Adams and Stashak's Lameness in Horses

1224 Pages·2020·84.386 MB·English

by  Gary M. Baxter

ADAMS AND 
STASHAK’S
LAMENESS IN 
HORSES
S E V E N T H E D I T I O N
ADAMS AND
STASHAK’S
LAMENESS IN
HORSES
S E V E N T H E D I T I O N
G M. B , , ,
ary axTEr VMD MS

DIplOMaTE acVS
Associate Dean for Clinical Services
Director, Veterinary Teaching Hospital
University of Georgia
Athens, GA, USA
This edition first published 2020 © 2020 by John Wiley & Sons, Inc.
Sixth Edition © 2011 John Wiley & Sons, Inc. First through Fifth editions © 1962, 1966,
1974, 1987, 2002 Lippincott Williams & Wilkins
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Library of Congress Cataloging‐in‐Publication Data
Names: Baxter, Gary M., editor.
Title: Adams and Stashak’s lameness in horses / [edited by] Gary M. Baxter.
Other titles: Lameness in horses
Description: Seventh edition. | Hoboken, NJ : Wiley-Blackwell, 2021. |
Includes bibliographical references and index.
Identifiers: LCCN 2019046203 (print) | LCCN 2019046204 (ebook) | ISBN
9781119276685 (hardback) | ISBN 9781119276692 (adobe pdf) | ISBN
9781119276708 (epub)
Subjects: MESH: Horse Diseases | Lameness, Animal | Horses–injuries
Classification: LCC SF959.L25 (print) | LCC SF959.L25 (ebook) | NLM SF
959.L25 | DDC 636.1/089758–dc23
LC record available at https://lccn.loc.gov/2019046203
LC ebook record available at https://lccn.loc.gov/2019046204
Cover Design: Wiley
Cover Image: © Courtesy of Gary M. Baxter
Set in 10/10.5pt Sabon by SPi Global, Pondicherry, India
10 9 8 7 6 5 4 3 2 1
To my family for their understanding and encouragement
and
To all of the faculty, residents, interns, students, staff, and referring veterinarians that
I have worked with through the years at both Colorado State University
and the University of Georgia
TABLE OF CONTENTS
List of Contributors xv Forearm (Antebrachium) and Elbow 101
Preface to the Seventh Edition xix Shoulder and Scapula 102
Preface to the Sixth Edition xxi Tarsus (Hock) 105
Preface to the Fifth Edition xxiii Tibia 107
Preface to the Fourth Edition xxv Stifle 109
Acknowledgments xxvii Femur 112
Common Terminologies and Abbreviations xxix Hip 112
About the Companion Website xxxi Pelvis 113
Back 113
1 Functional Anatomy of the Equine Neck 115
Flexion Tests/Manipulation 115
Musculoskeletal System 1
Distal Limb/Phalangeal/Fetlock Flexion 115
Carpal Flexion 117
AnnA Dee FAils
Elbow Flexion 117
Anatomic Nomenclature and Usage 1
Shoulder/Upper Forelimb Flexion 117
Thoracic Limb 1
Tarsal/Hock Flexion 117
Hindlimb 34
Stifle Flexion 119
Axial Components 60
Full‐Limb Forelimb and Hindlimb Flexion 119
Acknowledgment 64
Navicular Wedge Test 119
Direct or Local Pressure plus Movement 120
2 Examination for Lameness 67
Subjective Assessment of Lameness 123
History, Visual Exam, and kevin G. keeGAn
Conformation 67 Evaluation of the Horse for Lameness at the Walk 124
Evaluation of the Horse at the Trot 126
GAry M. BAxter AnD teD s. stAshAk Evaluation of Vertical Movement of the Head for Forelimb
Introduction 67 Lameness 126
Adaptive Strategies of Lame Horses 67 Withers Movement 129
Classification of Lameness 68 Evaluation of Vertical Movement of the Pelvis for Hindlimb
Signalment and Use 71 Lameness (the Vertical Pelvic Movement [VPM]
History (Anamnesis) 71 Method) 129
Visual Examination at Rest 71 Evaluation of Pelvic Rotation for Hindlimb Lameness
Conformation 72 (The Pelvic Rotation Method [PRM]) 131
Conformation Components and Traits 74 Bilateral Lameness 132
Acknowledgment 91 Observing Movement of the Limbs 134
Palpation and Manipulation 93 Joint Angle Measurements Associated
with Lameness 134
GAry M. BAxter AnD teD s. stAshAk Stride Timing and Length Variables Associated
Foot 93 with Lameness 134
Pastern 96 Hoof Trajectory Associated with Lameness 135
Fetlock 97 Lameness Evaluation During
Metacarpus/Metatarsus (MC/MT) 97 Ipsilateral Gaits 135
Suspensory Ligament 99 Evaluation of Lameness at the Lunge 136
Flexor Tendons 100 Evaluation of Lameness Under Saddle 136
Carpus 100 Subjective Scoring Methods 137
vii
viii Table of Contents
Objective Assessment of Lameness 139 Clinical Use of CT in Equine Orthopedic Imaging 378
Contrast‐Enhanced CT 380
kevin G. keeGAn Positron Emission Tomography 383
Measurement of Ground Reaction Forces (Kinetics) 139 Conclusion 383
Measurement of Movement (Kinematics) 140
Magnetic Resonance Imaging 387
Perineural and Intrasynovial
MichAel schrAMMe AnD eMilie seGArD‐Weisse
Anesthesia 157
Introduction 387
GAry M. BAxter General Principles and Physics of MRI 387
Types of Local Anesthetics 157 Equipment, High‐ and Low‐Field Magnets,
Skin Preparation and Restraint 157 and RF Coils 387
Perineural Anesthesia 157 Sequences and Protocols for Equine MRI 389
Intrasynovial Anesthesia 167 Artifacts of MRI 390
Acknowledgment 187 Interpretation of Musculoskeletal MR Images 393
Contrast MRI Techniques 396
3 Diagnostic Imaging 189 How to Read an Equine MRI Study 397
Indications, Case Selection, Advantages,
and Disadvantages of MRI 397
Radiography 189
Magnetic Resonance Imaging of the Foot
MyrA BArrett AnD elizABeth Acutt and Pastern 397
Equipment 189 Magnetic Resonance Imaging of the Fetlock Region 409
Digital Radiography Systems 191 Magnetic Resonance Imaging of the Metacarpal
Radiation Safety 194 and Metatarsal Regions 416
Contrast Examinations 195 Magnetic Resonance Imaging of the Carpal Region 420
Principles of Radiographic Interpretation 198 Magnetic Resonance Imaging of the Tarsal Region 421
Limitations of Radiography 210 Magnetic Resonance Imaging of the Stifle Region 424
Normal Radiographic Anatomy 211
Thermography 431
Acknowledgments 299
Ultrasound 301 trAcy A. turner
Thermographic Instrumentation 431
W. rich reDDinG Principles of Use 431
Introduction 301 Specific Applications for Lameness Diagnostics 433
Ultrasound to Evaluate Tendons and Ligaments 302
Patient Preparation and Scan Protocol 303
4 Lameness of the Distal Limb 439
Ultrasonographic Assessment of Tendon/Ligament
Pathology 316
Navicular Region/Palmar Foot 439
Limitations of Ultrasonography 321
Ultrasound to Evaluate Joint Injury 323 rAnDy B. eGGleston AnD GAry M. BAxter
Indications for Ultrasonography of Joints 324
Navicular Syndrome/Disease 439
Equipment and Technique 324
Fractures of the Navicular (Distal Sesamoid) Bone 454
Ultrasonographic Appearance of Periarticular
Soft Tissue Injuries in the Foot (DDFT and Podotrochlear
Structures 326
Apparatus) 456
Ultrasonic Appearance of the Joint 327
Acknowledgments 459
Conclusions 331
Other Indications for Ultrasonography Coffin Joint and Distal Phalanx 463
of the Musculoskeletal System 332
GAry M. BAxter
New Directions in the Use of Ultrasound 335
Osteoarthritis (OA) of the Distal Interphalangeal
Nuclear Medicine/Scintigraphy 342 (DIP) Joint 463
Fractures of the Distal Phalanx (P3, Coffin Bone) 465
kurt selBerG, elizABeth Acutt, AnD AlejAnDro vAlDés‐MArtínez
Subchondral Cystic Lesions of the Distal
Principles of Nuclear Medicine 342
Phalanx (P3) 471
Radiation Safety and Protection 343
Collateral Ligament Injuries of the Distal
Imaging Equipment 343
Phalanx 472
Method for a Scintigraphic Exam of the Musculoskeletal
Ossification of the Collateral Cartilages of the Distal
System 344
Phalanx (Sidebone) 474
Indications for Nuclear Scintigraphy
of the Musculoskeletal System in Horses 347 Miscellaneous Conditions of the
Normal Bone Scan 348
Foot 477
Scintigraphic Signs of Disease 356
Abnormal Conditions for Specific Anatomical Regions 361 GAry M. BAxter
Limitations of Nuclear Medicine 373 Sole Bruises, Corns, and Subsolar Abscesses 477
Septic Pedal Osteitis 479
Computed Tomography 376
Penetrating Injuries of the Foot 481
MAthieu spriet Keratoma 483
Introduction 376 Avulsion Injuries of the Hoof 485
Equipment and Principles of CT 376 Acknowledgments 489
Table of Contents ix
Laminitis 490 5 Lameness of the Proximal Limb 597
jAMes BelknAp, AnDy pArks, AnD kAty Dern
The Carpus 597
Overview 490
Relevant Anatomy 490 chris kAWcAk
Pathogenesis: Pathophysiologic Considerations 491 Developmental Abnormalities of the Carpus 598
Pathogenesis: Structural Considerations Miscellaneous Carpal Swellings 604
of the Equine Digit 492 Dorsal Carpal Swelling 605
The Clinical Presentation: The Horse at Risk Intra‐articular Fractures 607
of Laminitis 494 Accessory Carpal Bone Fracture 612
Clinical Signs: The Acute Onset of Laminitis 496 Carpal Luxations 613
Hoof Wall Resections 509 Soft Tissue Damage to the Carpus 614
Coronary Band Grooving and Resection 509 Osteoarthritis 615
The Pastern 512 Carpometacarpal Osteoarthritis 616
Osteochondrosis of the Carpus 617
Ashlee e. WAtts AnD GAry M. BAxter Osteochondroma of the Distal Radius 617
Osteoarthritis (OA) of the PIP Joint Desmitis of the Accessory Ligament (Radial or Superior Check
(High Ringbone) 512 Ligament) of the Superficial Digital Flexor Tendon 619
Osteochondrosis (OC) of the PIP Joint 517
The Antebrachium, Elbow, and
Luxation/Subluxation of the Proximal Interphalangeal
(PIP) Joint 518 Humerus 623
Fractures of the Middle (Second) Phalanx (P2) 522
jereMy huBert
Fractures of the Proximal (First) Phalanx (P1) 525
Fractures of the Radius 623
Desmitis of the Distal Sesamoidean
The Elbow 627
Ligaments (DSLs) 532
Fractures of the Humerus 633
Desmitis of Digital Annular Ligaments 535
Neoplastic Lesions of the Humerus 637
SDFT and DDFT Abnormalities 536
Paralysis of the Radial Nerve 637
The Fetlock 541 Acknowledgment 638
MAtt Brokken AnD AliciA Bertone The Shoulder and Scapula 641
Osteochondral Fractures and Fragmentation
jereMy huBert
of the Proximal Phalanx 541
Inflammation of the Intertubercular Bursa (Bicipital
Fractures of the Proximal Sesamoid Bones 543
Bursitis) 641
Sesamoiditis 548
Inflammation of the Infraspinatus Bursa 643
Axial Osteitis/Osteomyelitis of the Proximal
Osteochondrosis (OC) of the Scapulohumeral (SH) Joint
Sesamoid Bones 549
or Shoulder 644
Osteoarthritis of the Metacarpophalangeal/
Osteoarthritis (OA) of the Scapulohumeral Joint 646
Metatarsophalangeal Joint 550
Luxation of the Scapulohumeral (Shoulder) Joint 648
Palmar/Plantar Osteochondral Disease 552
Suprascapular Nerve Injury (Sweeny) 650
Fetlock Subchondral Cystic Lesions (SCLs) 553
Fractures of the Scapula 652
Traumatic Rupture of the Suspensory
Fractures of the Supraglenoid Tubercle (Tuberosity) 653
Apparatus 554
Acknowledgment 655
Luxation of the Metacarpophalangeal/
Metatarsophalangeal Joint (Fetlock Luxation) 556 The Tarsus 657
Constriction of or by the Fetlock Palmar/Plantar
Annular Ligament 558 W. rich reDDinG
Acknowledgments 560 Introduction 657
Diagnosis of Tarsal Lameness 657
The Metacarpus and Metatarsus 563
Articular Diseases of the Tarsus 662
kylA F. ortveD AnD AliciA l. Bertone Cunean Tenectomy 672
Bucked Shin Complex and Stress Fractures Fractures and Luxations of the Tarsus 680
of the Dorsal Third Metacarpus 563 Soft Tissue Injuries of the Tarsus 687
Fractures of the Condyles of the Third Metacarpal/ Periarticular Tarsal Cellulitis 697
Metatarsal Bones (Condylar Fractures, Longitudinal Tibia and Crus 701
Articular Fractures) 567
Fractures of the Third Metacarpal/Metatarsal W. rich reDDinG
(Cannon) Bone 571 Introduction 701
Metacarpal/Metatarsal Exostosis (Splints) 572 Diagnostic Analgesia of the Crus 701
Fractures of the Small Metacarpal and  Imaging the Tibia/Crus 701
Metatarsal (Splint) Bones 576 Clinical Conditions 701
Enostosis‐Like Lesions 580 Enostosis‐Like Lesions 702
Suspensory Ligament Desmitis 580 Fractures of the Tibia 703
Superficial Digital Flexor (SDF) Tendinitis Incomplete Fractures 704
(Bowed Tendon) 585 Proximal Physeal Fractures 705
Deep Digital Flexor Tendinitis 590 Diaphyseal Fractures 706
Desmitis of the Accessory Ligament of the Deep Digital Tibial Tuberosity Fractures 706
Flexor Tendon (Distal Check Ligament) 591 Gastrocnemius Disruption in Foals and Adults 707
x Table of Contents
The Stifle: Femoropatellar Region 709 Diagnosis 779
Treatment 782
GAry M. BAxter and Ken E. Sullins Prognosis 783
Introduction 709
Femoropatellar Joint 711 Thoracolumbar Spine/Back 784
Upward Fixation of the Patella (UFP) 717 roB vAn WessuM
Desmitis of the Patellar Ligaments 719
Overriding/Impingement of Dorsal Spinous
Patellar Luxation/Subluxation 721
Processes 784
Synovial Osteochondroma in the Hindlimb 722
Supraspinous Ligament Injuries 785
The Stifle: Femorotibial Joint Region 725 Fractures of the Spinous Processes 786
Vertebral Fractures 787
chris kAWcAk Facet Joint Arthritis and Vertebral Facet Joint
Subchondral Cystic Lesions (SCLs) of the Stifle 726 Syndrome 788
Fractures 729 Discospondylitis 792
Femoral Condyle Lesions 731 Spondylosis 793
Collateral Ligament Injury 734 Scoliosis, Kyphosis, and Lordosis 794
Cruciate Ligament Disease 734
Meniscal Injuries 735 The Neck and Poll 796
Synovitis/Capsulitis/OA 737 roB vAn WessuM
Femur and Coxofemoral Region 740 Nuchal Ligament 796
Cervical Facet Joints 797
nicolAs s. ernst AnD troy n. truMBle Radiculopathy 798
The Femur 740 Discospondylitis 798
Diaphyseal and Metaphyseal Femoral Fractures 740 Cervical Fractures 798
Fractures of the Third Trochanter 744
Fibrotic and Ossifying Myopathy 744
7 Principles of Musculoskeletal
Femoral Nerve Paralysis (Crural Paralysis) 748
Calcinosis Circumscripta 749 Disease 801
Trochanteric Bursitis (Trochanteric Lameness, Whirlbone
Lameness) 750 Joint Injuries and Disease and
Ruptured Quadriceps Muscle 750
Osteoarthritis 801
The Coxofemoral Joint 750
Osteochondrosis or Osteochondritis Dissecans (OCD)/ c. WAyne McilWrAith
HIP Dysplasia of the Coxofemoral Joint 752 Anatomy and Physiology of Joints 801
Infectious Arthritis/Physitis of the Coxofemoral Pathobiology of Joints and Their Reaction to Insult
Joint 752 and Injury 808
Partial Tear/Rupture of the Ligament of the Head Primary Disease of Subchondral Bone 816
of the Femur (Round Ligament) 753
Coxofemoral Subluxation and Luxation (Dislocation Bone Injuries and Disease 820
of the Hip Joint) 754 chris kAWcAk AnD GAry M. BAxter
Osteoarthritis (OA) of the Coxofemoral Joint 757
The Immature Skeleton 820
Capital Physeal Fractures of the Femoral Head 758
Local Diseases of Bone 825
Intra‐articular Acetabular Fractures 758
Systemic Diseases of Bone 841
Acknowledgment 759
Tendon and Ligament Injuries
6 Lameness Associated with the Axial and Disease 849
Skeleton 763 lAurie r. GooDrich
Anatomy 849
The Axial Skeleton 763 Functions of Tendons and Ligaments 851
Biomechanical Properties 852
roB vAn WessuM Types of Tendon and Ligament Injuries 852
Anatomy and Biomechanics of the Vertebral Effect of Aging and Exercise on Tendon Injury 853
Column 763 Mechanisms of Tendon Degeneration 854
Primary vs. Secondary Back Pain 767 Response of Tendons and Ligaments to Injury:
The Pelvis 770 Phases of Healing 854
Monitoring Tendon Injury 856
roB vAn WessuM Biomarkers for Tendon Disease 857
Fractures of the Pelvis 770 Common Clinical Conditions of Tendons
Specific Types of Pelvic Fractures 771 and Ligaments 857
Thrombosis of the Caudal Aorta or the Iliac
Muscle Injuries and Disease 860
Arteries 775
Sacroiliac Region 777 stephAnie j. vAlBerG
Classification of Muscle Disorders 860
roB vAn WessuM Diagnosis of Specific Muscle Disorders 860
Etiology 778 Muscle Soreness 862
Clinical Signs 778 Exertional Rhabdomyolysis 865
Table of Contents xi
8 Principles of Therapy for Lameness 875 Protection and Support 917
Clinical Applications of Principles 918
Systemic/Parenteral 875 Summary 920
DreW W. koch AnD lAurie r. GooDrich Acupuncture Treatment of Limb
Parenteral NSAIDs 875 Lameness and Back Pain 921
Polysulfated Glycosaminoglycans (PSGAGs)
kevin k. hAussler
and Pentosan Polysulfate (PPS) 875
Introduction 921
Hyaluronan 876
Techniques of Stimulation 921
Bisphosphonates 877
General Indications for Treatment 922
Tetracyclines 877
Lameness 922
Estrogen 878
Chronic Back Pain 923
Methocarbamol (Robaxin) 878
Adverse Effects 924
Gabapentin 878
Manual Therapy Techniques 925
Topical/Local 881
DreW W. koch AnD lAurie r. GooDrich kevin k. hAussler
Introduction 925
Topical NSAIDs 881
Therapeutic Touch 925
Topical First Aid (Cold Therapy and Bandaging) 881
Massage Therapy 925
Dimethyl Sulfoxide 882
Passive Stretching Exercises 925
Extracorporeal Shockwave Therapy 882
Mobilization 926
Regional Perfusion 882
Joint Mobilization and Manipulation 926
Therapeutic Ultrasound, Lasers, and
Contraindications 927
Electromagnetics 883
Counterirritation 883 Rehabilitation/Physical Therapy 929
Intrasynovial 886 MelissA kinG, kAtherine ellis, AnD nArelle c. stuBBs
lAuren e. sMAnik AnD lAurie r. GooDrich Introduction 929
Corticosteroids 886 Clinical and Client Demand for Rehabilitation/PT 929
Hyaluronan 888 Manual Therapy 930
Corticosteroid and HA Combinations 889 Proprioceptive Facilitation/Neuromotor Control
IA Polysulfated Glycosaminoglycans 889 Techniques 934
Polyglycan® 890 Physical Modalities 936
Autologous Conditioned Serum 890 Conclusion 943
Platelet‐Rich Plasma 890
Autologous Protein Solution 891 9 Occupational‐Related Lameness
Bone Marrow‐ or Fat‐Derived Mesenchymal Stem Cell Conditions 949
Therapy 891
Polyacrylamide Hydrogel 891
The Thoroughbred Racehorse 949
Miscellaneous 892
Intrasynovial Therapy: Practical Considerations 892 ryAn cArpenter
Risk Factors for Injury 949
Intralesional 896
Diagnosis of Lameness 950
sArA k.t. steWArD AnD lAurie r. GooDrich Common Conditions 951
Introduction 896
The Standardbred Racehorse 964
Hyaluronan and Polysulfated Glycosaminoglycans 896
Autologous Cell Therapies: Mesenchymal Stem Cell kiMBerly johnston AnD FrAnk A. nickels
Therapy, Autologous Bone Marrow Aspirate, Tendon‐ Description of the Sport 964
Derived Progenitor Cells 896 Lameness Exam 965
Blood‐Derived Biologics: Platelet‐Rich Plasma, Specific Lameness Conditions 966
Autologous Conditioned Serum, Autologous Protein
The Racing Quarter Horse 972
Solution, and Bone Marrow Aspirate 897
Corticosteroids 898 nAncy l. GooDMAn AnD lArry r. overly
Miscellaneous 898 Introduction 972
Oral/Nutritional 900 Conformation Relating to Lameness 972
Training the Racing Quarter Horse 973
nicolAs s. ernst AnD troy n. truMBle Shoeing 973
Nonsteroidal Anti‐Inflammatory Drugs 900 Lameness Related to Track Surface 973
Nutraceuticals 903 Lameness Examination 973
Specific Lameness Conditions 975
Therapeutic Trimming and Shoeing 911
The Western Performance Horse 980
AnDreW h. pArks
Introduction 911 roBin M. DABAreiner
Examination of the Limb Introduction 980
for Therapeutic Shoeing 911 Team Roping Horses 980
The Trim 912 Tie‐Down and Breakaway Roping 981
Shoeing 912 Barrel Racing 982