Posterior Cruciate Ligament: A strong ligament of the knee that originates from the anterolateral surface of the medial condyle of the femur, passes posteriorly and inferiorly between the condyles, and attaches to the posterior intercondylar area of the tibia.Anterior Cruciate Ligament: A strong ligament of the knee that originates from the posteromedial portion of the lateral condyle of the femur, passes anteriorly and inferiorly between the condyles, and attaches to the depression in front of the intercondylar eminence of the tibia.Knee Injuries: Injuries to the knee or the knee joint.Ligaments, Articular: Fibrous cords of CONNECTIVE TISSUE that attach bones to each other and hold together the many types of joints in the body. Articular ligaments are strong, elastic, and allow movement in only specific directions, depending on the individual joint.Knee Joint: A synovial hinge connection formed between the bones of the FEMUR; TIBIA; and PATELLA.Ganglion Cysts: Nodular tumor-like lesions or mucoid flesh, arising from tendon sheaths, LIGAMENTS, or JOINT CAPSULE, especially of the hands, wrists, or feet. They are not true cysts as they lack epithelial wall. They are distinguished from SYNOVIAL CYSTS by the lack of communication with a joint cavity or the SYNOVIAL MEMBRANE.Anterior Cruciate Ligament Reconstruction: Rebuilding of the ANTERIOR CRUCIATE LIGAMENT to restore functional stability of the knee. AUTOGRAFTING or ALLOGRAFTING of tissues is often used.Ligaments: Shiny, flexible bands of fibrous tissue connecting together articular extremities of bones. They are pliant, tough, and inextensile.Arthroscopy: Endoscopic examination, therapy and surgery of the joint.Rupture: Forcible or traumatic tear or break of an organ or other soft part of the body.Joint Instability: Lack of stability of a joint or joint prosthesis. Factors involved are intra-articular disease and integrity of extra-articular structures such as joint capsule, ligaments, and muscles.Reconstructive Surgical Procedures: Procedures used to reconstruct, restore, or improve defective, damaged, or missing structures.Tendons: Fibrous bands or cords of CONNECTIVE TISSUE at the ends of SKELETAL MUSCLE FIBERS that serve to attach the MUSCLES to bones and other structures.Range of Motion, Articular: The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate MUSCLE STRETCHING EXERCISES.Tibia: The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the FIBULA laterally, the TALUS distally, and the FEMUR proximally.Knee Dislocation: Slippage of the FEMUR off the TIBIA.Menisci, Tibial: The interarticular fibrocartilages of the superior surface of the tibia.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Exostoses: Benign hypertrophy that projects outward from the surface of bone, often containing a cartilaginous component.Orthopedic Procedures: Procedures used to treat and correct deformities, diseases, and injuries to the MUSCULOSKELETAL SYSTEM, its articulations, and associated structures.Arthroplasty, Replacement, Knee: Replacement of the knee joint.Cadaver: A dead body, usually a human body.Patellar Ligament: A band of fibrous tissue that attaches the apex of the PATELLA to the lower part of the tubercle of the TIBIA. The ligament is actually the caudal continuation of the common tendon of the QUADRICEPS FEMORIS. The patella is embedded in that tendon. As such, the patellar ligament can be thought of as connecting the quadriceps femoris tendon to the tibia, and therefore it is sometimes called the patellar tendon.Soft Tissue Injuries: Injuries of tissue other than bone. The concept is usually general and does not customarily refer to internal organs or viscera. It is meaningful with reference to regions or organs where soft tissue (muscle, fat, skin) should be differentiated from bones or bone tissue, as "soft tissue injuries of the hand".Patellofemoral Joint: The articulation between the articular surface of the PATELLA and the patellar surface of the FEMUR.Femur: The longest and largest bone of the skeleton, it is situated between the hip and the knee.Periodontal Ligament: The fibrous CONNECTIVE TISSUE surrounding the TOOTH ROOT, separating it from and attaching it to the alveolar bone (ALVEOLAR PROCESS).Osteoarthritis, Knee: Noninflammatory degenerative disease of the knee joint consisting of three large categories: conditions that block normal synchronous movement, conditions that produce abnormal pathways of motion, and conditions that cause stress concentration resulting in changes to articular cartilage. (Crenshaw, Campbell's Operative Orthopaedics, 8th ed, p2019)Bone-Patellar Tendon-Bone Grafting: Fixation of the ANTERIOR CRUCIATE LIGAMENT, during surgical reconstruction, by the use of a bone-patellar tendon graft.Weight-Bearing: The physical state of supporting an applied load. This often refers to the weight-bearing bones or joints that support the body's weight, especially those in the spine, hip, knee, and foot.Knee Prosthesis: Replacement for a knee joint.Stifle: In horses, cattle, and other quadrupeds, the joint between the femur and the tibia, corresponding to the human knee.Longitudinal Ligaments: Two extensive fibrous bands running the length of the vertebral column. The anterior longitudinal ligament (ligamentum longitudinale anterius; lacertus medius) interconnects the anterior surfaces of the vertebral bodies; the posterior longitudinal ligament (ligamentum longitudinale posterius) interconnects the posterior surfaces. The commonest clinical consideration is OSSIFICATION OF POSTERIOR LONGITUDINAL LIGAMENT. (From Stedman, 25th ed)Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Athletic Injuries: Injuries incurred during participation in competitive or non-competitive sports.Recovery of Function: A partial or complete return to the normal or proper physiologic activity of an organ or part following disease or trauma.Fluoroscopy: Production of an image when x-rays strike a fluorescent screen.Tendon Transfer: Surgical procedure by which a tendon is incised at its insertion and placed at an anatomical site distant from the original insertion. The tendon remains attached at the point of origin and takes over the function of a muscle inactivated by trauma or disease.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Patella: The flat, triangular bone situated at the anterior part of the KNEE.Ossification of Posterior Longitudinal Ligament: A calcification of the posterior longitudinal ligament of the spinal column, usually at the level of the cervical spine. It is often associated with anterior ankylosing hyperostosis.Imaging, Three-Dimensional: The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.Knee: A region of the lower extremity immediately surrounding and including the KNEE JOINT.Medial Collateral Ligament, Knee: The ligament that travels from the medial epicondyle of the FEMUR to the medial margin and medial surface of the TIBIA. The medial meniscus is attached to its deep surface.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Postoperative Complications: Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.Soccer: A game in which a round inflated ball is advanced by kicking or propelling with any part of the body except the hands or arms. The object of the game is to place the ball in opposite goals.Basketball: A competitive team sport played on a rectangular court having a raised basket at each end.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Broad Ligament: A broad fold of peritoneum that extends from the side of the uterus to the wall of the pelvis.Cartilage, Articular: A protective layer of firm, flexible cartilage over the articulating ends of bones. It provides a smooth surface for joint movement, protecting the ends of long bones from wear at points of contact.Osteoarthritis: A progressive, degenerative joint disease, the most common form of arthritis, especially in older persons. The disease is thought to result not from the aging process but from biochemical changes and biomechanical stresses affecting articular cartilage. In the foreign literature it is often called osteoarthrosis deformans.