Arthroplasty, Replacement, Knee: Replacement of the knee joint.Arthroplasty, Replacement, Hip: Replacement of the hip joint.Arthroplasty: Surgical reconstruction of a joint to relieve pain or restore motion.Arthroplasty, Replacement: Partial or total replacement of a joint.Hip Prosthesis: Replacement for a hip joint.Prosthesis Failure: Malfunction of implantation shunts, valves, etc., and prosthesis loosening, migration, and breaking.Knee Prosthesis: Replacement for a knee joint.Reoperation: A repeat operation for the same condition in the same patient due to disease progression or recurrence, or as followup to failed previous surgery.Prosthesis Design: The plan and delineation of prostheses in general or a specific prosthesis.Joint Prosthesis: Prostheses used to partially or totally replace a human or animal joint. (from UMDNS, 1999)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.Hip Joint: The joint that is formed by the articulation of the head of FEMUR and the ACETABULUM of the PELVIS.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.Prosthesis-Related Infections: Infections resulting from the implantation of prosthetic devices. The infections may be acquired from intraoperative contamination (early) or hematogenously acquired from other sites (late).Cementation: The joining of objects by means of a cement (e.g., in fracture fixation, such as in hip arthroplasty for joining of the acetabular component to the femoral component). In dentistry, it is used for the process of attaching parts of a tooth or restorative material to a natural tooth or for the attaching of orthodontic bands to teeth by means of an adhesive.Knee Joint: A synovial hinge connection formed between the bones of the FEMUR; TIBIA; and PATELLA.Bone Cements: Adhesives used to fix prosthetic devices to bones and to cement bone to bone in difficult fractures. Synthetic resins are commonly used as cements. A mixture of monocalcium phosphate, monohydrate, alpha-tricalcium phosphate, and calcium carbonate with a sodium phosphate solution is also a useful bone paste.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)Arthroplasty, Replacement, Ankle: Replacement of the ANKLE JOINT.Recovery of Function: A partial or complete return to the normal or proper physiologic activity of an organ or part following disease or trauma.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.Polyethylene: A vinyl polymer made from ethylene. It can be branched or linear. Branched or low-density polyethylene is tough and pliable but not to the same degree as linear polyethylene. Linear or high-density polyethylene has a greater hardness and tensile strength. Polyethylene is used in a variety of products, including implants and prostheses.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.Femur: The longest and largest bone of the skeleton, it is situated between the hip and the knee.Acetabulum: The part of the pelvis that comprises the pelvic socket where the head of FEMUR joins to form HIP JOINT (acetabulofemoral joint).Hip Dislocation: Displacement of the femur bone from its normal position at the HIP JOINT.Shoulder Joint: The articulation between the head of the HUMERUS and the glenoid cavity of the SCAPULA.Arthroplasty, Replacement, Elbow: Replacement of the ELBOW JOINT.Joint DiseasesFemur Head: The hemispheric articular surface at the upper extremity of the thigh bone. (Stedman, 26th ed)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.Pain, Postoperative: Pain during the period after surgery.Patella: The flat, triangular bone situated at the anterior part of the KNEE.Arthroplasty, Replacement, Finger: Partial or total replacement of one or more FINGERS, or a FINGER JOINT.Surgery, Computer-Assisted: Surgical procedures conducted with the aid of computers. This is most frequently used in orthopedic and laparoscopic surgery for implant placement and instrument guidance. Image-guided surgery interactively combines prior CT scans or MRI images with real-time video.Prosthesis Fitting: The fitting and adjusting of artificial parts of the body. (From Stedman's, 26th ed)Bone Malalignment: Displacement of bones out of line in relation to joints. It may be congenital or traumatic in origin.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.Femur Head Necrosis: Aseptic or avascular necrosis of the femoral head. The major types are idiopathic (primary), as a complication of fractures or dislocations, and LEGG-CALVE-PERTHES DISEASE.Ankylosis: Fixation and immobility of a joint.Femoral Neck Fractures: Fractures of the short, constricted portion of the thigh bone between the femur head and the trochanters. It excludes intertrochanteric fractures which are HIP FRACTURES.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.Total Disc Replacement: The replacement of intervertebral discs in the spinal column with artificial devices. The procedure is done in the lumbar or cervical spine to relieve severe pain resulting from INTERVERTEBRAL DISC DEGENERATION.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.Polyethylenes: Synthetic thermoplastics that are tough, flexible, inert, and resistant to chemicals and electrical current. They are often used as biocompatible materials for prostheses and implants.Osteolysis: Dissolution of bone that particularly involves the removal or loss of calcium.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.Surgical Procedures, Minimally Invasive: Procedures that avoid use of open, invasive surgery in favor of closed or local surgery. These generally involve use of laparoscopic devices and remote-control manipulation of instruments with indirect observation of the surgical field through an endoscope or similar device.Blood Loss, Surgical: Loss of blood during a surgical procedure.Arthrodesis: The surgical fixation of a joint by a procedure designed to accomplish fusion of the joint surfaces by promoting the proliferation of bone cells. (Dorland, 28th ed)Osteotomy: The surgical cutting of a bone. (Dorland, 28th ed)Osseointegration: The growth action of bone tissue as it assimilates surgically implanted devices or prostheses to be used as either replacement parts (e.g., hip) or as anchors (e.g., endosseous dental implants).Operative Blood Salvage: Recovery of blood lost from surgical procedures for reuse by the same patient in AUTOLOGOUS BLOOD TRANSFUSIONS. It is collected during (intraoperatively) or after completion of (postoperatively) the surgical procedures.Bone Transplantation: The grafting of bone from a donor site to a recipient site.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.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.Periprosthetic Fractures: Fractures around joint replacement prosthetics or implants. They can occur intraoperatively or postoperatively.Hip Injuries: General or unspecified injuries involving the hip.Femoral Nerve: A nerve originating in the lumbar spinal cord (usually L2 to L4) and traveling through the lumbar plexus to provide motor innervation to extensors of the thigh and sensory innervation to parts of the thigh, lower leg, and foot, and to the hip and knee joints.Hip Dislocation, Congenital: Congenital dislocation of the hip generally includes subluxation of the femoral head, acetabular dysplasia, and complete dislocation of the femoral head from the true acetabulum. This condition occurs in approximately 1 in 1000 live births and is more common in females than in males.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Surgical Wound Infection: Infection occurring at the site of a surgical incision.Leg Length Inequality: A condition in which one of a pair of legs fails to grow as long as the other, which could result from injury or surgery.Postoperative Care: The period of care beginning when the patient is removed from surgery and aimed at meeting the patient's psychological and physical needs directly after surgery. (From Dictionary of Health Services Management, 2d ed)Blood Transfusion, Autologous: Reinfusion of blood or blood products derived from the patient's own circulation. (Dorland, 27th ed)Elbow Joint: A hinge joint connecting the FOREARM to the ARM.Joint Deformities, Acquired: Deformities acquired after birth as the result of injury or disease. The joint deformity is often associated with rheumatoid arthritis and leprosy.Equipment Failure Analysis: The evaluation of incidents involving the loss of function of a device. These evaluations are used for a variety of purposes such as to determine the failure rates, the causes of failures, costs of failures, and the reliability and maintainability of devices.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.ArthritisChromium Alloys: Specific alloys not less than 85% chromium and nickel or cobalt, with traces of either nickel or cobalt, molybdenum, and other substances. They are used in partial dentures, orthopedic implants, etc.Debridement: The removal of foreign material and devitalized or contaminated tissue from or adjacent to a traumatic or infected lesion until surrounding healthy tissue is exposed. (Dorland, 27th ed)Ossification, Heterotopic: The development of bony substance in normally soft structures.Hemiarthroplasty: A partial joint replacement in which only one surface of the joint is replaced with a PROSTHESIS.Postoperative Period: The period following a surgical operation.Orthopedics: A surgical specialty which utilizes medical, surgical, and physical methods to treat and correct deformities, diseases, and injuries to the skeletal system, its articulations, and associated structures.Hip: The projecting part on each side of the body, formed by the side of the pelvis and the top portion of the femur.Metals: Electropositive chemical elements characterized by ductility, malleability, luster, and conductance of heat and electricity. They can replace the hydrogen of an acid and form bases with hydroxyl radicals. (Grant & Hackh's Chemical Dictionary, 5th ed)Patient Satisfaction: The degree to which the individual regards the health care service or product or the manner in which it is delivered by the provider as useful, effective, or beneficial.Aluminum Oxide: An oxide of aluminum, occurring in nature as various minerals such as bauxite, corundum, etc. It is used as an adsorbent, desiccating agent, and catalyst, and in the manufacture of dental cements and refractories.Femoral Fractures: Fractures of the femur.Motion Therapy, Continuous Passive: Movement of a body part initiated and maintained by a mechanical or electrical device to restore normal range of motion to joints, muscles, or tendons after surgery, prosthesis implantation, contracture flexion, or long immobilization.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.Chromium: A trace element that plays a role in glucose metabolism. It has the atomic symbol Cr, atomic number 24, and atomic weight 52. According to the Fourth Annual Report on Carcinogens (NTP85-002,1985), chromium and some of its compounds have been listed as known carcinogens.Photogrammetry: Making measurements by the use of stereoscopic photographs.Coated Materials, Biocompatible: Biocompatible materials usually used in dental and bone implants that enhance biologic fixation, thereby increasing the bond strength between the coated material and bone, and minimize possible biological effects that may result from the implant itself.Hallux Rigidus: A condition caused by degenerative arthritis (see OSTEOARTHRITIS) of the METATARSOPHALANGEAL JOINT of the great toe and characterized by pain and limited dorsiflexion, but relatively unrestricted plantar flexion.Osteonecrosis: Death of a bone or part of a bone, either atraumatic or posttraumatic.Rotator Cuff: The musculotendinous sheath formed by the supraspinatus, infraspinatus, subscapularis, and teres minor muscles. These help stabilize the head of the HUMERUS in the glenoid fossa and allow for rotation of the SHOULDER JOINT about its longitudinal axis.Humeral Head: The portion of the upper rounded extremity fitting into the glenoid cavity of the SCAPULA. (from Stedman, 27th ed)Tranexamic Acid: Antifibrinolytic hemostatic used in severe hemorrhage.Scapula: Also called the shoulder blade, it is a flat triangular bone, a pair of which form the back part of the shoulder girdle.Preoperative Period: The period before a surgical operation.Postoperative Hemorrhage: Hemorrhage following any surgical procedure. It may be immediate or delayed and is not restricted to the surgical wound.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.Early Ambulation: Procedure to accelerate the ability of a patient to walk or move about by reducing the time to AMBULATION. It is characterized by a shorter period of hospitalization or recumbency than is normally practiced.Ceramics: Products made by baking or firing nonmetallic minerals (clay and similar materials). In making dental restorations or parts of restorations the material is fused porcelain. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed & Boucher's Clinical Dental Terminology, 4th ed)Awards and PrizesArthralgia: Pain in the joint.Device Removal: Removal of an implanted therapeutic or prosthetic device.Registries: The systems and processes involved in the establishment, support, management, and operation of registers, e.g., disease registers.Rotation: Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Preoperative Care: Care given during the period prior to undergoing surgery when psychological and physical preparations are made according to the special needs of the individual patient. This period spans the time between admission to the hospital to the time the surgery begins. (From Dictionary of Health Services Management, 2d ed)Metatarsophalangeal Joint: The articulation between a metatarsal bone (METATARSAL BONES) and a phalanx.Hospitals, Low-Volume: Hospitals with a much lower than average utilization by physicians and smaller number of procedures.Ankle Joint: The joint that is formed by the inferior articular and malleolar articular surfaces of the TIBIA; the malleolar articular surface of the FIBULA; and the medial malleolar, lateral malleolar, and superior surfaces of the TALUS.Length of Stay: The period of confinement of a patient to a hospital or other health facility.Tantalum: Tantalum. A rare metallic element, atomic number 73, atomic weight 180.948, symbol Ta. It is a noncorrosive and malleable metal that has been used for plates or disks to replace cranial defects, for wire sutures, and for making prosthetic devices. (Dorland, 28th ed)Nerve Block: Interruption of NEURAL CONDUCTION in peripheral nerves or nerve trunks by the injection of a local anesthetic agent (e.g., LIDOCAINE; PHENOL; BOTULINUM TOXINS) to manage or treat pain.Cadaver: A dead body, usually a human body.Humerus: Bone in humans and primates extending from the SHOULDER JOINT to the ELBOW JOINT.Cobalt: A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis.Outcome Assessment (Health Care): Research aimed at assessing the quality and effectiveness of health care as measured by the attainment of a specified end result or outcome. Measures include parameters such as improved health, lowered morbidity or mortality, and improvement of abnormal states (such as elevated blood pressure).Titanium: A dark-gray, metallic element of widespread distribution but occurring in small amounts; atomic number, 22; atomic weight, 47.90; symbol, Ti; specific gravity, 4.5; used for fixation of fractures. (Dorland, 28th ed)Prostheses and Implants: Artificial substitutes for body parts, and materials inserted into tissue for functional, cosmetic, or therapeutic purposes. Prostheses can be functional, as in the case of artificial arms and legs, or cosmetic, as in the case of an artificial eye. Implants, all surgically inserted or grafted into the body, tend to be used therapeutically. IMPLANTS, EXPERIMENTAL is available for those used experimentally.Tuberculosis, Osteoarticular: Tuberculosis of the bones or joints.Blood Transfusion: The introduction of whole blood or blood component directly into the blood stream. (Dorland, 27th ed)Intraoperative Care: Patient care procedures performed during the operation that are ancillary to the actual surgery. It includes monitoring, fluid therapy, medication, transfusion, anesthesia, radiography, and laboratory tests.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.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Durapatite: The mineral component of bones and teeth; it has been used therapeutically as a prosthetic aid and in the prevention and treatment of osteoporosis.Disability Evaluation: Determination of the degree of a physical, mental, or emotional handicap. The diagnosis is applied to legal qualification for benefits and income under disability insurance and to eligibility for Social Security and workmen's compensation benefits.Injections, Intra-Articular: Methods of delivering drugs into a joint space.DislocationsLumbosacral Plexus: The lumbar and sacral plexuses taken together. The fibers of the lumbosacral plexus originate in the lumbar and upper sacral spinal cord (L1 to S3) and innervate the lower extremities.Venous Thrombosis: The formation or presence of a blood clot (THROMBUS) within a vein.Cervical Vertebrae: The first seven VERTEBRAE of the SPINAL COLUMN, which correspond to the VERTEBRAE of the NECK.Joint Capsule: The sac enclosing a joint. It is composed of an outer fibrous articular capsule and an inner SYNOVIAL MEMBRANE.Intraoperative Complications: Complications that affect patients during surgery. They may or may not be associated with the disease for which the surgery is done, or within the same surgical procedure.Glenoid Cavity: A depression in the lateral angle of the scapula that articulates with the head of the HUMERUS.Antibiotic Prophylaxis: Use of antibiotics before, during, or after a diagnostic, therapeutic, or surgical procedure to prevent infectious complications.Intervertebral Disc Degeneration: Degenerative changes in the INTERVERTEBRAL DISC due to aging or structural damage, especially to the vertebral end-plates.Pain: An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.Hospitals, High-Volume: Hospitals with a much higher than average utilization by physicians and a large number of procedures.Arthritis, Infectious: Arthritis caused by BACTERIA; RICKETTSIA; MYCOPLASMA; VIRUSES; FUNGI; or PARASITES.Intraoperative Period: The period during a surgical operation.Prosthesis Implantation: Surgical insertion of a prosthesis.Arthrometry, Articular: Measurements of joint flexibility (RANGE OF MOTION, ARTICULAR), usually by employing an angle-measuring device (arthrometer). Arthrometry is used to measure ligamentous laxity and stability. It is often used to evaluate the outcome of ANTERIOR CRUCIATE LIGAMENT replacement surgery.Fracture Fixation, Internal: The use of internal devices (metal plates, nails, rods, etc.) to hold the position of a fracture in proper alignment.Anesthesia, Conduction: Injection of an anesthetic into the nerves to inhibit nerve transmission in a specific part of the body.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.Activities of Daily Living: The performance of the basic activities of self care, such as dressing, ambulation, or eating.Shoulder Fractures: Fractures of the proximal humerus, including the head, anatomic and surgical necks, and tuberosities.Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)Hemarthrosis: Bleeding into the joints. It may arise from trauma or spontaneously in patients with hemophilia.Hemostasis, Surgical: Control of bleeding during or after surgery.Hip Fractures: Fractures of the FEMUR HEAD; the FEMUR NECK; (FEMORAL NECK FRACTURES); the trochanters; or the inter- or subtrochanteric region. Excludes fractures of the acetabulum and fractures of the femoral shaft below the subtrochanteric region (FEMORAL FRACTURES).Orthopedic Procedures: Procedures used to treat and correct deformities, diseases, and injuries to the MUSCULOSKELETAL SYSTEM, its articulations, and associated structures.Therapeutic Irrigation: The washing of a body cavity or surface by flowing water or solution for therapy or diagnosis.Diskectomy: Excision, in part or whole, of an INTERVERTEBRAL DISC. The most common indication is disk displacement or herniation. In addition to standard surgical removal, it can be performed by percutaneous diskectomy (DISKECTOMY, PERCUTANEOUS) or by laparoscopic diskectomy, the former being the more common.Antifibrinolytic Agents: Agents that prevent fibrinolysis or lysis of a blood clot or thrombus. Several endogenous antiplasmins are known. The drugs are used to control massive hemorrhage and in other coagulation disorders.Intervertebral Disc: Any of the 23 plates of fibrocartilage found between the bodies of adjacent VERTEBRAE.Pelvic Bones: Bones that constitute each half of the pelvic girdle in VERTEBRATES, formed by fusion of the ILIUM; ISCHIUM; and PUBIC BONE.Patient Positioning: Moving a patient into a specific position or POSTURE to facilitate examination, surgery, or for therapeutic purposes.Metal-on-Metal Joint Prostheses: Types of prosthetic joints in which both wear surfaces of the joint coupling are metallic.Foreign-Body Migration: Migration of a foreign body from its original location to some other location in the body.Replantation: Restoration of an organ or other structure to its original site.Analgesia: Methods of PAIN relief that may be used with or in place of ANALGESICS.Anesthetics, Local: Drugs that block nerve conduction when applied locally to nerve tissue in appropriate concentrations. They act on any part of the nervous system and on every type of nerve fiber. In contact with a nerve trunk, these anesthetics can cause both sensory and motor paralysis in the innervated area. Their action is completely reversible. (From Gilman AG, et. al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed) Nearly all local anesthetics act by reducing the tendency of voltage-dependent sodium channels to activate.Foreign-Body Reaction: Chronic inflammation and granuloma formation around irritating foreign bodies.Femur Neck: The constricted portion of the thigh bone between the femur head and the trochanters.Muscle Strength: The amount of force generated by MUSCLE CONTRACTION. Muscle strength can be measured during isometric, isotonic, or isokinetic contraction, either manually or using a device such as a MUSCLE STRENGTH DYNAMOMETER.Carpometacarpal Joints: The articulations between the CARPAL BONES and the METACARPAL BONES.Chi-Square Distribution: A distribution in which a variable is distributed like the sum of the squares of any given independent random variable, each of which has a normal distribution with mean of zero and variance of one. The chi-square test is a statistical test based on comparison of a test statistic to a chi-square distribution. The oldest of these tests are used to detect whether two or more population distributions differ from one another.Anesthesia, Spinal: Procedure in which an anesthetic is injected directly into the spinal cord.Treatment Failure: A measure of the quality of health care by assessment of unsuccessful results of management and procedures used in combating disease, in individual cases or series.Pulmonary Embolism: Blocking of the PULMONARY ARTERY or one of its branches by an EMBOLUS.Bone Nails: Rods of bone, metal, or other material used for fixation of the fragments or ends of fractured bones.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Bone Wires: Steel wires, often threaded through the skin, soft tissues, and bone, used to fix broken bones. Kirschner wires or apparatus also includes the application of traction to the healing bones through the wires.Medicare Part A: The compulsory portion of Medicare that is known as the Hospital Insurance Program. All persons 65 years and older who are entitled to benefits under the Old Age, Survivors, Disability and Health Insurance Program or railroad retirement, persons under the age of 65 who have been eligible for disability for more than two years, and insured workers (and their dependents) requiring renal dialysis or kidney transplantation are automatically enrolled in Medicare Part A.Amides: Organic compounds containing the -CO-NH2 radical. Amides are derived from acids by replacement of -OH by -NH2 or from ammonia by the replacement of H by an acyl group. (From Grant & Hackh's Chemical Dictionary, 5th ed)Patient Selection: Criteria and standards used for the determination of the appropriateness of the inclusion of patients with specific conditions in proposed treatment plans and the criteria used for the inclusion of subjects in various clinical trials and other research protocols.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Walking: An activity in which the body advances at a slow to moderate pace by moving the feet in a coordinated fashion. This includes recreational walking, walking for fitness, and competitive race-walking.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.Wrist Joint: The joint that is formed by the distal end of the RADIUS, the articular disc of the distal radioulnar joint, and the proximal row of CARPAL BONES; (SCAPHOID BONE; LUNATE BONE; triquetral bone).Perioperative Period: The time periods immediately before, during and following a surgical operation.Surgical Procedures, Elective: Surgery which could be postponed or not done at all without danger to the patient. Elective surgery includes procedures to correct non-life-threatening medical problems as well as to alleviate conditions causing psychological stress or other potential risk to patients, e.g., cosmetic or contraceptive surgery.Arthrography: Roentgenography of a joint, usually after injection of either positive or negative contrast medium.Polymethyl Methacrylate: Polymerized methyl methacrylate monomers which are used as sheets, moulding, extrusion powders, surface coating resins, emulsion polymers, fibers, inks, and films (From International Labor Organization, 1983). This material is also used in tooth implants, bone cements, and hard corneal contact lenses.Gait: Manner or style of walking.Patellofemoral Joint: The articulation between the articular surface of the PATELLA and the patellar surface of the FEMUR.Stress, Mechanical: A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.Slipped Capital Femoral Epiphyses: A developmental deformity in which the metaphysis of the FEMUR moves proximally and anteriorly away from FEMUR HEAD (epiphysis) at the upper GROWTH PLATE. It is most common in male adolescents and is associated with a greater risk of early OSTEOARTHRITIS of the hip.Fractures, Ununited: A fracture in which union fails to occur, the ends of the bone becoming rounded and eburnated, and a false joint occurs. (Stedman, 25th ed)Thromboembolism: Obstruction of a blood vessel (embolism) by a blood clot (THROMBUS) in the blood stream.Radiostereometric Analysis: Methods for performing three-dimensional measurement and motion analysis using stereoscopic radiographs.Vitallium: An alloy of 60% cobalt, 20% chromium, 5% molybdenum, and traces of other substances. It is used in dentures, certain surgical appliances, prostheses, implants, and instruments.Quality of Life: A generic concept reflecting concern with the modification and enhancement of life attributes, e.g., physical, political, moral and social environment; the overall condition of a human life.Hallux Valgus: Lateral displacement of the great toe (HALLUX), producing deformity of the first METATARSOPHALANGEAL JOINT with callous, bursa, or bunion formation over the bony prominence.Venous Thromboembolism: Obstruction of a vein or VEINS (embolism) by a blood clot (THROMBUS) in the blood stream.Ketorolac: A pyrrolizine carboxylic acid derivative structurally related to INDOMETHACIN. It is an NSAID and is used principally for its analgesic activity. (From Martindale The Extra Pharmacopoeia, 31st ed)Analgesia, Patient-Controlled: Relief of PAIN, without loss of CONSCIOUSNESS, through ANALGESIC AGENTS administered by the patients. It has been used successfully to control POSTOPERATIVE PAIN, during OBSTETRIC LABOR, after BURNS, and in TERMINAL CARE. The choice of agent, dose, and lockout interval greatly influence effectiveness. The potential for overdose can be minimized by combining small bolus doses with a mandatory interval between successive doses (lockout interval).Operating Rooms: Facilities equipped for performing surgery.Embolism, Fat: Blocking of a blood vessel by fat deposits in the circulation. It is often seen after fractures of large bones or after administration of CORTICOSTEROIDS.Femoracetabular Impingement: A pathological mechanical process that can lead to hip failure. It is caused by abnormalities of the ACETABULUM and/or FEMUR combined with rigorous hip motion, leading to repetitive collisions that damage the soft tissue structures.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Second-Look Surgery: A followup operation to examine the outcome of the previous surgery and other treatments, such as chemotherapy or radiation therapy.Fractures, Malunited: Union of the fragments of a fractured bone in a faulty or abnormal position. If two bones parallel to one another unite by osseous tissue, the result is a crossunion. (From Manual of Orthopaedic Terminology, 4th ed)