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)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.Knee Joint: A synovial hinge connection formed between the bones of the FEMUR; TIBIA; and PATELLA.Osteoarthritis, Hip: Noninflammatory degenerative disease of the hip joint which usually appears in late middle or old age. It is characterized by growth or maturational disturbances in the femoral neck and head, as well as acetabular dysplasia. A dominant symptom is pain on weight-bearing or motion.Knee: A region of the lower extremity immediately surrounding and including the KNEE JOINT.Arthroplasty, Replacement, Knee: Replacement of the knee joint.Knee Injuries: Injuries to the knee or the knee joint.Knee Prosthesis: Replacement for a knee joint.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.Menisci, Tibial: The interarticular fibrocartilages of the superior surface of the tibia.Arthralgia: Pain in the joint.Osteoarthritis, Spine: A degenerative joint disease involving the SPINE. It is characterized by progressive deterioration of the spinal articular cartilage (CARTILAGE, ARTICULAR), usually with hardening of the subchondral bone and outgrowth of bone spurs (OSTEOPHYTE).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.Pain Measurement: Scales, questionnaires, tests, and other methods used to assess pain severity and duration in patients or experimental animals to aid in diagnosis, therapy, and physiological studies.Pain: An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.Osteophyte: Bony outgrowth usually found around joints and often seen in conditions such as ARTHRITIS.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.Hand Joints: The articulations extending from the WRIST distally to the FINGERS. These include the WRIST JOINT; CARPAL JOINTS; METACARPOPHALANGEAL JOINT; and FINGER JOINT.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.Patella: The flat, triangular bone situated at the anterior part of the KNEE.Synovial Fluid: The clear, viscous fluid secreted by the SYNOVIAL MEMBRANE. It contains mucin, albumin, fat, and mineral salts and serves to lubricate joints.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.Injections, Intra-Articular: Methods of delivering drugs into a joint space.Chondrocytes: Polymorphic cells that form cartilage.Synovial Membrane: The inner membrane of a joint capsule surrounding a freely movable joint. It is loosely attached to the external fibrous capsule and secretes SYNOVIAL FLUID.Bone Malalignment: Displacement of bones out of line in relation to joints. It may be congenital or traumatic in origin.Finger Joint: The articulation between the head of one phalanx and the base of the one distal to it, in each finger.Hip Joint: The joint that is formed by the articulation of the head of FEMUR and the ACETABULUM of the PELVIS.Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.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.Arthroscopy: Endoscopic examination, therapy and surgery of the joint.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.Stifle: In horses, cattle, and other quadrupeds, the joint between the femur and the tibia, corresponding to the human knee.Gait: Manner or style of walking.Arthritis, Rheumatoid: A chronic systemic disease, primarily of the joints, marked by inflammatory changes in the synovial membranes and articular structures, widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, and by atrophy and rarefaction of bony structures. Etiology is unknown, but autoimmune mechanisms have been implicated.Arthrography: Roentgenography of a joint, usually after injection of either positive or negative contrast medium.Synovitis: Inflammation of a synovial membrane. It is usually painful, particularly on motion, and is characterized by a fluctuating swelling due to effusion within a synovial sac. (Dorland, 27th ed)Viscosupplementation: A therapeutic treatment typically involving INTRA-ARTICULAR INJECTIONS of HYALURONIC ACID and related compounds. The procedure is commonly used in the treatment of OSTEOARTHRITIS with the therapeutic goal to restore the viscoelasticity of SYNOVIAL FLUID, decrease pain, improve mobility and restore the natural protective functions of hyaluronan in the joint.Hyaluronic Acid: A natural high-viscosity mucopolysaccharide with alternating beta (1-3) glucuronide and beta (1-4) glucosaminidic bonds. It is found in the UMBILICAL CORD, in VITREOUS BODY and in SYNOVIAL FLUID. A high urinary level is found in PROGERIA.Knee Dislocation: Slippage of the FEMUR off the TIBIA.Arthroplasty, Replacement, Hip: Replacement of the hip joint.Quadriceps Muscle: The quadriceps femoris. A collective name of the four-headed skeletal muscle of the thigh, comprised of the rectus femoris, vastus intermedius, vastus lateralis, and vastus medialis.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.Viscosupplements: Viscoelastic solutions that are injected into JOINTS in order to alleviate symptoms of joint-related disorders such as OSTEOARTHRITIS.Joint DiseasesEditorial Policies: The guidelines and policy statements set forth by the editor(s) or editorial board of a publication.Nonprescription Drugs: Medicines that can be sold legally without a DRUG PRESCRIPTION.Publishing: "The business or profession of the commercial production and issuance of literature" (Webster's 3d). It includes the publisher, publication processes, editing and editors. Production may be by conventional printing methods or by electronic publishing.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.Temporomandibular Joint Disorders: A variety of conditions affecting the anatomic and functional characteristics of the temporomandibular joint. Factors contributing to the complexity of temporomandibular diseases are its relation to dentition and mastication and the symptomatic effects in other areas which account for referred pain to the joint and the difficulties in applying traditional diagnostic procedures to temporomandibular joint pathology where tissue is rarely obtained and x-rays are often inadequate or nonspecific. Common diseases are developmental abnormalities, trauma, subluxation, luxation, arthritis, and neoplasia. (From Thoma's Oral Pathology, 6th ed, pp577-600)