Etiopathogenic Bases and Therapeutic Implications -- Background: Patellofemoral Malalignment versus Tissue Homeostasis -- Pathogenesis of Anterior Knee Pain and Patellar Instability in the Active Young -- Neuroanatomical Bases for Anterior Knee Pain in the Young Patient: “Neural Model” -- Biomechanical Bases for Anterior Knee Pain and Patellar Instability in the Young Patient -- Anatomy of Patellar Dislocation -- Evaluation of the Patient with Anterior Knee Pain and Patellar Instability -- Uncommon Causes of Anterior Knee Pain -- Risk Factors and Prevention of Anterior Knee Pain -- Conservative Treatment of Athletes with Anterior Knee Pain -- Conservative Management of Anterior Knee Pain: The McConnell Program -- Skeletal Malalignment and Anterior Knee Pain: Rationale, Diagnosis, and Management -- Treatment of Symptomatic Deep Cartilage Defects of the Patella and Trochlea with and without Patellofemoral Malalignment: Basic Science and Treatment -- Autologous Periosteum Transplantation to Treat Full-Thickness Patellar Cartilage Defects Associated with Severe Anterior Knee Pain -- Patella Plica Syndrome -- Patellar Tendinopathy: Where Does the Pain Come From? -- Patellar Tendinopathy: The Science Behind Treatment -- Prevention of Anterior Knee Pain after Anterior Cruciate Ligament Reconstruction -- Lysis of Pretibial Patellar Tendon Adhesions (Anterior Interval Release) to Treat Anterior Knee Pain after ACL Reconstruction -- Donor-Site Morbidity after Anterior Cruciate Ligament Reconstruction Using Autografts -- Clinical Cases Commented -- Complicated Case Studies -- Failure of Patellofemoral Surgery: Analysis of Clinical Cases -- Arthrofibrosis and Patella Infera -- Neuromatous Knee Pain: Evaluation and Management -- Epilogue.