Clinical-MRI Correlations of Anterior Knee Pain : Common and Uncommon Causes

The book addresses comprehensively the normal and pathological MRI appearance of the structures of the anterior compartment of the knee, potential sources of pain, in a systematic way, on anatomical layers, from superficial to deep, respectively, from prepatellar soft tissues to intra-articular structures (the synovial lining, patellar and trochlear cartilage). Anterior knee pain can affect any age group and causes a non-specific clinical picture, making it difficult to establish a precise diagnosis and proper management. MRI is currently the standard gold investigation and findings of common an uncommon causes of anterior knee pain are presented. Written by a radiologist and an orthopaedic surgeon with longstanding experience in MRI of musculoskeletal pathology and in sports traumatology, respectively, the book also presents a unique selection of 80 clinical cases of common and less common pathological conditions of anterior knee pain and subdivided in four groups, according to age, from children and adolescents to older adults. Radiologists and orthopaedic surgeons, as well as sport medicine specialists and physiatrists, will find in this book an invaluable tool for their clinical practice. Preface Acknowledgments Contents 1: Clinical Examination of the Patient with Anterior Knee Pain 1.1 Introduction 1.2 Patient’s History 1.3 Physical Examination of the Knee 1.3.1 Inspection 1.3.1.1 Standing Examination 1.3.1.2 Seated Examination 1.3.1.3 Supine Examination 1.3.1.4 Side-Lying Examination 1.3.2 Palpation 1.4 Specific Stress Tests 1.4.1 Tests for the Medial and Lateral Collateral Ligaments (MLCL) 1.4.2 Tests for Meniscal Injuries 1.4.2.1 Joint Line Tenderness 1.4.2.2 McMurray Test 1.4.3 Tests for Patellofemoral Disorders 1.4.3.1 Patellar Tilt and Glide 1.4.3.2 Patellofemoral Grinding Test 1.4.3.3 Clarke Sign or Test 1.4.3.4 Apprehension Test for Patellar Dislocation 1.4.3.5 Patellar Instability 1.4.3.6 Wilson Sign 1.4.3.7 Q Angle 1.4.3.8 J-Sign References 2: Condition Causing Anterior Knee Pain 2.1 Patellofemoral Pain 2.1.1 Introduction Patellofemoral Pain 2.1.2 Terminology and Defining of PFP 2.1.3 Clinical Presentation 2.1.3.1 History 2.1.4 Physical Performance Measures 2.2 Patellar Instability 2.2.1 Introduction 2.2.2 Anatomic Structures and Abnormal Biomechanics of the Patellofemoral Joint Involved in Patellar Instability 2.2.3 Classification of Patellar Instability 2.2.4 Clinical Evaluation 2.2.4.1 History 2.2.4.2 Physical Examination 2.3 Patellofemoral Osteoarthritis (PFOA) 2.3.1 Introduction 2.3.2 Risk Factors Associated with Patellofemoral OA 2.3.3 Patellofemoral Pain and Patellofemoral Osteoarthritis 2.3.4 Clinical Presentation of PFOA 2.3.4.1 History 2.3.4.2 Physical Examination Palpation 2.4 Patellar Tendinopathy “Jumper’s Knee” 2.4.1 Introduction 2.4.2 History and Physical Examination 2.4.3 Differential Diagnosis 2.5 Lateral Patellar Compression Syndrome 2.5.1 Introduction 2.5.2 Anatomic and Biomechanical Abnormalities 2.5.3 Clinical Presentation 2.6 Synovial Plica Syndrome 2.6.1 Introduction 2.6.2 Pathophysiology 2.6.3 Clinical Presentation 2.6.3.1 History 2.6.3.2 Physical Examination 2.7 Sinding-Larsen-Johansson Syndrome 2.7.1 Introduction 2.7.2 Pathophysiology 2.7.3 Risk Factors 2.7.4 Clinical Presentation 2.7.5 Differential Diagnosis 2.8 Osgood–Schlatter’s Disease (OSD) 2.8.1 Introduction 2.8.2 Pathophysiology 2.8.3 Risk Factors 2.8.4 Clinical Presentation 2.8.5 Differential Diagnosis 2.9 Juvenile Osteochondritis Dissecans (JOCD) 2.9.1 Introduction 2.9.2 Etiology 2.9.3 Clinical Presentation 2.10 Hoffa Syndrome 2.10.1 Introduction 2.10.2 Anatomic and Biological Characteristics of IPFP 2.10.3 Pathophysiology 2.10.4 Physical Examination 2.10.5 Clinical Diagnosis 2.11 Superficial Patellar Bursitis 2.11.1 Introduction 2.11.2 Normal Anatomy 2.11.3 Pathophysiology 2.11.4 Clinical Presentation 2.11.4.1 History 2.11.4.2 Physical Examination 2.12 Patellar Fractures 2.12.1 Introduction 2.12.2 Anatomy and Biomechanics 2.12.3 Mechanism of Injury and Classification of Patellar Fractures 2.12.4 Clinical Presentation 2.13 Symptomatic Bipartite 2.13.1 Introduction 2.13.2 Classification 2.13.3 Pathophysiology 2.13.4 Causes of Pain 2.13.5 Clinical Presentation 2.14 Idiopathic Anterior Knee Pain 2.14.1 Introduction 2.14.2 Clinical Presentation References 3: MRI Findings of Superficial Prepatellar Soft Tissues 3.1 Introduction 3.2 Superficial Prepatellar Bursae 3.2.1 Superficial Prepatellar Bursitis 3.2.2 Superficial Infrapatellar Bursitis 3.3 Prepatellar Morel-Lavallée Lesion 3.3.1 Pathologic and Anatomic Features 3.3.2 Clinical Presentation 3.3.3 Diagnostic Imaging 3.3.4 MRI Classification of MLL 3.3.5 Differential Diagnoses 3.4 Prepatellar Subcutaneous Fat 3.4.1 Pseudo-Bursitis References 4: Quadriceps Tendon 4.1 Introduction 4.2 Normal MRI Anatomy of the Quadriceps Tendon 4.3 MRI Pathological Findings of Quadriceps Tendon Injuries 4.3.1 Complete Ruptures of the Quadriceps Tendon 4.4 Incomplete Ruptures of the Quadriceps Tendon 4.5 Quadriceps Tendinopathy 4.5.1 Summary References 5: Patella 5.1 Introduction 5.2 MRI Anatomy Normal Appearance 5.2.1 Osseous Anatomy 5.2.1.1 Patellar Facets Medial Facet Lateral Facet 5.2.1.2 Patellar Cartilage 5.2.2 Soft Tissue Anatomy 5.2.2.1 Patellar Retinaculum The Medial Retinaculum and Ligaments The Lateral Retinaculum and Iliotibial Band 5.3 MRI Patellar Measurements 5.3.1 MRI Measurements of Patellar Height in the Sagittal Plane 5.3.1.1 Patella Alta 5.3.1.2 Patella Baja 5.3.2 MRI Measurements of Patellar Position in the Axial Plane 5.3.2.1 Patellar Facet Asymmetry 5.3.2.2 Patellar Tilt and Subluxation 5.3.2.3 Lateral Displacement of the Patella 5.3.2.4 The Tibial Tubercle–trochlear Groove Distance 5.4 Acute Patellar Dislocation/Subluxation, MRI Findings 5.4.1 Introduction 5.4.2 Patellofemoral Stabilizers 5.4.2.1 Active Stabilizers 5.4.2.2 Passive Stabilizers 5.4.2.3 Static Stabilizers 5.4.3 Specific Anatomical Risk Factors for Knee Instability/Dislocation 5.4.3.1 Trochlear Dysplasia 5.4.3.2 Femoral Sulcus Angle 5.4.3.3 Lateral Trochlear Inclination 5.4.3.4 Trochlear Facet Asymmetry 5.4.3.5 Trochlear Depth 5.4.3.6 The Tibial Tubercle–Trochlear Groove (TT-TG) Distance 5.4.4 Injury Mechanism of APD 5.4.5 Clinical Examination of APD 5.4.6 MRI Findings After Acute Patellar Dislocation 5.4.6.1 Injuries to Medial Patellar Stabilizers 5.4.6.2 Bone Contusion and Osteochondral Injury Mechanism of Injury Contusions of the Medial Patella and Lateral Femoral Condyle Intra-articular Bodies 5.5 Recurrent Lateral Patellar Dislocation 5.5.1 Predisposing Factors of Recurrent Patellar Dislocation 5.5.2 MR Imaging Findings After Recurrent Patellar Dislocation 5.5.2.1 Patellar and Lateral Condylar Injury (Bone Contusion and Osteochondral Injury) Effusion Cartilage Lesions in Patellofemoral Dislocations The Medial Patellar Stabilizers Injury 5.6 Patellar Contusion and Fracture 5.6.1 Mechanism of Injury of Patellar Fractures 5.6.2 Clinical and Imagistic Evaluation 5.6.3 Types of Patellar Fractures: MRI Illustration 5.6.3.1 Sleeve Fractures 5.6.3.2 Patellar Fractures Following Acute and Chronic Patellar Dislocation 5.6.3.3 Types of Posttraumatic Patellar Fractures Patellar Vertical Fractures Patellar Transverse Fractures Patellar Stellate Fractures Comminuted Fractures 5.7 Bipartite Patella 5.7.1 Clinical Features and Classification of Bipartite 5.7.2 MR Findings Associated with an Asymptomatic Bipartite Patella 5.8 Dorsal Defect of the Patella References 6: Patellar Tendon and Tibial Tubercle 6.1 Introduction 6.2 Normal MRI Anatomy of Patellar Tendon 6.3 MRI Pathological Findings of Patellar Tendon 6.3.1 Patellar Tendinopathy 6.3.1.1 Risk Factors 6.3.1.2 Pathogenesis 6.3.1.3 MRI Features of the Patellar Tendinopathy 6.3.2 Sinding-Larsen-Johansson Syndrome and Patellar Sleeve Fractures 6.3.2.1 MRI Features of Sinding-Larsen-Johansson Syndrome and Patellar Sleeve Fractures 6.4 Patellar Tendon Rupture 6.4.1 Classification and MRI Appearance 6.5 Osgood-Schlatter Syndrome and Tibial Tubercle Avulsion Fractures 6.5.1 Pathophysiology and MRI Findings References 7: Intracapsular and Extra Synovial Peripatellar Fat Pads 7.1 Introduction 7.2 Normal MRI Anatomy and Physiology of Peripatellar Fat Pad 7.2.1 Infrapatellar Fat Pad (Hoffa’s Fat Pad—HFP) 7.2.2 Suprapatellar Fat Pad 7.3 MRI Pathological Findings of Infrapatellar Fat Pad 7.3.1 Intrinsic Pathology of Infrapatellar Fat Pad 7.3.1.1 Hoffa’s Disease 7.3.1.2 Superolateral Hoffa’s Fat Pad Edema 7.3.1.3 Intracapsular Chondroma 7.3.1.4 Localized Nodular Synovitis 7.3.1.5 Post-Arthroscopy and Post-Surgery Fibrosis 7.3.1.6 Shear Injury 7.3.2 Extrinsic Pathology of Infrapatellar Fat Pad 7.3.2.1 Intra-Articular Pathology 7.3.2.2 Hoffa’s Fat Pad Anterior Extracapsular Disorders 7.4 MRI Pathological Findings of Suprapatellar Fat Pad 7.4.1 MRI Pathological Findings of Anterior (Quadriceps) Suprapatellar Fat Pad Quadriceps Fat Pad Lesion 7.4.2 MRI Pathological Findings of Suprapatellar Posterior Prefemoral Fat Pad References 8: Intra-articular Structures, the Synovial Lining, Patellofemoral Osteoarthritis 8.1 Introduction 8.2 MRI Compartments 8.2.1 Central Compartment 8.2.2 Suprapatellar Pouch 8.2.3 Posterior Femoral Recesses 8.3 Synovial Plicae of the Knee 8.3.1 Embryology and Anatomy 8.3.2 Classification and Imaging Appearance of Synovial Plicae of the Knee Joint 8.3.2.1 Suprapatellar Plica 8.3.2.2 Medial Patellar Plica 8.3.2.3 Infrapatellar Plica 8.3.2.4 Lateral Synovial Plica 8.4 Pigmented Villonodular Synovitis 8.4.1 Clinical Characteristics 8.4.2 Diagnosis of PVNS 8.5 MRI of Synovial Chondromatosis 8.5.1 Epidemiology and Pathogenesis 8.5.2 Clinical Characteristics 8.5.3 MRI Imaging Characteristics 8.6 Patellofemoral Joint Osteoarthritis 8.6.1 Biomechanics of the PFJOA 8.6.2 Clinical Manifestation 8.6.3 MRI Assessment of Patellofemoral Joint Osteoarthritis References 9: Clinical-MRI Cases Selected by Age Group 9.1 Children and Adolescents (10–18 Years)—20 Cases 9.2 Early Adulthood (18–30 Years)—20 Cases 9.3 Adulthood (30–50 Years)—20 Cases 9.4 Older Adult Hood (>50 Years)—20 Cases