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At least 163 records · Page 9Linked to original sources

Human zygapophyseal joint capsule and synovial fold innervation.

The anatomy of human lower lumbar zygapophyseal joint postero-medial fibrous capsules, and their synovial folds, was investigated by high-power light microscopy and transmission electron microscopy. A description of nerves in the postero-medial joint capsule and the synovial folds is presented. The diameter of paravascular myelinated nerve fibres in the synovial folds was 0.2 micron (micron). Small myelinated nerves (0.6 to 12 microns) course through the synovial folds, not in association with blood-vessels, suggesting that these nerves are nociceptive and, therefore, may have clinical significance in spinal pain.

Adult↗

Tensile properties of the knee-joint capsule at an elevated intraarticular pressure.

In order to evaluate the capsular reaction to high intraarticular pressure (IAP) in the knee during arthroscopy, we examined 13 patients admitted for elective surgery with joint infusion to 30, 70, 120 and 170 mmHg IAP (4, 9.3, 16 and 22.7 kPa). The infusion was repeated once, at all IAP levels except 30 mmHg, after 2 min and was recorded for another 2 min. A pressure-time curve was recorded as a combined effect of viscoelastic properties of the capsule and extraarticular fluid absorption. 3 more knee joints were infused directly to 170 mmHg and a pressure-time curve was recorded for 15 min, after which time the joint was reinfused to 170 mmHg in order to estimate the change in joint volume due to absorption or relaxation. In 10 knees, the curves were uniform. At infusion, the pressure curve was almost linear above 70 mmHg. There were no signs of plastic deformation of the joint capsule at pressures below 120 mmHg, while at 170 mmHg there were signs of capsular deformation. At each pressure level, the curve revealed a rapid fall in initial pressure that gradually decreased because of capsular relaxation or fluid absorption. Repeated infusion delayed the fall in pressure, due to increased capsular stiffness. In 3 knees infused directly to 170 mmHg IAP, the slope for the first 2 min of the pressure-time curve did not differ from that found at maximal IAP in knees examined with stepwise increasing pressures. Discontinuity of the capsule, even of puncture size, influenced the pressure/volume correlation considerably. We conclude that at IAP levels of 170 mmHg, there are signs of plastic deformation of the joint capsule. In order to avoid capsular damage, knee arthroscopy should be done at intraarticular pressure levels below 120 mmHg.

Absorption↗

Shoulder joint capsule distension (hydroplasty): a case series of patients with "frozen shoulders" treated in a primary care office.

"Frozen shoulder," most often caused by adhesive capsulitis, is frequently treated with intra-articular steroid injections, physical therapy, and surgical manipulation under anesthesia. These therapies provide limited benefits. Hydraulic distension of the shoulder joint capsule (hydroplasty) has potential to provide rapid relief of pain and immediate improvement of shoulder function for patients with adhesive capsulitis. We performed 21 hydroplasty procedures on 16 patients over a 4-year period. Ninety-four percent (17/18) of the procedures improved patient's measured mobility immediately after the procedure. Fifty-three percent (10/19) of the procedures produced immediate, short term, and sustained improvement in comfort and function. No significant complications of the procedure were detected. Our series suggests that the hydroplasty procedure should be further evalutated.

Adult↗

Degeneration and regeneration of Ruffini corpuscles in the joint capsule.

The Ruffini corpuscle is a highly-differentiated sensory corpuscles which consists of complexly-arborized axon terminals surrounded by Schwann cells. The present study examined by electron microscopy the morphological changes of Ruffini corpuscles in rat joint capsule during their degeneration and regeneration, following nerve crush. Initial sign of axonal degeneration was seen as early as one day after nerve crush, and by day 3, axon terminals disappeared from Ruffini corpuscles, Schwann cells became shrunken and atrophic by day 5. Regenerating small-diameter axons first appeared about 10 days later in the denervated corpuscles, and they gradually thickened, developing into matured terminals. At the same time, atrophic Schwann cells recovered their original vigorous state about 30 days after nerve crush. No findings were obtained that suggested the neogenesis of the corpuscle by regenerating nerves. These findings show that regenerating axons enter the original denervated corpuscle and, by associating with remaining atrophic Schwann cells, develop into axon terminals as in the normal corpuscle.

Animals↗

Glycosaminoglycan metabolism of the medial meniscus, the medial collateral ligament and the hip joint capsule in experimental osteoarthritis caused by immobilization of the rabbit knee.

A study was made of glycosaminoglycan metabolism in experimental osteoarthritis caused by immobilization of the rabbit knee in extension. Samples from the medial meniscus, the medial collateral ligament of the knee and the hip joint capsule were obtained and analysed after 2, 6, 10, 17, 30 and 87 days of immobilization, samples from the mobile limb serving as controls. The tissue concentrations of glycosaminoglycans were determined from measurements of hexosamine and uronic acid after prior papain proteolysis and subsequent purification. The uptake of 35S-sulphate (DPM/microgram hexosamine) was used as an indicator of the synthesis rate of sulphated glycosaminoglycans. In both early and advanced immobilization osteoarthritis, the synthesis rate and the content of glycosaminoglycans were increased in all tissues.

Animals↗

Arthroscopic relationship of the axillary nerve to the shoulder joint capsule: an anatomic study.

Twelve right shoulders in fresh cadavers were dissected to determine the relation of the axillary nerve to the shoulder capsule and glenoid. Needles transfixed the nerve to the capsule and into the shoulder joint. Arthroscopy was performed to determine the location of the needles on the glenoid clock. The needles were then removed and the position of the shoulder changed to determine the effect on the position of the axillary nerve. The axillary nerve was held to the shoulder capsule with loose areolar tissue in the zone between 5 and 7 o'clock and was close to the glenoid in the neutral position, in extension, and in internal rotation. With shoulder abduction, external rotation, and perpendicular traction, the capsule became taut and the axillary nerve moved away from the glenoid. Abduction, external rotation, and perpendicular traction increase the zone of safety during arthroscopic anteroinferior capsulotomy adjacent to the glenoid between the 5 and 7 o'clock positions.

Aged↗

A composite micromechanical model for connective tissues: Part II--Application to rat tail tendon and joint capsule.

A micromechanical model of fibrous soft tissue has been developed which predicts upper and lower bounds on mechanical properties based on the structure and properties of tissue components by Ault and Hoffman [3, 4]. In this paper, two types of biological tissue are modeled and the results compared to experimental test data. The highly organized structure of rat tail tendon is modeled using the upper bound aggregation rule which predicts uniform strain behavior in the composite material. This model fits the experimental data and results in a correlation coefficient of 0.98. Applied to cat knee joint capsule, the lower bound aggregation rule of the model correlates with the data and predicts uniform stress within this more loosely organized tissue structure. These studies show that the nature of the interactions between the components in tissue differs depending upon its structure and that the biomechanical model is capable of analyzing such differences in structure.

Animals↗

[Studies on the surface and new joint capsule of McKee-Farrar prosthesis implanted for several years (author's transl)].

These studies are intended as a critical contribution to the question, wether the McKee-Farrar (MF) prosthesis, on account of its stronger friction and the consequences of this, as compared to other models, still has its justification or wether these "secundary" manifestations indicate that this prosthesis should be abandoned. Studies on primary and secundary alteration of the surface were carried out on exchanged MF prosthesis with the aid of the grid electron microscope. The signs of wear are clearly visible and can be differenciated from production artefacts. The movement and deposit of abraded particles into the new joint capsule was studied qualitatively and quantitatively with the aid of radioisotopes. All samples showed an increased accumulation of chrome in the tissues as compared to cobalt. There is no indication of significant damage. On the basis of the results of these studies and on account of the favourable personal experience from a surgical and clinical point of view -- particulary with reference to minimal preparation of the acetabulum and ready replacement, the MF prosthesis will continue to hold its place as the standard model for total prosthetic hip joint replacement.

Aged↗

Histologic evaluation of the glenohumeral joint capsule after radiofrequency capsular shrinkage for atraumatic instability.

We evaluated histologically 10 biopsy specimens taken preoperatively from the anterior-inferior glenohumeral ligament from patients with atraumatic instability who had undergone radiofrequency capsular shrinkage, 10 taken immediately postoperatively, and 13 taken before revision. The synovial and subsynovial layers returned to normal histology in biopsy specimens taken from 6 months onwards. Collagen bundles in the fibrous layer continued to have a reparative histology during the period of the study (up to 37 months). The type of radiofrequency probe used (monopolar or bipolar) had no effect on the histologic healing process (P > 0.5, chi2 test). A histologic score was introduced, and this was found to have an excellent intraobserver agreement (weighted kappa, 0.840) and a moderate interobserver agreement (weighted kappa, 0.698).

Adolescent↗

Dependence of EMG-reaction times of the rectus femoris on position changes of the hip joint--role of the joint capsule.

EMG-reaction times (EMG-RTs) of the rectus femoris in midposition (M) and internally rotated position (IR) of the right hip joint were examined in nine control subjects and nine patients who had lost most of the capsule of a hip joint after total hip joint replacement procedure. In both groups EMG-RTs of the rectus femoris were faster at IR than at M. The difference of EMG-RTs between M and IR was essentially the same in the two groups. It is assumed that information from proprioceptors in the joint capsule may not play an important role in postural dependence of EMG-RTs of the muscle.

Adult↗

Ruffini mechanoreceptors in isolated joint capsule: responses correlated with strain energy density.

Mechanoreceptive afferents innervating the posterior capsule of the cat knee joint were recorded in a preparation of isolated capsule. The purpose of the experiments was to identify mechanical states in the capsule that were associated with afferent discharge. The capsule was excised from the knee with its bone attachments intact, so that the geometry of the capsule could be reproduced in vitro. The capsule was deformed, and measurements were made of stresses and strains in the plane of the capsule. Afferent discharge was correlated with each of the components of plane stress, plane strain, and strain energy density (SED). SED, the stored elastic energy at the receptor location, was the only mechanical variable that was consistently positively correlated with afferent discharge. A model of the Ruffini-type receptor is presented that accounts for the sensitivity to SED.

Afferent Pathways↗