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At least 163 records · Page 9Linked to original sources
PubMed1993

The structure of aggrecan fragments in human synovial fluid. Evidence that aggrecanase mediates cartilage degradation in inflammatory joint disease, joint injury, and osteoarthritis.

OBJECTIVE: To determine the proteolytic fragmentation patterns and N-terminal sequence of aggrecan fragments in human synovial fluid from patients with inflammatory arthritides, joint injury, or osteoarthritis (OA). METHODS: Knee synovial fluid was obtained from patients with joint injury, OA, acute pyrophosphate arthritis (pseudogout), reactive arthritis, psoriatic arthritis, or juvenile rheumatoid arthritis. Chondroitin sulfate-substituted aggrecan fragments present in the fluid were purified by cesium chloride gradient centrifugation and enzymatically deglycosylated. Core protein species were determined by N-terminal analysis and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with electroblotting and detection with monoclonal antibody 3B3. RESULTS: Samples from patients with joint injury, OA, and inflammatory joint disease all showed a similar 3-band pattern, with core sizes of approximately 200 kd, 170 kd, and 135 kd. In all samples, diffuse immunoreactive products were also seen, with an apparent size of > 250 kd. N-terminal analysis of core preparations of all samples showed a consistent single predominant sequence, beginning at alanine 374 of the human aggrecan core protein. CONCLUSION: The aggrecan fragments present in joint fluids from patients with various inflammatory arthritides, joint injury, or OA result from a predominant cleavage of the human aggrecan core protein at the glutamate 373-alanine 374 bond within the interglobular domain, between the G1 and G2 domains. The consistent pattern of fragments seen on SDS-PAGE and the single predominant N-terminal sequence suggest a common degradative mechanism of aggrecan in these different joint conditions. The identity of the proteolytic agent (aggrecanase), however, remains unknown. These results appear to have important implications with regard to the development of therapies to protect cartilage from degradation in patients with joint disease.

Adolescent↗
PubMed2006

Joint capsule matrix turnover in a rabbit model of chronic joint contractures: Correlation with human contractures.

To evaluate changes in matrix molecules of the joint capsule, the right knees of 24 skeletally mature female NZW rabbits were immobilized while the contralateral limb served as an unoperated control. The immobilization was discontinued at 8 weeks and the rabbits were divided among four groups (n = 6) based on the number of weeks the right knees were remobilized: 0, 8, 16, or 32. Three rabbits (six knees) that did not have operations provided normal control joint capsules. The mRNA levels for collagen types I, II, and III, and MMP-1 and -13 were significantly increased in the joint capsules of the contracture knees in all groups when compared to normal and contralateral limb joint capsules. In contrast, the mRNA levels for TIMP-1, -2, and -3 were decreased in the joint capsules of the contracture knees in all groups when compared to normal and contralateral limb joint capsules. The mRNA levels for lumican and decorin were increased in the joint capsules of the contracture knees in all groups when compared to normal capsules. Many of the changes observed in this animal model are similar to those observed in human joint capsules from posttraumatic elbow contractures, supporting the value of this rabbit model.

Animals↗
PubMed2006

Influences of tendon stiffness, joint stiffness, and electromyographic activity on jump performances using single joint.

The present study aimed to examine the influences of tendon stiffness, joint stiffness, and electromyographic activity on jump performances consisting of a single-joint movement. Twenty-four men performed three kinds of unilateral maximal jump using only the ankle joint (squat jump: SJ; countermovement jump: CMJ; drop jump: DJ) on the sledge apparatus. The relative differences in the jump height of CMJ and DJ compared to SJ were defined as pre-stretch augmentation. During jumping exercises, electromyographic activities (mEMG) were recorded from the plantar flexors. Ankle joint stiffness was calculated as the change in the joint torque divided by the change in ankle joint angle during the eccentric phase of DJ. Achilles tendon stiffness was measured using ultrasonography during isometric plantar flexion. No significant correlations were found between joint stiffness and pre-stretch augmentation in both CMJ and DJ. On the contrary, tendon stiffness was significantly correlated with pre-stretch augmentation in both CMJ (r = -0.471) and DJ (r = -0.502). The relative mEMG value of CMJ (to that of SJ) during the concentric phase was significantly correlated with pre-stretch augmentation (r = 0.481), although this relationship was not found in DJ. These results suggested that (1) the greater jump height in CMJ could be explained by both the tendon elasticity and the increased activation level of muscle, (2) tendon elasticity played a more significant role in the enhancement of jump height during DJ, and (3) joint stiffness was not related to either pre-stretch augmentation or tendon stiffness.

Achilles Tendon↗
PubMed1999

Isokinetic elbow joint torques estimation from surface EMG and joint kinematic data: using an artificial neural network model.

Because the relations between electromyographic signal (EMG) and anisometric joint torque remain unpredictable, the aim of this study was to determine the relations between the EMG activity and the isokinetic elbow joint torque via an artificial neural network (ANN) model. This 3-layer feed-forward network was constructed using an error back-propagation algorithm with an adaptive learning rate. The experimental validation was achieved by rectified, low-pass filtered EMG signals from the representative muscles, joint angle and joint angular velocity and measured torque. Learning with a limited set of examples allowed accurate prediction of isokinetic joint torque from novel EMG activities, joint position, joint angular velocity. Sensitivity analysis of the hidden node numbers during the learning and testing phases demonstrated that the choice of numbers of hidden node was not critical except at extreme values of those parameters. Model predictions were well correlated with the experimental data (the mean root-mean-square-difference and correlation coefficient gamma in learning were 0.0290 and 0.998, respectively, and in three different speed testings were 0.1413 and 0.900, respectively). These results suggested that an ANN model can represent the relations between EMG and joint torque/moment in human isokinetic movements. The effect of different adjacent electrode sites was also evaluated and showed the location of electrodes was very important to produce errors in the ANN model.

Adult↗
PubMed2003

Association between condylar position, joint morphology and craniofacial morphology in orthodontic patients without temporomandibular joint disorders.

The present study investigated condylar position and joint morphology in adolescent patients and elucidated the possible association between the joint structure and condylar position, and craniofacial morphology. Sixty-five adolescent patients were selected as subjects and their tomograms and lateral cephalograms were analysed. No significant differences in joint spaces were found between the right and left temporomandibular joints. Both the condyles in this population were located slight anteriorly in the glenoid fossa. With respect to the association between condylar position, joint morphology and craniofacial morphology, the ramus plane angle also exhibited significant negative correlations with posterior, lateral and medial joint spaces. Furthermore, there was a significant negative correlation between the gonial angle and the anterior joint space. These findings imply that the condyle was likely to show more posterior position in the glenoid fossa when the mandible exhibited clockwise rotation. In conclusion, the condyle in the adolescent subjects showed a symmetrical anterior position relative to the glenoid fossa. In addition, the joint spaces and it ratios were significantly related to the craniofacial morphology associated with vertical dimension. It is suggested that the condylar position may be affected by craniofacial growth pattern.

Adolescent↗
PubMedDate not supplied

Concrete use of the joint coordinate system for the quantification of articular rotations in the digital joints of the horse.

A method is detailed allowing the computation of three-dimensional (3D) joint angles. Each joint of the equine digit is modelled as a sequence of three single axis rotary joints. The Joint Coordinate System was used; it involves a specific sequence of cardanic angles. The decomposition of the angles was chosen so that the three elementary angles coincide with the flexion/extension, passive abduction/adduction and lateral/medial rotations. The algorithms and kinematic procedures were described for the equine front digital joints. This method was tested in vitro on four forelimbs. For each limb, angle values were measured while the member was loaded by a press (from 500 to 6000 N). These tests were repeated while a wedge raised one part of the hoof (toe, heel, lateral and medial sides) in order to induce modifications of the angular patterns of the joints. This method allowed a precise quantitative determination of 3D joint movements. The modifications occurring with the wedges are clearly identified and confirm some previously published semi-quantitative observations. Moreover, this method provides a way to collect objective data on the functional anatomy of joints and could be used to study connective shoeing thoroughly. It may be directly applied to other species and may be used by researchers interested in discreet articular movements, especially occurring in other planes than the sagittal one.

Anatomy, Veterinary↗
PubMed2003

Symptomatic hematoma of lumbar facet joint: joint apoplexy of the spine?

STUDY DESIGN: A case report. OBJECTIVES: To report and discuss a rare case of epidural hematoma that was considered to be formed as a result of idiopathic bleeding occurring at the facet joint (joint apoplexy). SUMMARY OF THE BACKGROUND DATA: Spontaneous spinal epidural hematoma is a relatively rare condition. According to a review article of 199 spontaneous spinal epidural hematomas in the last 2 decades, the majority of these conditions are thought to result from a rupture of the epidural vascular network. Recently, a hemorrhagic lumbar synovial cyst and a hematoma occurring from the ligamentum flavum were reported as rare types of epidural hematoma. METHODS: The authors describe the treatment and the clinical, radiologic, surgical, and pathologic findings in one patient with a rare epidural hematoma. RESULTS: Magnetic resonance imaging revealed that the extradural mass lesion was continuous with the right L4-5 facet joint; this was confirmed by surgery when the extradural hematoma was directly visualized. The joint cavity was also filled with the hematoma. There was no evidence of preceding cyst formation macroscopically or microscopically. The excised capsule of the left L4-5 facet joint revealed moderate hyperplasia of the synovium with an increased number of capillary vessels. CONCLUSIONS: This is the first reported case of radiculopathy considered to be a result of facet joint apoplexy in the absence of any preceding synovial cyst formation. The pathomechanism of the hemorrhage at the lumbar facet joint is unclear, but it is speculated that there could be an association with degenerative change of the facet joint. Surgical excision of this mass was considered to be the definitive treatment.

Female↗
PubMed2003

Lesser metatarsophalangeal joints: standard MR imaging, MR arthrography, and MR bursography--initial results in 48 cadaveric joints.

PURPOSE: To delineate the normal magnetic resonance (MR) imaging anatomy of the lesser metatarsophalangeal (MTP) joints in a cadaveric model and compare the MR arthrographic and MR bursographic findings with the standard MR imaging findings. MATERIALS AND METHODS: T1-weighted spin-echo MR imaging of 48 lesser MTP joints of 12 cadaveric feet was performed. The specimens were subsequently evaluated with MR arthrography, MR bursography, or both examinations. Musculoskeletal radiologists evaluated standard MR images to determine the normal appearances of the joint structures, especially the fibrous capsule, plantar plate, and collateral ligament complex (CLC). Signal intensity, morphology, joint thickness, relationships with adjacent structures, and best plane for analysis were analyzed. The contrast material-enhanced (ie, arthrographic and bursographic) MR imaging findings were compared with the standard MR imaging findings. RESULTS: The coronal plane was best for simultaneous depiction of the fibrous capsule, plantar plate, and collateral ligament complex and for assessment of the relationship between the CLC and the plantar plate. The sagittal plane was best for analysis of the bone attachments of the plantar plate and the transverse plane for evaluation of the CLC attachment sites in the phalanges. MR arthrography enabled identification of the bare areas and recesses of the joints, better delineation of the plantar plate articular surface, and better evaluation of the integrity of the soft-tissue components of the joints. Compared with the other examinations, MR bursography did not help improve these evaluations. CONCLUSION: MR imaging is an excellent examination for delineating the anatomy of the lesser MTP joints. Compared with standard MR imaging, only MR arthrography helps improve visualization of the fibrous capsule, plantar plate, and CLC of the lesser MTP joints.

Aged↗
PubMed1992

Muscle, joint, and tendon contributions to the torque profile of frog hip joint.

The relative contributions of muscle force, moment arm, and tendon compliance were determined as a function of joint angle in the frog semitendinosus-hip joint system. Muscle, joint, and tendon properties were individually measured and then combined to predict the torque generated at the hip joint as a function of joint angle (i.e., the hip torque profile). Predicted torques were then compared to experimentally measured torques using a stepwise regression model to quantify the relative importance of muscle, joint, and tendon contributions to the hip torque profile. Variation in moment arm accounted for 74% of the variability observed in the hip torque profile, while addition of the muscle's intrinsic sarcomere length-tension property accounted for an additional 19% of the torque profile variability. Tendon compliance, which permitted a small amount of sarcomere shortening, accounted for only about 4% of the torque profile variability. We conclude that in this muscle-joint system, the relative fiber length-to-moment arm ratio is the major determinant of the shape of the isometric joint profile. The fiber length-to-moment arm ratio in other mammalian systems is also discussed.

Animals↗
PubMed2004

Proximal tibiofibular joint ganglion cysts: excision, recurrence, and joint arthrodesis.

OBJECTIVE: Proximal tibiofibular joint proximal tibiofibular joint cysts are rare entities that can cause disability. Excision remains the traditional surgical treatment. Cyst recurrence has been a problem. This study reviews one of the largest series of patients with proximal tibiofibular joint cysts and evaluates the role of a new surgical option, proximal tibiofibular joint fusion. METHODS: Thirteen patients were admitted to the institution between 1987 and 1999. Diagnoses were confirmed by magnetic resonance imaging and histological examination. A database was compiled after medical record review. Patients completed a phone survey describing activity levels, symptom severity, recurrence history, and additional surgery. Average postoperative follow-up and average time to date of survey were 1.7 and 6.3 years, respectively. RESULTS: Patient complaints included lateral knee "fullness" (75%) and peroneal nerve dysesthesias (54%). Twelve patients opted for surgery: cyst excision (8) and cyst excision with proximal tibiofibular joint fusion (4). A recurrence rate of 13% (1 of 8) following primary excision was observed. A 100% (3 of 3) repeat recurrence rate was noted in second resections. Four patients underwent proximal tibiofibular joint fusion: 2 with a recurrence history and 2 for primary treatment. At follow-up, all fusion patients were without cyst recurrence or activity limitations. Procedure morbidity was minimal. CONCLUSIONS: Proximal tibiofibular joint cysts can recur after simple excision. Repeat resection after a recurrence is often not effective. Proximal tibiofibular joint arthrodesis appears to be a more effective surgical option after a recurrence.

Adult↗
PubMed1990

Comparative histological contributions to the development of the ear-ossicular joints and the temporomandibular joint in the mouse.

The genesis, differentiation, development and growth of the ear-ossicular joints and temporomandibular joint (TMJ) in the Slc-ICR mouse were studied by means of light and transmission electron microscopy. The differentiation of the ossicular joints and TMJ anlagen was initiated during the fetal stages. Although morphogenesis, development and growth of the TMJ were already evident in the prenatal stages, the joint-cleaving associated with the occurrence of interzones in the cartilaginous ossicular chain was observed during the neonatal stages. However, the simple diarthrodial ossicular joints were completed and became mature earlier than the double synovial TMJ having an articular disc in early postnatal life. TEM examinations revealed that the articulating epiphyseal cartilage of the ossicular joints consisted of hyaline cartilage, while the intracapsular structures in the TMJ were composed of fibrocartilage. The synovium of the diarthroidal joints was supplied by blood vessels, nerve fibers, collagen and elastic fibers. No distinct aging in the cellular and fibrous components of the synovial tissue of the completed TMJ and ossicular joints was evident in the present study.

Animals↗
PubMed1995

The effect of intercarpal joint motion on wrist motion: are there key joints? An in vitro study.

The contribution of each intercarpal joint individually and as a member of a regional group to total wrist motion was analyzed in 10 fresh, frozen cadaver specimens. Each intercarpal joint had an effect on the total wrist motion, but the contribution of each to the different planes of motion was not equal. The scaphoid-capitate joint had a governing effect on the motion of a region comprised of scaphoid-trapezium, scaphoid-trapezoid, and scaphoid-capitate. The lunate-capitate joint had a governing effect on the motion of a region comprised of the lunate-triquetrum, lunate-capitate, triquetrum-hamate, and hamate-capitate complex. Elimination of motion in either of the key governing joints affected total wrist motion the same as elimination of motion in all the joints in that region. Intercarpal fusion for treatment of ligament injury of the proximal intercarpal row may be limited to the scaphoid-capitate or lunate-capitate joint. There is no need to attempt fusion in all joints of either of the two regions.

Adolescent↗
PubMedDate not supplied

Estimation of joint fluid volume in the knee joint of rabbits by measuring the endogenous calcium concentration.

OBJECTIVES: The purpose of this study was to develop a new, simple, and more efficient method for estimating joint fluid volume in the knee of experimental animals by measuring endogenous calcium concentration, which is maintained rigidly at a constant level in the body fluid. METHODS: Calcium concentrations in the plasma and joint cavity lavage were colorimetrically measured in normal and papain-induced arthritic rabbits. The joint fluid volume was estimated by dividing the total calcium concentration in the joint cavity lavage (microg/joint) by calcium concentration in the plasma (microg/ml). To confirm the relevancy of this method, radioactivity in the plasma and joint cavity lavage was determined after intravenously injecting 3H2O. The correlation between the joint fluid volumes obtained from the two different methods was examined to evaluate the validity of the method involving measurement of the calcium concentration. Results The joint fluid volumes of normal rabbits were estimated at 401 micro/joint and that in the arthritic rabbits at 680 microl/joint by measuring calcium concentration, respectively. These values were not significantly different from those estimated by radioactivity in the plasma and joint cavity lavage (normal: 425 microl/joint, arthritis: 761 microl/joint). A statistically significant correlation was observed between the values obtained from the two methods (r = 0.985). This method is considered useful for the evaluation of therapeutic medicine for arthritis or for hydrarthrosis research using experimental animal models.

Animals↗
PubMed1986

[Principles of joint protection in inflammatory joint disease with special reference to biomechanical status].

With respect to rehabilitation in inflammatory joint diseases, the activity of the disease, the influence of the disease on the physical ability and social and psychological situation of the patient should all be taken into consideration and treatment then planned accordingly. In the present article, special attention is paid to the biomechanical situation in the diseased joints of the upper and lower extremities, respectively. In the shoulder and elbow joints, the muscles working with long levers and the loading of joints create large intra-articular forces. In the hands the vulnerable joints are under high intra-articular stress because of loading in all situations in daily life. As the result of synovitis and destruction of cartilage, instability is often present. In the lower extremities, the hips and knees are under great strain when moving, rising from chairs, and walking on stairs. Much can be done to reduce loading on the joints. In the upper extremities splinting and the use of suitable technical aids are essential. In the lower extremities good quadriceps muscles and hip extensor muscles as well as correct loading techniques are essential. Whenever walking aids are used, they should be tried out with attention to grip function and the condition of the shoulder and elbow joints, as well as to the need of unloading the lower extremities. A walking aid should always be checked again later. A daily contracture prophylaxis program should help to prevent deformities. Strength training should be performed with attention to the intra-articular loading and stability of the joints.

Arthritis, Rheumatoid↗
PubMed1983

[Acoustical analysis of joint-sound through passive motion--with special reference to degenerative osteoarthrosis of the knee joints].

Sounds from the joints are still in the mysterious zone. It seems to be important to study the sound which occurs on motions. Here, a new analysing method and its clinical application are presented and discussed. The joint which is studied, is moved in some ranges for four seconds in the unechoic chamber, and a special microphone is kept to touch on the pan-articular skin manually throughout the motion. These collected sounds are analyzed with a narrow band spectrum analyzer (Br uel & Kjaer Co., 2031 Type) and a computer. In the unechoic chamber, it may diminished the background noises. The narrow band spectrum analyzer made it possible not to use the magnetic tape which usually induced much noise. Furthermore, as the computer system is utilized, it become easy to compile the data of each frequency analysis and to obtain over all value, with which the sound volume can be compared with each other. The over all value means an integrated volume of each joint sound. In this paper, joint sound were obtained from normal and pathological human joints. In the normal cases, the frequency analysis data showed almost flat spectrum curves, and the total over all values (0.5 kHz to 5 kHz) were usually less than 80 dB. On the other hand, in the pathological joints which had bony changes affected by rheumatoid arthritis, degenerative osteoarthritis, fracture, and others, the frequency analysis showed elevated curves in range from 0.5 kHz to 4.0 kHz, and the total over all value increased in each pathological joint. In 85 cases of osteoarthrosis of the knee joints, the total over all values were a wide dispersion from 76 to 104 dB. And these values and radiological grading (by Swanson) correlated to each other. The over all values at each 0.5 kHz interval, especially from 0.5 to 1.5 kHz, were maximum ones in each radiological gradings. It is concluded that these results in osteoarthrosis cases, are related to with radiological gradings.

Acoustics↗
PubMed1980

The joints of the evolving foot. Part II. The intrinsic joints.

A description is given of the functional morphology of the intrinsic joints of the foot, with particular reference to the primates, and an attempt is made to define the key human derived features. In the human subtalar joint the compromise axis has become reoriented into a very elevated position and more nearly in line with the functional foot axis than it is in subhuman primates. This provides for torque of the talus, and so the supported body weight, about the axis, during the stance phase of gait. In the subhuman primates the very oblique subtalar axis is important in inverting the foot into a grasping attitude. In subhuman primates the transverse tarsal joint complex plays an important role in supination of the forefoot, which complements inversion at the subtalar joint complex in achieving the ideal grasping position. This movement is only rendered possible by a helical action at the subtalar joint complex. In man the calcaneocuboid joint has been remodelled so as to bring the lamina pedis into a close-packed position during the latter part of the stance phase of gait. The joints between the cuneiforms and the cuboids, and the associated tarsometatarsal joints show significant modifications in man.

Animals↗
PubMed1993

[Areas of contact in human humero-ulnar joints as a function of pressure, their connection through subchondral mineralization and joint surface morphology of the incisura trochlearis].

Evaluation of the stress distribution in joints can be obtained directly from contact areas and pressure forces, and also indirectly from the functional adaptation of the connective tissues. Therefore 8 human humero-ulnar joints, fixed in formalin, were examined for size and position of contact areas (polyether casting/Vidas image analyser) and their dependence upon the joint forces (Zwick material testing machine). The distribution of subchondral mineralisation was assessed, using CT osteoabsorptiometry. Depending on the joint force, the contact areas increase from about 10% of the total surface (20 N) to approximately 60% (1280 N). With weak forces they are localised ventrally and dorsally in the joint, with more powerful forces they run together centrally. With a divided articular surface they join at about 160-640 N, with a continuous surface, at about 40-80 N. Divided joint surfaces show a bicentric mineralisation pattern of the subchondral bone with ventral and dorsal maxima. Continuous surfaces, on the other hand, usually show central maxima. Both the mineralisation pattern and the position of the contact areas suggest a physiological incongruity of the humero-ulnar joint surfaces, which vanishes with increasing pressure due to viscoelastic deformation of articular cartilage and subchondral bone. More marked incongruity is postulated for the divided surfaces than for the others. The consequent peripheral transmission of pressure seems to involve a functional principle, which, present in several human joints, leads to both optimal distribution of the stress and better nutrition of the articular cartilage.

Aged↗
PubMed2001

Does joint effusion on T2 magnetic resonance images reflect synovitis? Comparison of arthroscopic findings in internal derangements of the temporomandibular joint.

OBJECTIVE: The purpose of this study was to clarify the characteristics of joint effusion (JE) in the temporomandibular joint by comparing T2-weighted magnetic resonance (MR) images with arthroscopic findings. STUDY DESIGN: MR images of 47 symptomatic temporomandibular joints (47 patients) with internal derangement associated with painful hypomobility were taken to evaluate the degree of JE on a scale of 0 to 3. Within 2 months after MR images, arthroscopic findings with respect to the severity of synovitis, adhesion, and degenerative change in the superior compartment were each quantitatively assessed on a scale of 0 to 10. The arthroscopic scores were compared among the 4 JE grades, as well as between 2 groups, effusion-present (grades 2 and 3) and effusion-absent (grades 0 and 1), by using the Spearman correlation coefficient and the Mann-Whitney U test. RESULTS: The distribution of JE was as follows: 10 joints had grade 0, 5 joints had grade 1, 19 joints had grade 2, and 13 joints had grade 3. The synovitis score had a significant relationship to the degree of effusion (P =.0012) and was higher in the effusion-present group (6.4 +/- 2.0) than in the effusion-absent group (4.2 +/- 1.6) (P =.0005) On the other hand, there was no statistically significant correlation between either adhesion or degenerative change and effusion. CONCLUSIONS: JE may reflect synovitis; however, the nature of JE itself needs to be further elucidated by additional studies.

Adolescent↗