress injury 742 Diagnostic Imaging: Emergency (Left) Anteroposterior radiograph of the left wrist from a 12-year-old girl gymnast shows abnormal widening of the distal radial growth plate consistent with a chronic physeal stress injury, so-called gymnast wrist (Right) Axial T2WI FS MR shows a periosteal edema pattern at the anteromedial tibias bilaterally , consistent with grade medial tibial stress syndrome, the MR correlate to shin splints (Left) Coronal T2WI FS MR from a 15-year-old girl shows transverse decreased signal of the posterior proximal tibial diaphysis compatible with an incomplete stress fracture Note the periosteal reaction and surrounding edema-like signal in soft tissues (Right) Sagittal T1WI MR in the same patient shows the true extent of involvement with sparing of the anterior ˜ 2/3 of the diaphysis and decreased signal consistent with sclerotic band related to healing cancellous bone P.I(4):481 TERMINOLOGY Definitions Fatigue fracture Abnormal stress applied to normal bone Insufficiency fracture Normal stress applied to abnormal bone Osteopenia/osteoporosis, osteogenesis imperfecta, rickets/osteomalacia, hyperparathyroidism 743 Diagnostic Imaging: Emergency Stress response/reaction Stress upon normal bone, but without presence of a discrete fracture line Chronic physeal stress injury Repetitive stress to physis, which prevents normal endochondral ossification IMAGING Radiographic Findings Stress fracture Periosteal new bone Sclerotic bands Chronic physeal stress Asymmetric broad physeal widening CT Findings Hairline fractures, areas of intracortical radiolucency, subperiosteal new bone MR Findings T1WI Decreased signal within marrow with more severe stress response Transverse decreased signal in stress fracture Review orthogonal planes so severity not overestimated T2WI FS Increased signal without discrete fracture line in stress response Transverse decreased signal in stress fracture Unicortical cleft on axial images with eccentric marrow and adjacent soft tissue edema = longitudinal stress fracture Metaphyseal extension of physeal signal intensity Broad extension = ongoing insult from chronic physeal stress injury Small tongue-like extensions = prior insult T2* GRE Shows physeal widening well Medial tibial stress syndrome Grade 1: Periosteal edema at anteromedial tibia MR equivalent of shin splints Grade 2: Increased T2WI signal within medullary canal Grade 3: Increased T2WI + decreased T1WI signal within medullary canal Grade 4: Discrete fracture line Nuclear Medicine Findings Bone scan: Sensitivity ˜ 100% Intense cortical uptake SPECT/CT Increases specificity for location of injury Excellent for pars interarticularis stress fracture DIFFERENTIAL DIAGNOSIS Osteomyelitis, Pyogenic Earliest finding may only be periosteal reaction Osteoid Osteoma Typically marked periosteal new bone May also see lucent nidus on radiographs Nidus may be difficult to see on MR, leading to incorrect diagnosis of stress injury Ewing Sarcoma “Onion skin” or “sunburst” periosteal reaction sometimes with no apparent bone involvement Large soft tissue mass on cross-sectional imaging PATHOLOGY Microscopic Features Cortical or compact bone Microfracture → osteoclasts form resorption cavities adjacent to osteons → cavities coalesce → stress fracture 744 Diagnostic Imaging: Emergency Chronic physeal stress Insult to metaphyseal vascular supply by repetitive trauma with resultant disruption of normal endochondral bone formation and extension of hypertrophic chondrocytes into metaphysis CLINICAL ISSUES Presentation Most common signs/symptoms Stress fracture Pain, swelling, warmth, discoloration Palpable periosteal thickening Chronic physeal stress injury Pain Medial tibial stress syndrome Overuse or repetitive stress injury to shin area May progress to stress fracture After lower extremity cast removal, insufficiency fx may occur secondary to disuse osteopenia Young child with refusal to bear weight may have stress/insufficiency fracture Treatment Stress fracture Prevention paramount Gradual, deliberate increase in new activity Prompt activity reduction when pain occurs Chronic physeal stress injury Rest and immobilization SELECTED REFERENCES Chen YT et al: Update on stress fractures in female athletes: epidemiology, treatment, and prevention Curr Rev Musculoskelet Med 6(2):173-81, 2013 Tenforde AS et al: Identifying Sex-Specific Risk Factors for Stress Fractures in Adolescent Runners Med Sci Sports Exerc Epub ahead of print, 2013 Galbraith RM et al: Medial tibial stress syndrome: conservative treatment options Curr Rev Musculoskelet Med 2(3):127-33, 2009 Medial Epicondyle Avulsion > Table of Contents > Part I - Trauma > Section - Musculoskeletal > Pediatric Fractures > Medial Epicondyle Avulsion Medial Epicondyle Avulsion Christopher G Anton, MD Key Facts Terminology Acute injury Medial epicondylar (ME) avulsion Chronic stress injury Golfer's elbow, pitcher's elbow, Little Leaguer's elbow, medial tennis elbow Degeneration of common flexor tendon secondary to overload caused by chronic valgus stress Imaging Should see medial epicondyle on AP radiograph if trochlea is identified Helps to exclude entrapped medial epicondyle, can simulate trochlear ossification center Ossification pattern on radiographs Capitellum: 1-2 years old Radial head: 3-6 years Medial epicondyle: 4-7 years old Trochlea: years Olecranon: 6-12 years Lateral epicondyle: 10-11 years Unreliable fat pad sign Children > year old, ME may become extracapsular Clinical Issues 745 Diagnostic Imaging: Emergency 3rd most common pediatric elbow fracture Avulsion injury: 9-14 years old Older children near skeletal maturity tend to injure tendons/ligaments similar to adults Medial epicondyle avulsion, acute injury Minimally displaced: Immobilization Displacement > mm: Surgical open reduction Point tenderness and swelling over ME with elbow flexion contracture of > 15° (Left) Coronal graphic shows an avulsion of the medial epicondyle ossification center (Right) Lateral radiograph shows a displaced medial epicondyle fracture fragment projecting over the joint space The radius and ulna appear dislocated posteriorly It is important to recognize this medial epicondyle fragment prior to reduction so that the fragment does not get entrapped into the elbow joint after reduction of the dislocation (Left) Anteroposterior radiograph shows avulsive fragmentation of the inferior margin of the medial epicondyle ossification center (Right) Coronal T2WI MR shows hyperintense signal within the medial epicondyle and adjacent medial condyle This teenager was hit directly over the medial epicondyle by a baseball A small elbow joint effusion was also present P.I(4):477 TERMINOLOGY 746 Diagnostic Imaging: Emergency Abbreviations Medial epicondyle (ME) avulsion Synonyms Medial epicondylitis (apophysitis), Little Leaguer's elbow (LLE), pitcher's elbow, golfer's elbow, medial tennis elbow Definitions Acute injury Medial epicondylar avulsion Chronic stress injury: Golfer's elbow, pitcher's elbow, Little Leaguer's elbow, medial tennis elbow Degeneration of common flexor tendon secondary to overload caused by chronic valgus stress IMAGING General Features Best diagnostic clue Displaced medial epicondyle ossification center in acute injury Location Medial elbow ± entrapped between olecranon & trochlea after elbow dislocation Morphology Ossification pattern on radiographs Capitellum: 1-2 years old Radial head: 3-6 years old Medial epicondyle: 4-7 years old Trochlea: years old Olecranon: 6-12 years old Lateral epicondyle: 10-11 years old Should see medial epicondyle on AP radiograph if trochlea is identified Helps to exclude entrapped medial epicondyle, can simulate trochlear ossification center Medial epicondyle apophysis fuses with medial condyle by age 18-20 years Does not contribute to longitudinal growth Radiographic Findings Radiography Acute injury: Displacement of medial epicondyle ossification center Chronic injury (LLE): Enlargement, sclerosis, fragmentation, widened physis Unreliable fat pad sign Children > years old, medial epicondyle may become extracapsular May be positive if there are other fractures ± in elbow dislocation, depends on if capsule is disrupted MR Findings Medial tension overload Increased T2WI signal intensity within common flexor tendon origin at medial epicondyle Thickened tendon Hyperintense water signal intensity within tendon in case of partial tear or complete tears FS T2WI FSE or STIR images demonstrate increased signal to best advantage Hyperintense signal within common flexor muscle belly in case of muscle strain Avulsion of medial epicondyle in skeletally immature individuals Strains & tears of ulnar collateral ligament Ulnar neuritis Hyperintense T2WI signal & thickening of ulnar nerve usually within cubital tunnel Lateral compression Osteochondral injuries of humeral capitellum Hyperintense signal in capitellum on T2-weighted images May see chondromalacia & underlying bone marrow edema or cysts Loose bodies may be present Hyperintense T2WI signal in medial epicondyle in Little Leaguer's elbow Often associated tendon strain Imaging Recommendations 747 Diagnostic Imaging: Emergency Best imaging tool AP & lateral radiographs 1st If still questionable, 10-15° oblique view for acute avulsion Avulsed fragment usually displaces inferiorly Protocol advice AP & lateral radiographs to exclude acute avulsion T1 and FS PD FSE (best); FS T2 FSE &/or STIR for ligament/tendon evaluation DIFFERENTIAL DIAGNOSIS Medial Collateral Ligament Injury Valgus extension, overload injury Tear: Disruption of continuous linear hypointense signal Best imaging sequence: FS PD FSE Partial tears: “T” sign Strain: Continuous linear hypointense signal Flexor or Pronator Muscle Injury/Strain Common in throwing athlete Olecranon Stress Injury Common in throwing athlete, valgus stress Marrow edema with olecranon T2WI or STIR Capitellar Osteochondritis Dissecans 12-17 years old, valgus stress Lateral elbow pain, diffuse elbow pain worsens with activity Ulnar Neuritis Hyperintense T2WI signal & thickening of ulnar nerve usually within cubital tunnel Flexor or Pronator Muscle Strain/Tear Medial elbow pain Throwing athlete Loose Bodies Acute or repetitive injury P.I(4):478 PATHOLOGY General Features Etiology Children In children injury is often to medial epicondyle itself, manifesting as stress fracture or avulsion of epicondyle Mechanism for avulsion Forceful contraction of pronator & flexor muscle groups of forearm Fall on outstretched arm with elbow flexed & hand extended Posterior/lateral elbow dislocation (50-55%) Chronic injury (LLE) Overuse syndrome found in athletes participating in throwing sports Due to repeated valgus stress causing tendon degeneration Strain → tendinosis → tear Associated abnormalities Medial epicondyle avulsion; incidence of up to 50% in elbow dislocations Ulnar nerve injury in dislocation (25-50%) Trapped medial epicondyle in elbow joint following dislocation (up to 20%) Gross Pathologic & Surgical Features Avulsed epicondyle Thickening of tendon, ± macroscopic partial tearing or through-and-through tearing in chronic injury May include tear of ulnar collateral ligament Microscopic Features 748 Diagnostic Imaging: Emergency Microscopic tendon degeneration with macroscopic partial or complete tear surrounded by hemorrhage and inflammation CLINICAL ISSUES Presentation Most common signs/symptoms Point tenderness and swelling over ME with elbow flexion contracture of > 15° Other signs/symptoms Palpable freely mobile medial epicondyle Crepitus Athlete participating in throwing sports with onset of medial elbow pain Medial epicondylar pain, increased by valgus stress to elbow Demographics Age Avulsion injury: 9-14 years old Older children near skeletal maturity tend to injure tendons/ligaments similar to adults Gender M > F (4:1) Epidemiology 3rd most common pediatric elbow fracture Avulsion: 10% of all elbow fractures Natural History & Prognosis Good prognosis If nonunion occurs, may lead to instability Treatment Medial epicondyle avulsion, acute injury Minimally displaced: Immobilization > mm Tension bands and Kirschner wire fixation in young children Screw fixation for older children Ulnar neuropathy: Indication for surgical reduction Surgery for valgus instability Chronic tension stress injury Physical therapy and steroid injection with decrease in physical activity Tendon release Tendon repair DIAGNOSTIC CHECKLIST Image Interpretation Pearls Should see medial epicondyle when trochlear ossification center is identified Displaced medial epicondyle can simulate trochlear ossification center SELECTED REFERENCES Wenzke DR: MR Imaging of the Elbow in the Injured Athlete Radiol Clin North Am 51(2):195-213, 2013 Zellner B et al: Elbow injuries in the young athlete-an orthopedic perspective Pediatr Radiol 43 Suppl 1:129-34, 2013 Klatt JB et al: The location of the medial humeral epicondyle in children: position based on common radiographic landmarks J Pediatr Orthop 32(5):477-82, 2012 Edmonds EW: How displaced are “nondisplaced” fractures of the medial humeral epicondyle in children? Results of a three-dimensional computed tomography analysis J Bone Joint Surg Am 92(17):2785-91, 2010 Osbahr DC et al: Acute, avulsion fractures of the medial epicondyle while throwing in youth baseball players: a variant of Little League elbow J Shoulder Elbow Surg 19(7):951-7, 2010 Wei AS et al: Clinical and magnetic resonance imaging findings associated with Little League elbow J Pediatr Orthop 30(7):715-9, 2010 Schwartz ML et al: Avulsion of the medial epicondyle after ulnar collateral ligament reconstruction: imaging of a rare throwing injury AJR Am J Roentgenol 190(3):595-8, 2008 Ip D et al: Medial humeral epicondylar fracture in children and adolescents J Orthop Surg (Hong Kong) 15(2):170-3, 2007 749 Diagnostic Imaging: Emergency Ahmad CS et al: Valgus extension overload syndrome and stress injury of the olecranon Clin Sports Med 23(4):665-76, x, 2004 10 Kijowski R et al: Magnetic resonance imaging of the elbow Part I: normal anatomy, imaging technique, and osseous abnormalities Skeletal Radiol 33(12):685-97, 2004 11 Williams RJ 3rd et al: Medial collateral ligament tears in the throwing athlete Instr Course Lect 53:579-86, 2004 12 Cain EL Jr et al: Elbow injuries in throwing athletes: a current concepts review Am J Sports Med 31(4):621-35, 2003 13 Parr TJ et al: Overuse injuries of the olecranon in adolescents Orthopedics 26(11):1143-6, 2003 14 Klingele KE et al: Little league elbow: valgus overload injury in the paediatric athlete Sports Med 32(15):1005-15, 2002 15 Chen FS et al: Medial elbow problems in the overhead-throwing athlete J Am Acad Orthop Surg 9(2):99-113, 2001 P.I(4):479 Image Gallery (Left) Anteroposterior radiograph shows an ossific fragment adjacent to the medial margin of the olecranon process of the ulna This should not be mistaken for either a trochlear or an olecranon ossification center (Right) Lateral radiograph in the same child shows an entrapped medial epicondyle ossification center This fracture was treated by surgical open reduction and fixation (Left) Coronal T2WI MR shows a displaced medial epicondyle ossification center 750 Hyperintense fluid is between the ... the Thoracolumbar Injury Severity Score Spine (Phila Pa 19 76) 31( 11 Suppl):S6 2-9 ; discussion S104, 2006 Image Gallery 18 Diagnostic Imaging: Emergency (Left) NECT scan of a prisoner imaged for head... to cost containment for 13 Diagnostic Imaging: Emergency emergency patients is clearly early and accurate imaging to prevent unnecessary surgery, expensive diagnostic work-ups, and hospitalizations... Riser, MA Part I - Trauma Section - Central Nervous System Introduction to CNS Imaging, Trauma > Table of Contents > Part I - Trauma > Section - Central Nervous System > Introduction to CNS Imaging,