Patella: The flat, triangular bone situated at the anterior part of the KNEE.Chondromalacia Patellae: A degeneration of the ARTICULAR CARTILAGE of the PATELLA, caused by a decrease in sulfated MUCOPOLYSACCHARIDES in the ground substance. When accompanied by pain, it is sometimes considered part of or confused with PATELLOFEMORAL PAIN SYNDROME.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.Cartilage Diseases: Pathological processes involving the chondral tissue (CARTILAGE).Patellofemoral Joint: The articulation between the articular surface of the PATELLA and the patellar surface of the FEMUR.Patellar Dislocation: Displacement of the PATELLA from the femoral groove.Knee Joint: A synovial hinge connection formed between the bones of the FEMUR; TIBIA; and PATELLA.Nail-Patella Syndrome: A syndrome of multiple abnormalities characterized by the absence or hypoplasia of the PATELLA and congenital nail dystrophy. It is a genetically determined autosomal dominant trait.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.DislocationsKnee Prosthesis: Replacement for a knee joint.Arthroplasty, Replacement, Knee: Replacement of the knee joint.Prochloron: A genus of PROCHLOROPHYTES containing unicellular, spherical bacteria without a mucilaginous sheath. They are found almost exclusively as extracellular symbionts of colonial ASCIDIANS on subtropical or tropical marine shores.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)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.Femur: The longest and largest bone of the skeleton, it is situated between the hip and the knee.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.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.Patellofemoral Pain Syndrome: A syndrome characterized by retropatellar or peripatellar PAIN resulting from physical and biochemical changes in the patellofemoral joint. The pain is most prominent when ascending or descending stairs, squatting, or sitting with flexed knees. There is a lack of consensus on the etiology and treatment. The syndrome is often confused with (or accompanied by) CHONDROMALACIA PATELLAE, the latter describing a pathological condition of the CARTILAGE and not a syndrome.Arthralgia: Pain in the joint.Osteochondritis: Inflammation of a bone and its overlaying CARTILAGE.Knee Injuries: Injuries to the knee or the knee 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.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.Knee: A region of the lower extremity immediately surrounding and including the KNEE JOINT.Mollusca: A phylum of the kingdom Metazoa. Mollusca have soft, unsegmented bodies with an anterior head, a dorsal visceral mass, and a ventral foot. Most are encased in a protective calcareous shell. It includes the classes GASTROPODA; BIVALVIA; CEPHALOPODA; Aplacophora; Scaphopoda; Polyplacophora; and Monoplacophora.Joint DiseasesAnatomic Landmarks: Reference points located by visual inspection, palpation, or computer assistance, that are useful in localizing structures on or within the human body.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Lead: A soft, grayish metal with poisonous salts; atomic number 82, atomic weight 207.19, symbol Pb. (Dorland, 28th)Cadaver: A dead body, usually a human body.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.Bone Malalignment: Displacement of bones out of line in relation to joints. It may be congenital or traumatic in origin.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.Arthroscopy: Endoscopic examination, therapy and surgery of the joint.Bone Diseases, DevelopmentalElectronic Mail: Messages between computer users via COMPUTER COMMUNICATION NETWORKS. This feature duplicates most of the features of paper mail, such as forwarding, multiple copies, and attachments of images and other file types, but with a speed advantage. The term also refers to an individual message sent in this way.Food Dispensers, Automatic: Mechanical food dispensing machines.Editorial Policies: The guidelines and policy statements set forth by the editor(s) or editorial board of a publication.Authorship: The profession of writing. Also the identity of the writer as the creator of a literary production.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.Postal Service: The functions and activities carried out by the U.S. Postal Service, foreign postal services, and private postal services such as Federal Express.Internet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.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.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Achyranthes: A plant genus of the family AMARANTHACEAE, order Caryophyllales, which has been used in traditional medicine (MEDICINE, CHINESE TRADITIONAL).Smilax: A plant genus of the family SMILACACEAE. Members contain smiglasides (phenylpropanoid glycosides) and steroidal saponins. Commercially it is sometimes adulterated with HEMIDESMUS, which would affect experimental results.Word Association Tests: Lists of words to which individuals are asked to respond ascertaining the conceptual meaning held by the individual.Semantics: The relationships between symbols and their meanings.Foot: The distal extremity of the leg in vertebrates, consisting of the tarsus (ANKLE); METATARSUS; phalanges; and the soft tissues surrounding these bones.Phonetics: The science or study of speech sounds and their production, transmission, and reception, and their analysis, classification, and transcription. (Random House Unabridged Dictionary, 2d ed)Speech Perception: The process whereby an utterance is decoded into a representation in terms of linguistic units (sequences of phonetic segments which combine to form lexical and grammatical morphemes).

The clinical manifestations and pathomechanics of contracture of the extensor mechanism of the knee. (1/666)

Experience with thirty-eight Asian children and adolescents who presented with either stiffness of the knee, genu recurvatum, habitual dislocation of the patella or congenital lateral dislocation of the patella showed that all those disorders were manifestations of contracture of the extensor mechanism, which fell into two groups according to the components involved. In Group I the main components affected were in the midline of the limb, namely rectus femoris and vastus intermedius; these patients presented with varying degrees of stiffness of the knee, or worse, with genu recurvatum. In Group II the main components involved were lateral to the midline of the limb, namely vastus lateralis and the ilio-tibial band; these patients presented with habitual dislocation of the patella, or worse, congenital lateral dislocation of the patella. In both groups untreated patients developed secondary adaptive changes such as subluxation of the tibia or marked genu valgum which made operative procedures more formidable and less effective. Release of the contracture should therefore be performed as early as possible.  (+info)

An operation for chronic prepatellar bursitis. (2/666)

An operation for chronic prepatellar bursitis is described in which only the posterior wall of the bursa is excised, thus preserving, undamaged, healthy and normally sensitive skin. This procedure is easier and less traumatic than complete excision of the bursa and results in fewer complications. It is suggested that removal of tha anterior wall of the bursa results in unnecessary and harmful interference with the underlying skin. The operation described gives a good functional and structural result; leaving the anterior wall of the bursa does not predispose to recurrence.  (+info)

The locked patella. An unusual complication of haemophilia. (3/666)

Mechanical derangements of the knee are an uncommon complication of chronic haemophiliac arthropathy. Two patients with locking of the patella were treated by manipulation. The mechanism of the injury was forced flexion of the knee joint beyond the limit of its restricted range. The injury is a serious one and may take six months to recover.  (+info)

Histomorphometry of the aging human patella: histologic criteria and controls. (4/666)

OBJECTIVE: A histomorphometric analysis of patellae from necropsies on persons between the third and tenth decades of life was carried out to trace the natural history of osteoarthritis. DESIGN: Minutiae of the histological changes in the surface and basilar portions of the articular cartilage were developed as criteria for the quantitation. A total of 99 patellas were harvested in the stated age range. The present study reports the results of ten grossly and radiologically normal specimens from subjects 23-32 years old served as controls. RESULTS: None of the control patellae were entirely histologically normal. Abnormality of the cartilage surface did not consistently proceed remodeling at the attachment to the subchondral plate. CONCLUSIONS: This observation throws into question the concept that osteoarthritis has a single histogenesis or always arises in articular cartilage.  (+info)

Knee pain and the infrapatellar branch of the saphenous nerve. (5/666)

Pain over the front of the knee is common after surgery or trauma but often a definite diagnosis is difficult to make. Over the past year we have seen five cases in which the pain could be ascribed to damage to a branch of the infrapatellar branch of the saphenous nerve. Two were subsequent to trauma and three to surgical procedures. In all five cases surgical exploration gave symptomatic relief. Eight cadaveric knees were prosected to explore further the anatomy of this nerve in relation to the injuries. Injury to one of these branches should be considered in cases of persistent anterior, anteromedial or anterolateral knee pain or neurological symptoms following surgery or trauma.  (+info)

Bone scintigraphy in chronic knee pain: comparison with magnetic resonance imaging. (6/666)

OBJECTIVE: To compare increased bone uptake of 99Tcm-MDP and magnetic resonance (MR) detected subchondral lesions, osteophytes, and cartilage defects in the knee in middle aged people with long-standing knee pain. METHODS: Fifty eight people (aged 41-58 years, mean 50) with chronic knee pain, with or without radiographic knee osteoarthritis, were examined with bone scintigraphy. The pattern and the grade of increased bone uptake was assessed. On the same day, a MR examination on a 1.0 T imager was performed. The presence and the grade of subchondral lesions, osteophytes, and cartilage defects were registered. RESULTS: The kappa values describing the correlation between increased bone uptake and MR detected subchondral lesions varied between 0.79 and 0.49, and between increased bone uptake and MR detected osteophytes or cartilage defects the values were < 0.54. The kappa values describing the correlation between the grade of bone uptake and the grade of the different MR findings was < 0.57. CONCLUSIONS: Good agreement was found between increased bone uptake and MR detected subchondral lesion. The agreement between increased bone uptake and osteophytes or cartilage defects was in general poor as well as the agreement between the grade of bone uptake and the grade of the MR findings.  (+info)

Knee cartilage topography, thickness, and contact areas from MRI: in-vitro calibration and in-vivo measurements. (7/666)

OBJECTIVE: This study assessed the three-dimensional accuracy of magnetic resonance imaging (MRI) for measuring articular surface topographies and cartilage thicknesses of human cadaveric knee joints, by comparison with the calibrated stereophotogrammetric (SPG) method. METHODS: Six fresh frozen cadaveric knees and the knees of four volunteers were imaged with a three-dimensional spoiled gradient-recalled acquisition with fat suppression using a linear extremity coil in a 1.5 T superconducting magnet. The imaging voxel size was 0.47 x 0.47 x 1.0 mm. Both a manual and a semi-automated segmentation method were employed to extract topographic measurements from MRI. Following MRI, each of the six cadaveric knees was dissected and its articular surfaces quantified using stereophotogrammetry. The MRI surface measurements were compared numerically with the SPG measurements. RESULTS: For six cadaveric knees, the average accuracies of cartilage and subchondral bone surface measurements were found to be 0.22 mm and 0.14 mm respectively and the thickness measurements demonstrated an average accuracy of 0.31 mm. It was found that while most of the error may be attributed to random measurement error, the accuracy was somewhat affected by systematic errors. For each bone of the knee, accuracies were most favorable in the patella, followed by the femur and then the tibia. The more efficient semi-automated method provided equally good and sometimes better accuracies than manual segmentation. CONCLUSIONS: This study demonstrates that clinical MRI can provide accurate measurements of cartilage topography, thickness, contact areas and surface curvatures of the knee.  (+info)

Localization of a gene for familial patella aplasia-hypoplasia (PTLAH) to chromosome 17q21-22. (8/666)

Patella aplasia-hypoplasia (PTLAH) is a rare genetic defect characterized by congenital absence or marked reduction of the patella. PTLAH can occur either as an isolated defect or in association with other malformations, and it characteristically occurs in the nail-patella syndrome and in some chromosome imbalances. We report the first evidence of linkage for isolated PTLAH in an extended Venezuelan family. After exclusion of the candidate chromosome regions where disorders associated with PTLAH have been mapped, a genomewide scan was performed that supported mapping of the disease locus within a region of 12 cM on chromosome 17q22. Two marker loci (D17S787 and D17S1604) typed from this region gave maximum LOD scores >3. Accordingly, multipoint analysis gave a maximum LOD score of 3.39, with a most likely location for the disease gene between D17S787 and D17S1604. Sequencing of the noggin gene, a candidate mapping between these markers, failed to reveal any mutation in affected subjects.  (+info)

  • The patella is covered at its proximal aspect by thick cartilage. (
  • The energy of the blow is absorbed by the fracture and may cause damage to the articular cartilage of both the patella and the femoral condyles. (
  • Patella femoralsyndrome is a medical term for any kind of damage to this cartilage, whether it is dueto injury, overuse, or some other reason, and it is particularly common amongathletes and people who are physically active. (
  • 2. Ali SA, Helmer R, Terk MR. Patella alta: lack of correlation between patellotrochlear cartilage congruence and commonly used patellar height ratios. (
  • Sleeve fractures are rare in the skeletally immature child and represent chondral or osteochondral injuries that occur between the cartilage sleeve and the main part of the patella and ossific nucleus. (
  • This is due to the anatomy of the immature patella, which begins to ossify at about 3-6 years of age and is surrounded by a layer of protective cartilage and soft tissue. (
  • During ossification, the patella is surrounded by a layer of protective cartilage that makes the bulk of the patella. (
  • Being one of the most commonly diagnosed orthopedic conditions in dogs, patella luxation accounts for 75% to 80% of orthopedic conditions seen in small animal clinics, and affects 7% of puppies, as early as 8 weeks of age. (
  • Lateral patella luxation refers to a dislocation away from body, while medial is a displacement closer to the body. (
  • Lateral patella luxation of toy and miniature breeds - This is found in toy and miniature breeds, such as Boston Terrier, Yorkshire Terrier, Chihuahuas, miniature and toy Poodles, Pomeranians, Pekinese, and Cavalier King Charles Spaniels. (
  • Following conditions may be associated with patella alta and There are a lot of conditions that are known to be associated with patella alta. (
  • In patella alta, a partially tilted patella protrudes above the level of the thigh, more remarkably so in unilateral cases. (
  • The thigh muscles are attached to the top of the patella. (
  • Radiographs of the knees showed a smooth, regular, semilunar radiolucent defect at the superolateral pole of each patella ( Figure 1 ). (
  • Another mechanism of injury to the patella is a tensile force, as is sustained with hyperflexion of the knee with an eccentric contraction of the quadriceps. (
  • Recurrent instability is uncommon unless there is a repeat contact injury to the patella. (
  • Eventually, if left untreated, the disease can progress to the point where the patella spends all of its time out of place. (
  • Simmons left Philadelphia's game against Washington on Wednesday midway through the third quarter because of injury, officially diagnosed as a subluxation of the left patella . (
  • Alternatively, patella instability may occur in patients that have a tendency for the condition because of how the ligaments and bones of the lower limb have developed around the knee. (
  • For best results, ice should be used immediately after your patella tendonitis injury or diagnosis. (
  • Neglect or delayed diagnosis is common and disastrous to the patient, who may go on to develop extensor lag and developmental disturbances of the patella (6). (
  • The aim of this paper is to highlight the importance of understanding the anatomy of an immature patella and of employing various teaching aids to make an early and accurate diagnosis. (
  • The patella was accessed using a mid-line incision and the diagnosis was confirmed intra-operatively (Figures 2a and b). (
  • the volume of the true patella plus that of the smaller ossification centers is greater than that expected of a normal patella. (
  • It‰۪s designed to boost the overall stability of the knee and improve patella tracking by applying mild pressure on the knee. (